# Building Jerry's Donkey



## Captain Jerry (Apr 26, 2010)

I think I am committed or should be. This may be more than I can handle, but I am going to go for it. I have photographed, measured, modeled, cogitated and procrastinated as l long as I can. I think I have identified the more difficult parts and I feel confident that with a little bit of help, I can get through this. 

I have not purchased any plans or books that detail building this kind of model, with the exception of a copy of the original manufacturers brochure, not from any purity of purpose, but just because I get the greatest satisfaction from solving problems rather than repeating someone elses solution. That does not mean that suggestions and observations are not welcome. They absolutely are! I just wanted to start with a blank slate. Well not really, I've done a lot of drawings and plans but there will be obstacles ahead that I can't see from here. so please comment If you see me headed down the wrong path.

Today I built the first part. I want to build this thing from the bottom up so I started with the base. From what little I have seen of other donkey models, the seem to use formed channel to fabricate the base. I don't know if that is right or wrong, but the example I have to go by seems to use castings for the base elements. The components of the base are either welded or bolted together. The first clue is that the side and back rails include lugs that extend beyond the edge of the lower flange that were used to bolt the unit to the deck or skid. These lugs do not appear to be welded. Also, on the top of the front cross beam, the manufacturer's name "American Hoist & Derrick Co., St. Paul, Minn." appear in well formed raised letters. That's a casting.

I'm not going to start casting. This will be all bar stock or plate but it does make a difference. If the base were channel, you would just drill or burn a hole for mounting bolts. Most available aluminum channel or angle extrusions are to thin to suit this. A trip to the junk yard yielded a 12" length of heavy 6" extruded channel. The back and flanges are 3/16" thick and the flanges are 1.5" wide.

A slitting saw would make this into the material I needed. Slitting saws are expensive so I used an inexpensive alternate. Harbor Freight sells a little (very little) cut-off saw for about $30 that uses a 1.5" dia HSS blade that is very thin. The blades sell 3 for $9.95.  Sorry, forgot to measure and the shop's closed, so very thin. Very fine teeth and hollow ground. With a little care, it produces surprising results, Here is a picture of it ripping slices from the channel, making angles.






The thin blade is flexible, so if it is crowded, it will tend to warp and run of line and bind. I make the first pass just to the depth of the teeth, feeding into the cut. I increase the depth of cut on the return pass. (climb cutting), but the grove left from the first pass is full of WD40 so the cut is smooth as fast as I can crank.  The next forward pass is to full depth and feed is only a little slower with an occasional spray of WD40. The finish cut is as smooth as you could want.

Once the pieces are a little more manageable, ordinary milling techniques yield the finished parts. I show them here screwed down to a piece of high density polyethelene (HDPE) using the above mentioned lugs. Here is the base:






Here is another shot with the boiler (paint can) and hoist gears (not yet), just for scale. 






By the way, I have decided to use 1/10th scale. The finished model will be just over 9" long and 5" wide including the front hoist drum that mounts on a bolt on frame extension. At this point, I plan to build the model to run on air, with a simulated boiler for appearance. Whether or not I build a working boiler at a later date is undecided.

Start the clock, it's under way. Next will be to add the deck plate. 

Jerry


----------



## 4156df (Apr 27, 2010)

Jerry,
Congratulations on deciding to go for it. This will be a fun build to follow. Great start, too!
Dennis


----------



## Jared (Apr 27, 2010)

All right! Looks like you've got a good start. I'll be keeping an eye on this.


----------



## Maryak (Apr 27, 2010)

Jerry,

Onya mate, watching with great interest. :bow: :bow:

Best Regards
Bob


----------



## b.lindsey (Apr 27, 2010)

Great start Jerry...This will be a fun one to watch!

Bill


----------



## SAM in LA (Apr 27, 2010)

Jerry,

I'll be following your build closely.

I have a feeling that I will learn a lot from this.

SAM


----------



## Captain Jerry (May 5, 2010)

Deck plate. Should be simple. Just a rectangular piece of 1/8" aluminum plate with a round hole and a rectangular hole. Simple until I got started. How do you hold a 6" x 8" plate in a 2.5" vise. I decided to bolt the plate to a 2.5" x 2.5" x 3/8" aluminum plate, grip the square piece in the vise and mill th plate to dimension. Second complication. How do you mill a finished 4.8" x 6.75" plate on a mill that only has a 4" Y travel. Lots of head scratching and no quick easy solution. I wound up having to move and re-square the vise three times. That let me get the plate to finished dimension. The plate was then bolted down to a sacrificial plate of HDPE and then milling out the rectangular hole with a 3/16" end mill. The round hole was cut with the end mill by pivoting the plate and the sacrificial plate around a bolt held in the vise with a v-block. 

Sorry about the lack of pictures. This was a messy and unattractive procedure and probably not a good example for anyone to follow. I did take some pics but forgot to take my shop chip out of the camera and the pics got deleted by my wife at my great-granddaughter's birthday party. Just as well.

Here is the present state of the project. Base with deck plate, two front hoist frames, and one main hoist frame. The frames are just roughed out for fitting. They will have additional detailing added when I receive the ball-end mill and rotary table that I have on order. 
















I have come to the conclusion that this project cannot be completed without a rotary table/indexer. This project is really about the hoist mechanism and the hoist mechanism is geared. Yes, I could buy gears and I would if the gears were incidental to the project but in this case, they are central to the project, so If I can't make the gears, I should pick another project.

So in the coming weeks, I will either make a set of gears or make a sharp right turn and look for another project. Watch me if you want to. I promise to take pictures.

Jerry


----------



## TarheelTom (May 5, 2010)

Just curious. Does anyone know where the term "donkey engine" came from?

Tom


----------



## b.lindsey (May 6, 2010)

Jerry,
The base if looking great so far, and even with the limitations in travel/vise capacity, etc. it looks like a nice job. I wish you success in the gear cutting and will be watching for that as I hope to cut two gears for my current project. I suspect that once you get that rotary table you will wonder how you did without it :big:

Keep up the good work!

Bill


----------



## 4156df (May 6, 2010)

Jerry,
This is a great start to a tough project. I like your attitude on making the gears. Lot's of pictures please. Gears are a demon I've got to face one of these days, too.
Dennis


----------



## Captain Jerry (May 9, 2010)

I don't have the rotary table/indexer yet but I am going to start on the gears. Here are the gear specs.

The hoist gears (2) will be 24 Pitch, 60 tooth, 14.5 PA , 2.5" pitch diameter, 2.6" blank diameter, 1.19" tooth 
root diameter, .496" tooth face radius, 36.3 degree tooth face angle, .5" tooth face.

The pinion will be 24 Pitch, 12 tooth, 14.5 PA, .5" pitch diameter, .582" blank diameter, .396" tooth root 
diameter, .0992" tooth face radius, 54.7 degree tooth face angle, .5" tooth face.

I hope I don't have to make many gears so purchased cutters are out. I'll go with a tool bit in a flycutter for the
tooth profile. Grinding the cutter would be a lot easier if I new what it was supposed to look like so thats where 
I'll start. There are several gear vendor web sites with a bunch of free information. This is the one I used:

http://www.rushgears.com/Tech_Tools/PartSearch5/partSearch.php?gearType=SPUR

It has a table that lets you design a custom gear and then download a detailed CAD file. The download comes in a
variety of flavors so I used the .STEP format and imported it into ALIBRE as a new part and then created a drawing. All of the critical dimensions can be read on the drawing.

As a rookie, it seems to me that the most difficult part of grinding the tool would be getting the radius of the 
tooth face and the apparent angle of the tooth faces. I don't really see this angle specified in any gear tables. 
It is not the same as the pressure angle which is the same on both gear and pinion. The angle that I am referring 
to is greater on the pinion than it is on the driven gear. It can be constructed by drawing a line through the 
ends of the arc on opposing tooth faces and taking the included angle. It is easier to do than to say so take a 
look at the drawing.






I will use this to form the first operation on the tool blank. Just grind a pointed tool to this angle on the bench grinder, with appropriate relief angles. I'm using 3/16" HSS tool blanks.

Once you get the tool to the pointy shape. then grind the face concave to the right diameter. On the big gear, the angle is 36.3 degrees, and the tooth face radius is .496". To get the radius on the tool, just dress a mounted 
point to a diameter of .983" or just slightly less than 1". Then just a few touches of the stone to the flat face 
of the tool from the previous operation and your almost there. Adjust the length and put a small radius on the 
corners of the tip and its done. After a little experimentation, i find this fairly easy on the bench drill press with the tool held in my little tool makers vise and with the table set to a 15 degree angle. With the small diameter stone and at about 2500 RPM, it is easy to control the process and heat is not a big problem. There is not much material to remove it doesnt take much more than a touch on either face. With the table sloping up and away from you, and alternating from side to side, it is not hard to keep the shape symetrical. The goal is a smooth arc to the full diameter of the stone on either side. You can blue the top of the tool and scratch a center line to help if you think you need it.










The large stone is for the big gear and the small stone is for the pinion.














Checking the profile against the drawing verifies the shape. When the tooth face profile looks good, holding the tool so i points uphill into the stone, put a little radius on the corners and grind a bit of relief on the tip.

Now to make the flycutter. I used a 3/4" bolt, taking the corners off of the head and reducing the shank to 1/2" in the lathe. Then over to the mill to cut a slot across the face of what was the bolt head with a 3/16" end mill. The slot is not centered in head but is offset so that the cutting edge of the tool is on the centerline which results in a neutral top rake. OK to cut aluminum or brass but the top of the tool may have to be relieved for steel.














I didn't cut the slot full width so that the cutting tool bottoms out in the slot. I milled a flat parallel to the cutting tool slot and drilled and tapped a couple of holes for set screws. I probably didn't do this right and if I have to do it again, I'll put the set screws on the other side so the force the tool agains the bottom of the slot instead of the top. It may not make much difference.

I think I'm ready. Waiting for the Fed Ex truck............

Jerry


----------



## Deanofid (May 9, 2010)

This project is coming along nice, Jerry, and it looks like you're well on your way with the gear cutting.
I do it a similar way when I don't have an example gear to use to pattern the single point cutter.






Just a little encouragement there, thinking you are on the right track. That cutter is pretty small, being
for a gear in of much higher pitch, but it was done the same as yours. Oh yes, it works!

Keep it up, and thanks for the pics and great write up.

Dean


----------



## Maryak (May 9, 2010)

CJ,

One way to achieve this radius on the tool is to print your drawing onto an overhead transparency. Using an overhead projector, (now where will I find one of those, local school, college etc probably thrown in the back room with the advent of powerpoint). Enlarge this onto a wall and then offer your tool over the transparency and compare. Surprising how close you can get. I learned this trick from an artisan who used to paint scenery using an OHP, an enlargement onto the canvas and trace by numbers.

Hope this helps. 

Best Regards
Bob


----------



## Captain Jerry (May 10, 2010)

Dean,

Thanks for the encouragement. I have tried the cutter on scrap aluminum (one tooth) and it works great. Nice finish and clean sharp edges. I got good results on steel as well after gashing the slot with a slitting saw and grinding positive rake on the top of the tool. I don't have anyway to index a gear blank yet so I was just checking the tool's cutting ability to be sure that I had the right geometry. The tool cuts just fine but I'll wait for the indexer to test the tool profile.

Bob,

Good idea with the OHP. Schools would be a good place to find one but I think they lock the doors pretty securely and probably have alarm systems. I'll let you know.

Jerry


----------



## Captain Jerry (May 25, 2010)

Everything that we have done before gets us to where we are, or as William Shakespeare says it "what's past is prologue." If that is so then the gear on the left took almost 72 years to make and the gear on the right took another hour! This project only needs one drive pinion and the first one was good enough to use, but it was so surprisingly easy that I had to do it again. Maybe I'll put the first one on my key chain and show it off to my kids, grand kids, and great grand kids. They are polite enough to fake an interest.






This is what I did today and I am in a state of shock! I made gears!!! It isn't impossible!!! I didn't take any pictures for several reasons. First of all, the level of fear, intimidation, and concentration in the shop today didn't leave room for camera work. And second, there was nothing new to show. Everything I know about gear making was learned on this forum. Many thanks to those who took the time to post such detailed descriptions of the process and whose informative posts gave me the courage to give it a try. Some of us old dogs can still learn a trick or two. 

I would like to thank individually, those whose contributions helped, but I can't. They are many and I would hate to slight any one by leaving them out but it is the sum total of experiences shared on this forum that makes it so great. A little here, a little there, and before you know it you have the courage to try something really outside your zone of comfort.

To those of you still looking forward to making gears... don't hesitate or trepidate. Just by way of information, these are 12 tooth, 24 DP pinions with a 1/2" face. I did not chamfer the edges because the original gears are not chamfered.

I will get to the 60 tooth gears next week when the material arrives. This project has been slowed down a bit while waiting for equipment and getting it adjusted and fit for use, but it may pick up a little more speed now, or not. I'm not real fast.

Jerry


----------



## Deanofid (May 25, 2010)

I can tell you're happy, Jerry! You should be. 
First gear is like first kiss. You know it's done all the time, but until you get your first one, it seems 
mysterious. Before you know it, you're making babies, or engines, as the case may be.

Welcome to the (totally non-exclusive) club!

Dean


----------



## Maryak (May 26, 2010)

Deanofid  said:
			
		

> I can tell you're happy, Jerry! You should be.
> First gear is like first kiss. You know it's done all the time, but until you get your first one, it seems
> mysterious. Before you know it, you're making babies, or engines, as the case may be.
> 
> ...



Great work Jerry. :bow: :bow: babies or engines ??? I'll let you decide which is more fun. ;D

Best Regards
Bob


----------



## Blogwitch (May 26, 2010)

I love this sort of post Jerry. Just seeing how you are going about it gives inspiration to almost everyone.

I think you now have the gearcutting bug, seeing as how easy you found how to do it, and when people see how easy it was for you, maybe they will have a go as well.

Once you get over that first horror stage at what you are going to try, then finding it holds no fears at all is like most other machining operations we do.

Very well done indeed, and I will be following with great interest.


Bogs


----------



## Captain Jerry (May 26, 2010)

Dean, Bob,

Baby making and engine making are not quite the same, at least until my little engines start making their own engines. There may be other differences as well, I forget.

Bogs,

Thanks for the encouragement. If my efforts help someone else to advance their skill just by trying something new, that's great. 

Jerry


----------



## kcmillin (May 26, 2010)

Great Work on the gears and cutters. I am very interested in this project, and am excited to see more.

Kel


----------



## Cedge (May 26, 2010)

Jerry
I know the fear and the elation...LOL. I cut my first gears on my last engine project and sweated bullets. Congrats on a successful adventure. The gears look great!! 

Now, if I can figure out all the angles, my next gear cutting will find me doing bevel gears with the single tooth cutter. I've really gotta make up some hobs one of these days. 

Steve


----------



## Captain Jerry (May 26, 2010)

Steve,

If you do miter gears with a special twist as you always seem to do it will probably turn out to be a spiral bevel gear, with flourishes.

Today I made a startling discovery. It takes 5 times as long to make a 60 tooth gear as it does to make a 12 tooth gear. Go figure! I made the 60 tooth gear out of 3/8" aluminum for practice and to work out some dimensions and clearance issues on the clutch mechanism before committing thirty dollars worth of brass an to make sure I understood the dividing head process.   1. Table right to cut the tooth. 2. Table left to clear the cutter. 3. Mill motor off. 4.Open the RT lock. 5. Crank the RT. 6. Advance the plate quadrant. 7 Mill motor on. 8. repeat 60 times.

Its kind of like drinking tequila shots with salt and lemon. 1. Lick the salt. 2. drink the tequila. 3. Suck the lemon. After a while, it is easy to lose your concentration. No big deal if you get the salt and the lemon in the wrong order. I doesn't affect the outcome. I'm not sure what happens if you screw up the gear making order.

Here is the process under way:












Here is the finished gear:






The gears mesh nicely. They seem to run together smoothly. And the centers are exactly 1.5" apart as planned. This is important because there is no provision to adjust the shaft locations on the donkey frame. I needed this dimension confirmed before proceeding with building the base and hoist frames.

The hoist gear is recessed to mount the clutch mechanism that drives the hoist drum from the gear. I will get to that soon.

Jerry


----------



## Captain Jerry (May 28, 2010)

I may not be the most organized poster on this forum. If it looks like I'm just jumping around willy-nilly, I plead guilty. On the way to the shop this morning I'm thinking that now that I have confirmed the between center spacing on the gears, I should go ahead and finish the base and frame. I could locate all three shafts and get the bearings in place.

It didn't work out that way. I'm sure that I have two pieces of TGP 1/4" steel rod set aside for this project but it was not to be found. It will turn up but now what do I do today. A little voice in the back of my head said "Why do you keep putting off thinking about the clutch?" Once called out, I could no longer avoid the clutch.

Here's the problem. Lots of fiddly little parts.  The way a hoist works is not all that obvious, so if you haven't thought much about it, I'll run through the basics.

When the engine is turning, all shafts are turning. The pinion gear is fixed on the crankshaft. The pinion gear meshes with the two big hoist gears which are fixed to their respective shafts. These three shafts run in bearings on the hoist frame. The pinion shaft and the main hoist shaft are mounted on the same "A" shaped upright, hoist shaft at the top of the "A" and the pinion shaft low on the front leg of the "A". The front hoist is on top of a separate frame that bolts to the main frame. The capstan drums on outside of the left side of the hoist also turn whenever the engine is turning.

The hoist drums do not turn unless the clutch is engaged which connects the drum to the hoist gear. Otherwise, it freewheels on the shaft on another set of bearings.  If the brake is engaged or the pawl set, the drum is stationary with the shaft rotating inside the drum. The brake is a strap around the outside of a brake drum. The pawl can be set to engage ratchet notches in the edge of this drum. The inside of the brake drum is a clutch face. Friction shoes are mounted on the inner face of the hoist gear and when expanded or pushed outward by the clutch mechanism, they bear on the inner face of the clutch/brake drum causing it to rotate under operator control.

Larger hoist have separate brake and clutch drums at opposite ends of the hoist drum so that clutch friction heat doesn't affect the brakes but on small hoist such as this they are one piece.

Here is a picture of the clutch linkage:






On the prototype, each drum has four clutch shoes and you can see the adjusting nut on each linkage arm and the spring which forces the friction shoe away from the clutch drum when the lever is released. To build this in 1/10th scale would be like building a pocket watch. Too much for me.

My approach will be to design a linkage that retains the principal but is simplified to buildable proportions. I will use a two shoe design (half the part count) and a single common spring.

I get nervous when writing long descriptions like this. Laptop batteries and fat fingers have blown away some posts in the past so I'm going to post this now and continue a new post.

Be right back.
Jerry


----------



## Captain Jerry (May 28, 2010)

Here is the two shoe version in Alibre'.






Above is disengaged, below is clutch engaged, pads pushed outward.






It works the same and is a lot simpler but still very small parts, the smallest I have ever built. Here is the results of today's efforts. The gear is my test aluminum gear because there is still room to screw it up.:






The first step is to cut the openings in the gear web. The mechanism is on the outside, and the shoes will fit on the inside when they are installed. The rotary table in use, and I now understand the limited "Z" axis problem. I learned from this exercise that the openings need to be longer to allow full and free movement.






I spent a lot of time with small pieces of brass in the toolmakers vise and an 1/8th inch end mill. The next pic is of the back side of the gear with the linkage showing. The clutch friction material will attach to the links showing through the gear.






Dinner is on the table, gotta go, more latter.

Jerry


----------



## ttrikalin (May 28, 2010)

This is one of the most enlightening posts I've read. 
thank you. 

beautiful work.

tom


----------



## Blogwitch (May 29, 2010)

Jerry,

Like most things, when going to a smaller scale, they can't be directly scaled because of what you found, things become excruciatingly small, and of course, in that small size, they will not work like the real thing, they are not 'man enough' for the job in hand. 

This is where artistic licence comes in, just like you have done, and made it so that it will function the same as full sized, and what a great job you have done with it.

Excellent work indeed.


Bogs


----------



## kvom (May 29, 2010)

Great thread.

When cutting the large gears, did you cut full depth for each tooth? I thought you were going to gash first with a slitting saw, but the pics look as if you finished each tooth before starting the next.

This model is going to be special wheen complete.


----------



## Captain Jerry (May 29, 2010)

Tom,

I'm glad you find this enlightening. This has been a huge learning process for me as well. Lots of time spent investigating and planning.

Bogs,

Thanks for the kind comments. This is what I enjoy most about this hobby, making thing that work. There are so many ways to do it. Simple ideas turn into complex solutions, for example take "Piston pushes rod, rod turns crank, turns shaft, turns flywheel" is a simple idea but the work displayed on this forum just touches on the countless ways it can be done. Great fun!

Kvom

I did cut the big gear in one pass. I made two passes on the first pinion because I wasn't sure what to expect. The second pinion was cut it one pass. The cutter for the pinion actually removes more material in one pass than the big gear so when I got to the big gear I was pretty sure that I would be OK. 

Its a good thing because when I got all set to make the first cut on the big gear, I found that I was at the end of the "Y" travel on the mill. I couldn't have cut the gear in two passes if I had wanted to. Fortunately, I had scribed a mark on the face of the blank to indicate the tooth depth and the tip of the cutter was dead on the line! If I ever have to make a bigger gear, I'll have to rethink the setup.

I don't think that I would try this on anything hard like steel.

Jerry


----------



## zeeprogrammer (May 29, 2010)

Awesome Jerry.
A very interesting thread. Very enjoyable.


----------



## Deanofid (May 29, 2010)

Good going with the larger gear, Jerry. A very neat way you figured out how to set up the clutch and shoes, too. Looks very nice!

Dean


----------



## Captain Jerry (Jun 2, 2010)

Tomorrow, the UPS truck will bring about $40 worth of brass for the hoist gears and the brake/clutch drums. I hope to see some real progress now. I have been getting to know the ins and out of the rotary table and I have just one question about it. 

Why does everything that seemed impossible before, now seem to be possible . Really, How did I get by without this thing. You guys that have one know what I'm talking about. If you don't have one it should be your next purchase, without a doubt. I bought the $159 Grizzly 4" with dividing plates and I thing it is a lot of bang for the buck. As you should expect, for this price, you will have to spend some time cleaning, filing and polishing, but the end result is very usable. The only real problem was the mechanism that locks the eccentric barrel that is used to adjust the backlash int the worm gear. It came in contact with the lip on the housing before it drew up tight. A small brass washer raised it above the lip, gave it more working room and made for smoother operation.

I roughed out the A frames and the shaft bearings today. I have decided to use oillite sintered bronze bushings throughour. Verry rough but it begins to take shape. The frames and the bearing caps still need to be profiled. 






The purpose of this exercise is just to confirm the relative locations of the two shafts and the meshing of the gears. I don't know what I was worried about. No problems. The gears mesh nicely and the shafts rotate smoothly. Here's a video:






Just finger powered but its progress.

Jerry


----------



## Cedge (Jun 2, 2010)

Jerry
I'm really enjoying following this build. You're doing a fantastic job!!

Steve


----------



## SAM in LA (Jun 2, 2010)

Jerry,

Your Donkey is really moving along.

It won't be long before we hear it braying.

SAM


----------



## Captain Jerry (Jun 3, 2010)

Steve and Sam,

Thanks for the interest in this project. I feel like it is beginning to come together even there are many more challenges.

The UPS truck arrived with my material but it was to late in the day to do much more than unpack it. I only wanted enough brass for the gears and the drums, but as usual, they sent way more than I needed. By the time I have chipped of the excess, the weight will have been reduced to about half what it is now.






Hopefully I will begin the chipping process tomorrow. I don't work nights.

Jerry


----------



## Deanofid (Jun 3, 2010)

The assembly picture and finger power look great, Jerry. For a fellow who's never done this stuff,
we'd never know it!

Dean


----------



## don-tucker (Jun 4, 2010)

This is a brilliant post,thanks for sharing,I'm loving it.
Don


----------



## Captain Jerry (Jun 5, 2010)

I think I got a lot done today so this might be a long post. If it gets to be too big, I'll break it into 2 or more bits.

Starting with the hunk of brass above, 3" x 1/2" x 12", I hacksawed it into 4 pieces 2.7" x 2.7" x 2.7" x 2.7" (thats 8 sides). Much easier than sawing aluminum.

Then, using Bogs' flywheel method, I turned it into 4 disks 2.6" diameter.






Then gripping each in the 3 jaw, faced one side, flipped it around and faced the other side and then drilled and reamed a 1/4" hole for mounting on a mandrel.

I then mounted each on the mandrel and took a final cut to bring it to 2.58" (OD for the gear).






Then I setup the rotary table for cutting the gears. First centered a 1/4" shaft in the 4 jaw and checked that it aligned with the "X" axis. There are keys on the bottom of the rotab for this but I had never verified the alignment so I checked. Turns out the keys were good enough.






Then I centered the mandrel in the 4 jaw and mounted one of the gear blanks, and checked again. Good enough.






I then checked the single point cutter that I had used on the trial aluminum gear. The edges seemed sharp but I decided to dress them with a stone before starting.  Mounted the holder and set the tip of the bit on center. I tightedened the "Z" lock, set the depth stop for added security, checked and tightened the "Y" axis clamp, checked and tightened the Rotab hold down clamps and then checked everything one more time. I think I was stalling. Once the first tooth is started, you're committed. I had experience a little "bit creep" previously so before starting, I decided to make a height guage.

I'm called for dinner: I'm back, edited above to add pics.

The height guage is a piece of 1/4" tool steel held in a v-block and set to just touch the bottom of the bit. I can use it periodically to be aware of changes in the bit height.






Nothing left to do but get on with it. Taking full cuts at 2500 RPM, the brass cuts nicely. I cut a few teeth and used the guage to check the height. All is good.






To cut the full 1/2" gear face takes 16 turns on the "X" crank. I'm a little tentative at first but its better to keep the feed steady and full. I find that I can take about 2 rotations per second of feed without complaint from the machinery. By mentally counting, "one (turn) chimpanzee (turn) two (turn) chimpanzee (turn), I can keep an even feed rate and keep my thoughts from wandering.

All goes well and in a little over an hour I have 60 teeth on the gear. 






It meshes with the pinion and I feeling confident so on to gear # 2. 






I think Ive got the technique down pretty solid so I'm going to try to work straight through it. Starting time:






Finish time:






40 minutes from start to finish, 1.5 teeth per minute. I could do this all day.

Two gears and pinion mesh nicely.






Both gears now must be trepanned (I learned this word here, hope I'm using it right. The cut should be 3/8" deep, leaving a 1/8" web between the hub and rim. Hub diameter .75", rim ID 2". Flat bottom, square corners. I'm going to use the same tool that I turned and faced the blank with. HSS, 80 degree pointed, no rake, flat on top, sharp and polished. The tool holder is oriented so that the tool is pointed toward the front of the lathe, with the one edge 5 degrees off of the face and the other edge 5 degrees off of parallel with the axis. It is positioned on the far side of the lathe axis: 






To set the final depth, the compound slide is advanced to the limit of its travel. The carriage is moved up until the cutter touches the face and locked. The compound is then backed off of the face by 3/8". The carriage is then unlocked and moved up until the cutter again touches the face and LOCKED! I can now adjust the depth of cut using the compound and know that I will not exceed the final depth. When it reaches the end of its travel, the depth of cut will be 3/8".

I'm going to take the first cut on the far side of the lathe axis with the lathe running in reverse. My threaded chuck mounting has a clamp that prevents it coming of in reverse. The first cut begins just beyond the hub diameter to a depth of about .025" and proceeds across the face of the gear towards the far edge, stopping before the cut reaches the rim ID point.






Five or six cuts of this depth are made across the face before the cutter is withdrawn from the hole and moved forward to the front edge of the rim just short of the rim ID point. Now with the lathe turning in the normal forward direction, facing cuts are made across the blank.

I hope this is clear because I seem to have lost the pics! Sorry. I can try to get some more tomorrow if anyone needs them. I continue working this way, occasionally shifting from font to back, forward to reverse, until I reach the end of the compound travel. I am at the bottom of the cut. The carriage is still locked. I can now take a penetrating cut at the rim ID and face toward the hub, leaving a square corner. Then I shift to the back and make a penetrating cut at the hub and face off towards the rim (at the back) leaving a square corner and the bottom of the cut is dead flat.

You can see the result in this pic:






Here is another finger power video to show both gears in mesh:







Leaving the carriage locked, I can take the part out of the chuck and replace it with gear #2 and do the same thing to it with identical results. Before taking the gear out of the chuck, I take several facing cuts across the hub, reducing its thickness by .25" below the face of the gear. This is to make room for the clutch mechanism.

The same type of trepanning cut must be made across the face of the clutch/brake drum blanks to make room for the internal expanding clutch friction shoes.

Ill get some shop time tomorrow but no time for evening report. Wife is taking me to a concert.

Jerry


----------



## Captain Jerry (Jun 5, 2010)

A foot note to the above.

A few months ago my wife enticed me to take her and some visiting friends on a little excursion to to a quaint villiage full of antique shops. What a wonderful idea! I was promised a good corned-beef sandwich with a cold beer for lunch if I was well behaved.

At the second shop, I came across a felt lined tin box containing an antique Starret Last Word dial test indicator. I paid $25 for it but I have a feeling it was worth a lot more.

I didn't tell my wife. No sense risking my beer and sandwich reward!

Jerry


----------



## Deanofid (Jun 6, 2010)

You did these up very nice, Jerry. Quite a bit done for one day.
They look great.

$25 for a Last Word is a good deal. They still make them, but they're a lot more than that now!
Thanks for the new post.

Dean


----------



## Blogwitch (Jun 6, 2010)

Absolutely great stuff Jerry.

I really like write ups where I seem to be there with you, enjoying each cut, and how you are using simple little things just to check your progress as you are going along and making sure you don't make a silly mistake.

I find cutting gears and flywheels very relaxing, just as it seems you do, but really it is a job where you definitely need no disturbances. Some sort of mantrap outside the workshop door is needed.

The feeling when they mesh like yours do makes you want to do more and more, just to prove to yourself that you are in fact doing things right. 

That is the wonder of making bits from raw materials.

Because you can !!

Each step learned allows you to go up one rung of the ladder, giving you the confidence to make more complicated pieces.


Bogs


----------



## steamer (Jun 6, 2010)

Hey Jerry,

Great build friend!  Glad someone is modeling the old girl!

If the gear location problem gets complicated, lots of gears meshing together with eachother, wait to finally locate the shafts until after you cut the gears.

Locate and mesh each gear on a toolmakers button, and once they all mesh the way you want, locate the button with your "Last Word" indicator and bore the shaft hole.....

Works real well.

Congratulations on tackling the gear cutting.  Everything is scary the first time, but it is a lot of fun to see them being used after!

Keep it going, I can't wait for the next installment! ;D

Dave


----------



## SAM in LA (Jun 6, 2010)

Jerry.

Very nice gears.

I enjoy reading your narrative.

SAM


----------



## kcmillin (Jun 6, 2010)

Incredible work Jerry. :bow:

I love this method of making gears, and your post is very informative. 

Kel


----------



## doc1955 (Jun 6, 2010)

Very nice set of gears!
Nicely done what did you use for grinding your tooth profile on your cutter?
Now don't laugh when I've done this I have used my machinist hand book photo copied the tooth profile section and hand ground cutter to match I know real precision but it has worked. I was just wondering how you got there.


Again nice set of gears! :bow:


----------



## Captain Jerry (Jun 6, 2010)

Many thanks to those who drop in and leave a message.

Dean, Bogs, Kel, Sam, Dave, Doc,

Your kind comments and words of encouragement are really appreciated.

I'm not often interrupted in the shop. It's 1/4 mile distance from the house keeps all but the truly motivated at bay. 

Doc, the profile that I used for both the gear and pinion came from Rush Gears, Inc. Their website has a utility that lets you input the common parameters and then import a 2D or 3D CAD file with the output.

Jerry


----------



## Jared (Jun 6, 2010)

This is great! Keep it up! Thm: I can't wait to see it in operation.


----------



## kellswaterri (Jun 6, 2010)

Locate and mesh each gear on a toolmakers button, and once they all mesh the way you want, locate the button with your "Last Word" indicator and bore the shaft hole.....

Hi Dave, can,t quite get my head round the above ...the tool makers button bit...are these the buttons with a shaft size hole allowing for positioning and then locked down...a c.o.c. would be a great help.
All the best for now,
              john.


----------



## steamer (Jun 6, 2010)

kellswaterri  said:
			
		

> Locate and mesh each gear on a toolmakers button, and once they all mesh the way you want, locate the button with your "Last Word" indicator and bore the shaft hole.....
> 
> Hi Dave, can,t quite get my head round the above ...the tool makers button bit...are these the buttons with a shaft size hole allowing for positioning and then locked down...a c.o.c. would be a great help.
> All the best for now,
> john.



John,

Will do!...give me a bit while I cook dinner for the kids on the Barbi....... ;D

Dave


----------



## steamer (Jun 6, 2010)

OK

Here we go....

http://i164.photobucket.com/albums/u27/mcandrew1894/toolmakersbuttonexplaination.jpg

Now in the last step, once the button is located under the spindle, or concentric to the spindle, then and only then do you remove the button and screw.  Start the hole with a center drill, then an undersize drill, then if at all possible, bore to a few thousanths undersize.  Then finish with a reamer..

The extra boring step, is to make sure the hole is concentric with the axis of rotation, as drills will "walk" out of position, especially if there is a tapped hole in the cut zone. The boring bar will fix any of that.  The reamer just sizes the hole.

I have a partially finished build of my "Seadog" that shows some pictures of my set up for boring the camshaft bearings, after I located/meshed the gears with a toolmakers button. That may help too....need to get that engine done....too many projects!

http://www.homemodelenginemachinist.com/index.php?topic=3951.0

Dave


----------



## kellswaterri (Jun 7, 2010)

Hi Dave,
Thank you very much for the c.o.c. ...sort of kick starts the old brain again after about forty years  do hope the kids enjoyed the barbie, 
All the best for now,
              John.


----------



## Captain Jerry (Jun 7, 2010)

Dave

The use of buttons might be a good idea but its too late for me to do it the right way. I just set the gear and pinion on short pieces of 1/4" shaft held vertically in v blocks. When they were in mesh, I measured the spacing (to outside shafts - 1 shaft diameter) and it was as close to 1.50" as my cheap calipers could tell me. Since that was exactly what I was hoping for ((2.5DP + .5DP)/2) I was satisfied. I popped a mark where I wanted the hoist shaft and then using dividers, struck an arc across the front face of the "A" frame to locate the pinion shaft.

The front shaft has not been located yet as it will be on axillary frames bolted to the front of the main frame. I won't do that until I have the "A" frames located on the deck with all of the hoist machinery (clutches, brakes, and drum fitted.

I have wondered about the lack of adjustment for these shafts on the prototype. Maybe it is because these are open, slow speed gears with very wide faces. The original uses split bronze bushings and there is no evidence of shims.

Jerry


----------



## steamer (Jun 7, 2010)

No worries Jerry!...It runs therefor you did it right!.... ;D

Pay no attention to me....

Lots of those winches had cast teeth.....lots of backlash, no need to worry much about gear mesh when the teeth are 3 inches tall... :big:

Dave


----------



## T70MkIII (Jun 9, 2010)

Captain Jerry  said:
			
		

> Starting time:
> 
> 
> 
> ...



And I thought I kept late hours. Didn't the neighbours complain? 

Seriously, I am very much enjoying your build, and thanks in particular for your gearcutting details.


----------



## Captain Jerry (Jun 9, 2010)

T70MkIII  said:
			
		

> And I thought I kept late hours. Didn't the neighbours complain?



T70MkIII

When its late over there, its early over here. I have to get an early start before the heat overcomes the small air conditioner in my shop.

There is enough gear cutting information and help available right here on this forum to give a novice like me the confidence to take on the challenge. I am very happy with the results and I hope my experience helps to motivate others to try something a bit beyond their comfort zone. Whatever it is, there is plenty of help right here. 

Jerry


----------



## Captain Jerry (Jun 9, 2010)

I got a little bit done today. I needed to get away from the clutch thing today. Too much tension and I picked up a nasty cold from my great-granddaughter who went visiting somewhere and brought it around to share with us.

The hoist drums are just big spools with the clutch/brake drum as one flange and a plain flat flange on the other end. They freewheel on the shaft waiting for the clutch to move them so today I tackled the core of the spool. Starting with a piece of brass pipe, I turned some brass bushings from some smaller pipe. The shoulders are just to keep them from disappearing down the bore when I solder them.






I may have said this before but soft solder ain't hard!  There is one important trick that must be followed thought. Don't let the heat escape! Even with a very small butane torch and a big piece of brass, you can bring both pieces up to temp and keep them there while the solder flows and the flux doesn't burn as long as you don't let the heat escape through clamps or vises. I try to keep the pieces isolated as much as possible so the heat has nowhere to go. In this case the pieces fit tight enough that I can suspend them from a piece of wire with minimal contact.  If clamping is required, I will make small spring clamps with pointed contacts so they don't take away any heat. Apply the heat to the larger piece, watch the flux flow, touch the solder to a point on the far side of the joint and watch it melt and flow into the joint. You can then take the torch away and touch the solder anywhere around the joint. 






I didn't have enough hands to hold the torch, the solder, AND the camera so that's he best I could do.

The work piece will stay hot enough to flow the solder for several minutes after you remove the torch if you don't let it escape into a vise or a big clamp. You need to leave the pieces undisturbed for a few minutes so they cool and the solder sets before moving them. It works for me so I thought I would pass it on.






When they have cooled enough, I dunk them in water and give them a good wash with detergent and a brush. Excess solder can be trimmed on the lathe or with files. In this case, the pipe that I used for the bushings did not reduce the ID enough so a second set of bushings was made and the process repeated. The second set extends beyond the end of the large core to seat the clutch drum and the end flange.

The clutch disk is a really big piece of brass that I couldn't support on a wire so I stood the assembly on end to keep contact to a minimum. Once the piece had absorbed enough heat, the solder flowed smoothly and there was no hurry.






After it cooled a bit I turned it over and you can see that the solder penetrated the full depth of the shoulder.






The next step was to clean the piece up and true it up in the lathe. That's it for today but I am beginning to feel a lot more confident about the outcome of this project. I seem to do better under a deadline so I hope to post.... No I *WILL* post a video of the donkey running by the end of next week!

Jerry


----------



## Captain Jerry (Jun 12, 2010)

I am now into the inner workings of the clutches. American Hoist & Derrick Co. of St. Paul, Mn, (hereinafter referred to as AMHOIST), used hard maple blocks as friction material in these clutches, and according to their literature, these friction blocks almost never needed replacing. Sounds like a good choice of material. I'll try it.

I don't have any maple handy and I'm not sure that it is the right thing anyway. It's a matter of scale. You can't buy an 1/10th scale maple. All the maple ever grown is from full size maple with full size cellular structure. There may have been 1/10th scale maple trees grown in the land of Lilliput, but I cannot find a website for Lilliputian Lumber so I will improvise. Maple is not available here, but Lowes has oak in a very convenient size (1/4" x 2 1/2" x 24" ) so that's where I'll start. Carefully selecting a piece with vertical grain to minimize cupping, I hacked it into little squares with my hacksaw and pressed it against the lathe chuck face with the live center, just like making a flywheel disk out of aluminum brass.






Oak is very hard and machines easily. The swarf is soft and fluffy and fills up the chip tray pretty quick but the method worked very well. I have spent a LOT!! of time in front of a wood lathe and would never have done it that way before. I was a little concerned that to much pressure with the live center point might split the wood. A proper woodworking approach would use a live cup center but I had no problem at all. The cutting force is so much less that I didn't even need to use double sided tape or anything between the wood and the face of the chuck jaws. Just pressed it up firm with the tailstock.

I used a very sharp HSS bit and it left a nice cut on the edge of the oak. If I were going to apply any type of finish, I might touch it with a little sandpaper but this is going to be a friction face so I burnished it to a hard finish by pressing another piece of wood against it while turning in the lathe. 






The disk was then gripped with the outside jaws and the center was bored to 3/4" ID to clear the hub. I made a few extras. Who knows what will happen?






It looks like I am making a friction pad that will make face contact but I am actually making two pads that will expand radially and make contact on the edges. The pads need to have the same radius as the ID of the clutch drum so it starts out as one disk that fits inside the clutch:






And then gets cut into two separate shoes. Before it gets cut, I transferred it to the mill and cut to dead end slots, .15" deep, at 180 degrees apart.






These slots will be the only connection between the shoes and the actuator plates on the drive gear. I don't know if this will work. I don't want to use adhesive and I cannot figure a good way to use a fastener. I want the shoe to have a sort of floating ability so that outward pressure will seat it against the clutch drum. I had nightmare visions of a loose screw floating around it the works and wreaking havoc, so no screws

Here are the shoes in the clutch drum:






Here are the actuator plates sitting in the slots for visualization only. They will actually sit in slots in the gear and protrude into slots in the shoes.






This is the back side of the gear with the protruding plates. 






The shoes will be flipped over and the slots and the protrusions will match up looking like this






Then the whole thing goes together like this:






In the above pic, downward pressure on the crossbar forces the actuator plates outward through small links that are barely visible. You can refer to an illustration in a previous post for a better view.

*Here is my problem!* The length of these link bars is critical to getting equal pressure and movement to the shoes. The AMHOIST prototype uses a threaded bar for this adjustment link but that is out of the question in 1/10th scale. 

I don't think I have the answer. *Your comments and suggestions are solicited!* I need to get a grip on this. Otherwise my commitment to posting a video of the donkey running by the end of next week is in jeopardy!


Jerry


----------



## Blogwitch (Jun 12, 2010)

Jerry,

The amount of differential movement required is going to be very small.

Could you open out the centre of the main operating bush by say 0.010", and it's locking pin hole in the main shaft by about the same amount, but still retain the pin size in the main bush, so that the operating bush is actually 'floating' around the shaft, but still getting drive thru the pin.

That way, if one of the shoes comes into contact first, the 'float' would still have enough movement to allow the second shoe to come into contact as well. A sort of self centring effect.

I doubt if that little float would be noticeable on an engine of this size.

I hope you understand the method, and it is only a suggestion.


Bogs


----------



## Maryak (Jun 12, 2010)

Jerry,

Is it possible to:-

1. Shim the laggard link.

2. Reduce the length of the slot in the laggard clutch timber.

I realise we are talking small numbers here but.................. just a couple of thoughts to complement bogs suggestion.

Best Regards
Bob


----------



## don-tucker (Jun 12, 2010)

Here's my fourpenneth,once the shoes are applied a few times I feel that they will wear in that few thou,knowing you will have got them as near as damn it.
Don


----------



## steamer (Jun 12, 2010)

To echo Bob and Don's posts, can the assembly be locked in place and machined concentric to the shaft?.....( On the lathe or on a rotary table on the mill...ect)

Once close, it will wear in fairly quickly I think.


Dave

PS.... in looking at the illustrations posted earlier, I think you could machine these.

I would make up a sacraficial face plate ( held in a 3 jaw or what have you but faced and bored in situ just prior to use) 
Mount the assembly on the shaft but minus the clutch drum.  If you make a clamping washer that fits with clearance over the central hub, but clamps the shoes to the faceplate in their natural location ( positioned radially by their own links), then take a slight turning cut on the shoes to make them concentric.  The clamping washer could be held via a custom bolt with a body diameter the same size as your clutch shaft.

Here is the COC.....hope it helps!






Dave


----------



## zeeprogrammer (Jun 12, 2010)

I just had to say 'WOW!'. That is awesome looking.

Sorry I can't help with the problem.


----------



## Captain Jerry (Jun 12, 2010)

Thanks for all the good suggestions, ranging from the very simple to more than I want to think about. I like simple and following Hippocratic principles (first, do no harm), this is my plan,

I'll complete the assembly with proper links and fitted pins. I might get lucky and have it all work without adjustment.



			
				don-tucker  said:
			
		

> Here's my fourpenneth,once the shoes are applied a few times I feel that they will wear in that few thou,knowing you will have got them as near as damn it.
> Don



If its not quite right, it may wear in and seat itself after it has loaded a few tons of logs but I'm not very hopeful. The brass face is as slick as snot and the oak is very hard. My fear is that even if it fits very well, it may not provide a good enough "grip" without a lot of pressure.



			
				Maryak  said:
			
		

> Jerry,
> 
> Is it possible to:-
> 
> ...



I don't know how I would keep a shim in place but going the other way, I could file a bit off the outer end of the brass slider on the proud timber. A few licks might be enough.



			
				Bogstandard  said:
			
		

> Jerry,
> 
> The amount of differential movement required is going to be very small.
> 
> ...



This might be a good fix even if everything fits right on the first try or after filing to fit. I takes care of atmospheric changes in the oak. It is self adjusting within limits. As it is now, the bore in the sliding bush is reamed to a close siding fit but there is no reason that it needs to be that close. Opening it up a bit lets the bush, the links, the plates, and the shoes work as a unit conforming to the fit in the drum, not the shaft. 

It also eliminates the possibility of the bush binding on the shaft over time with wear material from the shoes. That's one of the reasons that I decided to go with oilite bushings throughout. I don't want excess oil contaminating the oak shoes or forming a gunk with wood dust. 



			
				steamer  said:
			
		

> To echo Bob and Don's posts, can the assembly be locked in place and machined concentric to the shaft?.....( On the lathe or on a rotary table on the mill...ect)
> 
> Once close, it will wear in fairly quickly I think.
> 
> ...



I hope it doesn't come to this. It might work but in my shop, there is lots that could go wrong here and great harm could be done!



			
				zeeprogrammer  said:
			
		

> I just had to say 'WOW!'. That is awesome looking.
> 
> Sorry I can't help with the problem.



"WOW" indeed. This is really fun. I keeps getting funner!

Thanks for all the help. I think I am back on track. There will be a video of the donkey running next week! Or maybe the week after!

Jerry


----------



## steamer (Jun 12, 2010)

Fair enough Jerry.

I was at my kids baseball practice this morning and it occured to me.

Just file it.!

Figure out which one is longer, and take a stroke or two off with a fine file....it will remove stock very slowly and can't get away from you.....if you over do one, file the other one.....Once your close, it will wear in to perfection in use....

The solution doesn't always have to be high tech...I need to remember that... ;D

Dave


----------



## Brian Rupnow (Jun 12, 2010)

Jerry---this is a fascinating build, and you are doing a marvelous job. I have never cut a gear, and I would like to try to do so, in fact I will probably try to make the same 60 tooth gear that you made. In the very first page of this thread, you talk about "Dressing a mounted point to a specific diameter" to grind the radius on the single point cutter. I don't really understand what you meant. Firstly, I'm not sure what a "mounted point" is, and secondly---are you talking about somehow turning a grinding stone to the specific diameter required to grind the radius.----Brian


----------



## Deanofid (Jun 12, 2010)

That sure looks neat, Jerry. It's going to be a beautiful thing!

I think Bogs has the solution, if you think about a similar mechanical movement that many of us are
familiar with. Brake shoes in a typical automotive drum brake look completely different in the way
they are actuated, but really, it's similar to what Bogs lays out. In a car, one brake shoe always starts 
the job first, then transfers a small motion through a pivot to get the other one taking up the slack.
Even though the pivot point for that action is not at the centerline of the two shoes, like on your clutch, 
it's still doing what John describes. It equalizes things the same way letting your central bush float 
would do for your clutch. It sounds good and proper to me.

Watching for your next post!

Dean


----------



## Captain Jerry (Jun 12, 2010)

Dave and Dean

I agree that a combination of small steps is the best approach. I was a bit reluctant to proceed until I had a good plan. I didn't want to start down a wrong track if there was a better direction. I think I'm headed the right way now and small adjustments should make it work out in the end. Bogs' fix takes a lot of the worry out of it. It will be a case where a loose fit solves a problem rather than causing one.

As far as comparing it to modern drum brakes there is one characteristic of drum brakes that I want to avoid. In either direction, one shoe of a drum brake set is slightly self actuating. Friction with the drum tends to rotate the shoe outward, applying more pressure, more friction, more pressure ..........  A really good thing before power assisted brakes. (I'm a really old guy) It's not such a good idea on a hand applied clutch. 

Here's why. My first thought was that the operator used the clutch control to hoist a load and used the foot applied external band brakes to control lowering the load. That may not be so. External wrapped brake bands are much more "self actuating" and notoriously "grabby". A careful reading of the AMHOIST brochure seems to indicate that the smooth action of the clutches was used for precise control of lowering. 

In any case, I headed for the shop this morning planning to get on with it. By the time I got all the wood chips vacuumed up, the temp in the shop was approaching 90 deg F. and the AC was losing ground. I got the bright idea of cooling down the aluminum roof with a water hose spray to geve me a chance of getting something done. There is a hose bib attached to the shed and as soon as I opened the valve, I heard the pump start and immediately stop. The pump is about 100 yards from the shed so I grabbed a some tools and headed that way. Sometimes the relay gets stuck and a few knocks will get it going. Not so. The relay housing was packed solid with spider webs and the points had arced and needed filing. As soon as I got that done and got the pump going, one of the float controlled automatic valves on one of the horse watering stations nearby started spraying water everywhere. Failure of a PVC pipe joint was the problem. By the time I got that fixed, I was so hot, wet, dirty, sweaty and pissed off that I decided it was not a good time to work in the shop so I sat on the porch with a beer and the dog and took a nap. Tomorrow may be cooler.



			
				Brian Rupnow  said:
			
		

> Jerry---this is a fascinating build, and you are doing a marvelous job. I have never cut a gear, and I would like to try to do so, in fact I will probably try to make the same 60 tooth gear that you made. In the very first page of this thread, you talk about "Dressing a mounted point to a specific diameter" to grind the radius on the single point cutter. I don't really understand what you meant. Firstly, I'm not sure what a "mounted point" is, and secondly---are you talking about somehow turning a grinding stone to the specific diameter required to grind the radius.----Brian



Brian,

If you're still with me, do it!, You'll like it!

What I call a "mounted point" is a stone permanently fixed to its own shaft, not on a mandrel usually used in a die grinder or a Dremel. Cheap hardware store items less than $2 apiece in various diameters. I use them at much slower speeds in the drill press so that using the little vise and the adjustable table angle, I can get the relief angles right.

The problem, as I saw it after downloading the CAD file from Rush, would be to grind a precise radius on the face of the cutter with only a few degrees of arc to measure. The answer was to pick a stone slightly larger in diameter and dress it down to the correct diameter. A diamond pointed wheel dresser would be nice but I don't have one. I do have a $5 set of "miniature diamond abrasive discs" that do the job just fine. Hand held and pressed against the stone, they bring it down to the needed radius in a hurry. Its easy to measure the stone and then you don't have to measure the radius on the face of the cutter. Just get a full contact arc and you've got it. The relatively slow surface speed of the small stone means heat build up is minimal and you can maintain and control contact for 5 or 10 seconds at a time without burning the steel or your fingers.

You'll work it out. It's pretty easy. I've been following all the threads on making hobs and IMHO this is way easier. I hope this helps. I'm certainly not an expert but I think I've worked out a fairly simple and repeatable method. Let me know if its still not clear.

Jerry


----------



## Brian Rupnow (Jun 13, 2010)

Thanks Jerry---I think I understand now. Perhaps I will start a thread on it.---Brian


----------



## Captain Jerry (Jun 13, 2010)

Brian Rupnow  said:
			
		

> Thanks Jerry---I think I understand now. Perhaps I will start a thread on it.---Brian



Brian

Go ahead with a new thread if you want to, but search the forum for previous threads first. There is a lot of good information. I am a total novice at this, having made four gears so far, and my only source of information was the previous threads and discussions by the more experienced members here on HMEM. I only included the narrative on my experience because it is central to the Donkey project. I'll be glad to join in on your thread if it will help.

Jerry


----------



## Brian Rupnow (Jun 13, 2010)

Jerry--I would be very glad to have you join my thread. I am a complete NOVICE at gear making, so the thread is not intended to tell others how to make gears. It is more intended to show how I would approach it from my perspective as a novice. Any possible help would be greatly appreciated. ----Brian


----------



## Captain Jerry (Jun 14, 2010)

The donkey clutch design underwent some changes today. This is how it happened. There was insufficient force applied to the clutch shoes to get a good grip on the clutch drum.  Effort is applied through the shaft and is translated to outward effort through the links. The mechanical advantage of this type of linkage varies as the sine of the angle that the link makes with shaft. If the links are parallel to the shaft, no outward force is created. As the angle increases the force increases. At a 45 degree angle, the mechanical advantage is 1:1 and as the angle approaches 90 degrees, the mechanical advantage increases dramatically.

The engineer in the office knows this and thinks he's got it covered but when it comes to assembly its not working out as well as he had planned. The machinist takes one look at it and says "that angles too steep. Needs to be flatter."  The engineer says "You're right. I'll go back and make some changes."

The machinist says "While you're at it, you need to reduce the depth of that hub. It's gonna innerfere with the links if you don't"  The engineer says "Right again, but is going to take me some time to make all the changes. I'll get revised drawings back to you in a few days"

The machinist says, "Don't bother, I'll just make it work the way it ought to. You can change the drawing to match later."

The engineer says, "Go ahead, do whatever you think is best"

Its working much better now but the engineer still hasn't got the drawings revised. 

Jerry


----------



## Captain Jerry (Jun 15, 2010)

When I left the shop today, I had to make a side trip to the grocery store. I had a hard time driving, I was so busy patting myself on the back. The clutch works beyond my wildest expectations. With a few changes to the geometry that I will show later, I had what looked like a working hoist clutch. It looked good but needed testing. Here is the test setup.












The shaft is driven by the lathe.

The gear turns with the shaft.

The drum freewheels on the shaft.

The little rod sticking out of the end of the shaft does not turn at all. 

If I press on the little rod, the shoes expand and grab the drum, making it rotate and lifting the weight.

If I let off the pressure, the clutch disengages and the drum freewheels. and the weight falls.

If I feather the clutch, I should be able to hold the weight or lower it under control.

I can't hold the camera, control the clutch, and describe what's happening at the same time so just watch this video:





The amount of pressure required is VERY little. The distance move is imperceptible. Its almost ZEN like. Think "up" and it goes up. Think "down" and it goes down. Think "hold" and you can stop the weight anywhere!

I can hardly believe it!

Jerry


----------



## Deanofid (Jun 15, 2010)

That - is - super, Jerry! It works perfect.

Thanks for the vid. It's fun watching it work!

Dean


----------



## 4156df (Jun 16, 2010)

Jerry,
Sweet!
Dennis


----------



## Blogwitch (Jun 16, 2010)

Marvelous Jerry, it works a treat.

It doesn't matter how you got it to do it, as long as it works.

Bogs


----------



## Maryak (Jun 16, 2010)

Jerry,

I'm sure it works a treat and congratulations. :bow:

I have one small problem PB says it can't find the video.  I will try again in the morning when the wireless link is not so busy and I have a bit more bandwidth.

Best Regards
Bob


----------



## steamer (Jun 16, 2010)

Great job Jerry!  I am glad it all worked out for you. 

Dave


----------



## zeeprogrammer (Jun 16, 2010)

Awesome Jerry. Congratulations.
I can imagine the feeling.


----------



## joe d (Jun 16, 2010)

Jerry

This is coming along really well. I've long been interested in building a donkey engine, watching your version has re-enforced the desire!

Cheers, Joe


----------



## PhillyVa (Jun 16, 2010)

Jerry,

Oh that's great piece of work but, seeing a smile at the end of the video would have been priceless ;D

Regards

Philly


----------



## Captain Jerry (Jun 16, 2010)

Dean, Dennis, Bogs, Bob,
And Dave, Zee, and Philly,

Thanks for watching and taking the time to comment. These little victories are so much sweeter when they are shared. Not many people here in horse country understand the challenges much less the victories.

Here are some of the changes made in the shop that helped get it working. The angle of the links between the floating bush and the sliding shoes needed to be flatter but the hub in the gear face prevented that. The original is on the left, the revised is on the right. Hub removed.






The gear still needs a hub to be stable on the shaft and to provide a mean of securing it to the shaft, so it was moved to the other side as seen here:






The clutch disk had to be modified to provide clearance for this.

With the links at a lower angle, the sliders would not stay in contact with the shoes so I had to revise my position on fasteners. I did not like the idea of a screw inside the clutch working loose and scoring the drum face so I had to run the screw through a clearance hole deep inside the slider and into a tapped hole in the oak shoe. I used a #2-56 machine screw and let it self-tap into a 5/32" hole in the oak which is hard enough to take the thread without stripping.

As to the post from yesterday about the conversation between the engineer (me) and the machinist (me) is that 3D modeling has its limitations. Even if you animate the model and move the pieces, the pieces only move in the manner that you define. In the shop and the real world, they move wherever they damn well please. The real world is full of surprises.

Now that I have this issue licked, I can move on to one of the really ticklish bits that I new early on in this project would be touchy. Translating the 45 degree rotation of the clutch control handle into the linear thrust of the push rod on the clutch. Until now I was not sure what the distance was that the rod would have to move to drive the clutch. I now see that it is almost nothing. I think I can make this work!

Jaw set, clenched fist, and steely eyed, I'm off to the shop to do battle.

Jerry

PS Here's a picture of me smiling, beaming actually


----------



## Maryak (Jun 16, 2010)

Jerry,

Nice self portrait - a bit flashy :

True to form my bandwidth improved this morning and it's beautiful to watch. :bow:

Best Regards
Bob


----------



## kustomkb (Jun 16, 2010)

Great work Jerry!

Go slay 'em.


----------



## Jared (Jun 17, 2010)

I love it! Are you going to post plans when you're finished?


----------



## kvom (Jun 17, 2010)

From that picture, I can only conclude, *"You are Iron Man"*


----------



## Captain Jerry (Jun 17, 2010)

No, I'm not "Iron Man". Here is a picture of me and "Iron Man" together. That's "Iron Man" on the right.


----------



## Captain Jerry (Jun 18, 2010)

Well, into the shop to deal with the clutch lever.  I had a general idea how I was going to work this out, but things changed a bit as I got into it. Several months ago, I posted some drawings that looked good but as I got into it things changed. I planned to use a pin that was in a hole crossdrilled in the actuator shaft. It woud engage slots cut diagonally in a bushing that simulated internal threads. I had a hazy idea how I was going to get the pin in the shaft and the shaft in the bushing and the bushing in the frame, but it got way to complicated to be built.

The final version uses a solid shaft with one 1/16" slot milled across it at 70 degrees. The single pin that provides the axial thrust is disguised as a grease cup on top of the frame in the pictures below. This pin engages the slot and when the shaft is rotated with the handle through an arc of about 55 degrees, the shaft is moved about 3/32" pressing on a pin that moves in the shaft bore, pushing on the clutch bushing and engaging the clutch. Sounds to simple but it works a treat. This is the right hand thread on the main hoist. The left hand thread needed for the front hoist just means that the slot will be milled at the opposite angle. Problem solved.

I didn't take pictures. For one thing inspiration and execution was happening so fast, I could barely keep up. For another thing, the wife was babysitting both of the great grand daughters, so she got dibs on the camera. I brought the results home and took some pictures of the assembly. It may not be ready for prime time but this is a work in progress. My philosophy is make it work, then make it pretty. I know, the fasteners are crappy and the finish is rough and the grease cup is way out of scale, but its progress. Have a look.


























If that,s not enough pictures, tell me, I got more.

Jerry


----------



## Captain Jerry (Jun 18, 2010)

Jared  said:
			
		

> I love it! Are you going to post plans when you're finished?



Jared,

I didn't overlook your question about posting plans, I just forgot to answer. The truth is I don't know. I am not a trained draftsman and although I can produce a 3d model with full motion, and produce a working drawing with the dimensions I need, the part often doesn't get built that way and I don't always go back and modify the model and the drawing. The drawings and dimensions make perfect sense to me but a real machinist might be so irritated by them that someone might get hurt by flying tools.

Still, if someone wanted to build one of these or for that matter if anyone wanted to build any of my other original design (Weeble, or 3 Cylinder Spider) I would be willing to help, including drawing with the above caveat. But lets see if I can get this thing completed first.

Jerry


----------



## Deanofid (Jun 19, 2010)

It sure is turning out to be a pretty little winch, Jerry. 
You're doing well on both fronts.

Dean


----------



## Twmaster (Jun 19, 2010)

Wow what a neat machine. I just spent the last 45 minutes reading the entirety of this thread.

That's just amazing Jerry!


----------



## steamer (Jun 19, 2010)

Looking great Jerry....keep the pictures coming....but building has dibs ;D

Dave


----------



## Captain Jerry (Jul 23, 2010)

Back to the shop. Vacation is over, including a week in the north Georgia mountains complete with an unexpected bear encounter. I should be feeling restored and raring to go but the heat is so intense that it overpowers my shop AC by noon so I'm going to work short hours until it cools off some.


Here is a shot of the crankshaft from the American Hoist Brochure. Note the eccentrics integral with the crank webs.






Here is my version. 






This looks like a straightforward assembly but there are hidden pitfalls. The original shaft has the webs Shrunk to the shaft with a square key. The gear also fits over a square key but it is not obvious how it is secured. I'm not setup to cut internal key ways and there is not room to use a grub screw so I decided to solder the web disks to the shaft. 

That presents more problems. How do I fit the gear and the oillite bushings. I could fit the pieces to the shaft before soldering the webs but I know I will regret that in the future if either needs to be replaced. The solution that I came up with is a two piece shaft. The shaft is milled to 1/2 thickness for a length of 1/2". I was going to join them inside a collar but there is the gear which will serve the purpose. What may not be obvious is that the two halves of the shaft are not clamped together. They are jacked apart inside the gear. The grub screw passes through a clearance hole in the gear, threads into one half of the shaft and presses against the other half, forcing the two halves apart, griping the gear and making a surprisingly rigid assembly. 






Thanks for watching

Jerry


----------



## PhillyVa (Jul 23, 2010)

Jerry,

That's a really good tip :bow: ....way cool Thm:

Philly


----------



## SAM in LA (Jul 23, 2010)

Jerry,

Very clever.

SAM


----------



## Blogwitch (Jul 23, 2010)

A great solution Jerry, two birds with one stone or should that be grub screw.


Bogs


----------



## Captain Jerry (Jul 23, 2010)

Bogstandard  said:
			
		

> A great solution Jerry, two birds with one stone or should that be grub screw.
> 
> Bogs



Grub screw conservation is everyone's responsibility. I'm just doing my best to be responsible.

Jerry


----------



## kvom (Jul 23, 2010)

If you had taken your pic in B&W, you could have made ppl guess which was which.  :bow:


----------



## Maryak (Jul 23, 2010)

Gerry,

Another great innovation from you. :bow: :bow:

Best Regards
Bob


----------



## Deanofid (Jul 23, 2010)

Now, *that's* model _engineering_!
Nice job, Jerry.

Dean


----------



## Captain Jerry (Jul 23, 2010)

Thanks to all who are following this build and special thanks to Dean, Bob, Kvom, Bogs, Sam and Philly for taking the time to respond. What I enjoy most about this hobby is the small AHA! moments when a surprising solution jumps out at you. It is also great to be able to show it to an appreciative group of model engineers around the world.

There are lots of challenges remaining. In spite of the fact that I have built several engines in the past, I have never built a conventional double acting cylinder with a D-valve. I have no plans so I have to work out all the details and dimensions myself. Not really difficult if you know how but I don't. The interactive Zuener diagram written by Charles Dockstader has been getting a real workout and I think I've got a pretty good set of dimensions worked out.

The cylinder has a .625" bore and a 1" stroke in keeping to 1/10th scale. 

The eccentrics have a center offset of .0935" which gives a valve travel of .1875"

The steam valve slots and the exhaust ports slots will be 3/32 (.0934)" wide wit a 3/32" flat between them.

The valve cavity will be .282" wide and the valve plate will be .470" wide.

These dimensions produce no lead, no lap, 100% cutoff. There is no expansion and no compression.

The engine will run on compressed air.

Would performance be improved by tweaking any of these specs?

Thanks in advance for your suggestions.

Jerry



Edited to correct loose decimal position and to correct eccentric throw. (JLG)


----------



## cfellows (Jul 23, 2010)

Just discovered this thread. Great build Jerry! That is some really fine work.

Chuck


----------



## Blogwitch (Jul 24, 2010)

Jerry,

The engine you are designing might do a little better if you make the bore somewhat smaller, 6.25" is a little on the large size. scratch.gif


John


----------



## don-tucker (Jul 24, 2010)

Captain Jerry  said:
			
		

> The cylinder has a 6.25" bore and a 1" stroke in keeping to 1/10th scale.
> 
> I hope that is .625 Jerry ;D,shows I am paying attention anyway.
> Don


----------



## ozzie46 (Jul 24, 2010)

This is truly a neat build. Learn something every time I look.

 Ron


----------



## Captain Jerry (Jul 24, 2010)

Bogstandard  said:
			
		

> The engine you are designing might do a little better if you make the bore somewhat smaller, 6.25" is a little on the large size. scratch.gif
> 
> John





			
				don-tucker  said:
			
		

> I hope that is .625 Jerry ;D,shows I am paying attention anyway.
> 
> Don



Pesky little decimals. I'm sure that one moved after I posted. If you guys hadn't caught it, there's no telling where it might have gone.

Jerry


----------



## Maryak (Jul 24, 2010)

Gerry,

I wish the decimals in my bank balance would go the same way yours did. :

For compressed air I can't see any advantage in messing about with anything other than a bit of lead to give some cushioning at the end of each stroke.

Best Regards
Bob


----------



## ozzie46 (Jul 24, 2010)

Jerry; Have you seen this.

http://cgi.ebay.com/Live-Steam-Scal...tem&pt=LH_DefaultDomain_0&hash=item3a5d318ab3

 Ron


----------



## Captain Jerry (Jul 24, 2010)

Bob

Thanks for the suggestion. If I have this right, increasing the lead means that the steam valve starts to open before TDC and this is achieved by reducing the length of the valve slide. If I reduce this from .470" to .460" starts to open the steam valve at about 5 deg BTD but since this is an eccentric operated valve it only open slowly and slightly to ease the reciprocating motion of the piston at TDC. Is that enough?


Ron

Thanks for the link. I had seen the video on YouTube but not the Ebay listing. Interesting but I'm not bidding.

Jerry


----------



## Dan Rowe (Jul 24, 2010)

Jerry,
Reducing the length of the valve with zero lap will give you negative lap.

The lead is altered by changing the angle of advance. This is done when the engine is timed so it will be easy to experment with different amounts, 5 degrees sounds like a good starting place. 

Dan


----------



## Maryak (Jul 24, 2010)

Dan Rowe  said:
			
		

> Jerry,
> Reducing the length of the valve with zero lap will give you negative lap.
> 
> The lead is altered by changing the angle of advance. This is done when the engine is timed so it will be easy to experment with different amounts, 5 degrees sounds like a good starting place.
> ...



Jerry,

What Dan said ;D This means you need some way to move the eccentric sheave from + 90 deg to +95 deg relative to each crank.

If the eccentric sheaves are set in their 90 deg position the other way around the problem is to add a bit, (say 1/64") of exhaust lap to the valves

Hope this helps

Best Regards
Bob


----------



## Captain Jerry (Jul 24, 2010)

Dan and Bob

Direct quote from the AMHOIST Brochure:

"*Eccentrics* cannot slip nor be set wrong - they are an integral part of the crank web."

They make it sound like a good thing. There is no statement of the angle, (its not a technical document) so mine are set at 90 degrees. They could be changed but with some difficulty. I'm trying to get a good handle on all of the relationship in this slide valve mechanism so I have spent a great amount of time playing with Charles Dockstader's interactive Zuener Diagram

If I increase Lead by reducing the valve width, the steam valve opens before TDC but the opposite steam valve is still open. I guess that's negative steam lap (baaaad). On the other hand, I can reduce the valve cavity which provides the cushioning by closing the the closing the exhaust valve before TDC. I guess that's positive exhaust lap (gooood). That's what I will attempt to do.

Thanks for making me think about this a little deeper.

Jerry


----------



## Dan Rowe (Jul 24, 2010)

Captain Jerry  said:
			
		

> If I increase Lead by reducing the valve width, the steam valve opens before TDC but the opposite steam valve is still open. I guess that's negative steam lap (baaaad). On the other hand, I can reduce the valve cavity which provides the cushioning by closing the the closing the exhaust valve before TDC. I guess that's positive exhaust lap (gooood). That's what I will attempt to do.



Jerry,
If the eccentric is fixed at 90 degrees which is proper for zero lap then the lead can not be changed as the angle of advance is fixed at zero degrees. 

Negative lap is not good because at one point of valve travel both ends of the cylinder will be open to supply pressure.

I do not really see the need for lead with a small model engine as the reciprocating forces are small. Lead is needed on a large engine and on large vertical engines it was common to add more lead to the bottom cylinder end to counter the force of gravity.

I think your plan of exhaust lap is a good one. It was common to have zero steam lap on engines built for power like winches or ships steering engines.

My favorite valve diagram is the Bilgram diagram I find it much simpler to construct and visualize than A Zuener diagram.

Dan


----------



## Dan Rowe (Jul 25, 2010)

Dan Rowe  said:
			
		

> If the eccentric is fixed at 90 degrees which is proper for zero lap then the lead can not be changed as the angle of advance is fixed at zero degrees.



Jerry,
That statement was not fully accurate as the lead can be changed with a fixed eccentric by changing the lap. However reducing the lap below zero is never done because admitting steam to both ends of the cylinder at the same time is so wrong.




			
				Captain Jerry  said:
			
		

> I'm trying to get a good handle on all of the relationship in this slide valve mechanism so I have spent a great amount of time playing with Charles Dockstader's interactive Zuener Diagram



I would find Dockstader's Zuener diagram more usefull if the lap and the angle of advance were the slider variables and use the diagram to calculate lead and cutoff. The things you can change in a model are angle of advance and lap and valve travel so to me that makes more sense to make them the user input variables.

I had to try zero lap and lead on a Zuener diagram and the thing goes all flat line, the same thing will happen on a Bilgram diagram.

I really like valve gear discussions because they make me rethink the subject from a different direction.
Dan


----------



## Captain Jerry (Jul 25, 2010)

Dan

Yeah, I agree that the Dockstader diagram seems a little wrongfooted but then It is a big help to me. Not so much the actual Zuener Diagram representation which I do not claim to fully comprehend. I get a better understanding of what is happening by moving the valve position slider and watching the valve edges. It would be even better if the valve position slider showed crank angle in degrees instead of valve position as a length dimension. 

If I had thought to check out this stuff before building the crank webs and eccentric positions, I would probably set about 5 deg of advance angle.

Jerry


----------



## Captain Jerry (Jul 27, 2010)

Today I got to work on the cylinders. This is what I am aiming for:







The cylinders hang outside the frame. They are mounted by bolting the valve steam chest to the deck. The packing gland is not the normal threaded nut. The adjustable part (normally the nut) is a clamp adjusted by nuts on studs 180 deg apart.
There is an extended neck on the cylinder head that supports a bracket that in turn supports one end of the cross head.

The most eye catching feature is the fluted lagging on the cylinder body. This has been a nagging concern since I started this project. I thought for a while that I would just ignore this little detail. There's no way I can do that, so I'll just make the cylinders plain and try to do something with paint. Then Cedge started show impossible stuff on his tandem engine build and that plan went out the window. Nothing replaced it. I still didn't know what I was going to do.

I was working on a valve plate and clamped down on the vise a little two hard and it bowed up in the middle. AHA!

A little layout, a little drilling and milling:











A little clamping and bending:






And I'm almost there. The problem is that with the cutouts the plate doesn't bend evenly. I tried lots of things but what finally worked was to turn a mandrel about 1/8th inch less than the cylinder body and bend the plate around that and then drive the assembly into a piece of PVC Pipe fitting. The next picture shows the plate inside the pipe and as you can see, it is not perfect, still has lots of sharp bends and flats.











But, the PVC provides protection and form and the little hammer provides the persuasion and before long the plate is looking so good I forgot to take another picture in the fixture.

This is where I was when the thunderstorm hit and tree limbs and branches were bouncing off the shed so I grabbed the camera, called the dog, and headed for the barn. 











It ended quickly with no real damage, but by that time It was beer and dogie play time so we called it quits for today. More tomorrow.

Jerry


----------



## T70MkIII (Jul 28, 2010)

A masterful solution :bow:


----------



## Deanofid (Jul 28, 2010)

That looks soo good, Jerry. You really have a head for figuring things out!

Dean


----------



## Captain Jerry (Jul 28, 2010)

Dean and T70MkIII.

Thanks for waching. This was a real triumph for me. I got the method figured out but I was a little off on the proportions. I don't mind remaking a part if I can make it better and the cost is not too painful. Here is the revised part. The width of the flutes was reduced from .375" to .20"  Much closer to the original.






Lot easier the second time around. I also learned that it is a lot easier to clean up the edges of the cutouts with a file BEFORE the piece is bent. Scrap cost less that $1.

Jerry


----------



## don-tucker (Jul 29, 2010)

Thats a great job Jerry,I'm the same,if I am not happy with the finished job I will make another,learning from the first effort.
Don


----------



## zeeprogrammer (Jul 29, 2010)

Wow. Beautiful job Jerry. Very nice solution.


----------



## Captain Jerry (Jul 30, 2010)

I was not real sure how this part was going to work out so I kept putting it off. Somehow the cylinder and the valve chest have to get joined.  Silver solder would be one way but its not the only way. I decided to use soft solder and screws. The main reason I chose this method is its reversible. If I screw something up, and that's very likely, I may be able to recover.

One of the reasons that I hesitated in this decision is that most of you will think it's lack of skill and nerves. I can live with that. HOWEVER...I don't think the integrity of the construction will be compromised. The project is intended to be run on compressed air so temperature is not a concern, but even if it were ever to be run on steam, the temperature will not reach the melting point of the solder. It might reach a temp that would reduce the strength of the joint but I am not relying on the solder to hold it together. After the plate is soldered to the cylinder, the holes for the studs are drilled and tapped into the cylinder. The studs penetrate through the plate an into the cylinder, stopping short of the bore. The solder is more like a gasket.

Here are some pictures. Those are not my hands in the first shot. My hands only look that way when there is a full moon. Those are the hands of my loyal assistant helping me to frame the shot.






The cylinder has been milled flat to a depth of 1/8" to seat the plate.






The plate is soldered, then drilled and tapped for the studs.






The valve plate ...






and then the valve chest are drilled to clear the #2 studs. 






Here it is with the lagging fitted.






I didn't get to the valve cover or any of the steam passages but the sun will come up tomorrow, just like it did today.

Jerry


----------



## SAM in LA (Jul 31, 2010)

Jerry,

I am enjoying your build.

The fluted lagging looks really good.

Thinking outside of the box is working well for you.

Regards,

SAM


----------



## Captain Jerry (Jul 31, 2010)

Sam

Thanks for watching.



			
				SAM in LA  said:
			
		

> Jerry,
> 
> I am enjoying your build.
> 
> ...



Thinking outside the box is necessary when the box is so small. This is my first ever attempt to model from reality and with no plans to follow some of the steps get pretty hairy.

 I had to leave the shop today because the AC was loosing the battle with 100 degree outside so I'm trying to plan the next challenge. The front head has a long spigot with what looks like a hanging bracket. The bracket supports the cylinder end of the crosshead. The spigot also holds two studs that adjust the packing. It looks like it is cast and machined as a single piece! (not including the packing nut).







I would like to make the bracket as a separate piece but I'm not sure it would be strong enough to support the crosshead. The two studs passing through it add to the strength problem. I guess I'll have a go at making it one piece.

Jerry


----------



## Captain Jerry (Aug 2, 2010)

It turned out to be a lot easier than I thought. I didn't get any pics of the process but If anyone really wants to see how it was done, I'll be making the other one and I'll try to get pics. The only real problem is the tight clearances of the packing gland studs. The nut will clear the piston rod, but the corners of the hex hit the rod when turned. Rats!






Jerry


----------



## steamer (Aug 3, 2010)

Captain Jerry  said:
			
		

> It turned out to be a lot easier than I thought. I didn't get any pics of the process but If anyone really wants to see how it was done, I'll be making the other one and I'll try to get pics. The only real problem is the tight clearances of the packing gland studs. The nut will clear the piston rod, but the corners of the hex hit the rod when turned. Rats!
> 
> 
> 
> ...




No Worries....make up some nuts to fit.  The general rule is 1 1/2 times the bolt diameter.....eyeballametrically...it looks like it would clear if they were that size.

Dave


----------



## SAM in LA (Aug 3, 2010)

Jerry,

How about some socket head cap screws. They may give you the clearance that you need.

SAM


----------



## kvom (Aug 3, 2010)

American Model Engineering sells model-scale nuts. Not cheap, but high-quality.


----------



## Captain Jerry (Aug 3, 2010)

Dave,
  Good idea, whittle some stainless down to 1/8" hex,  drill and tap it 2-56, extract the broken tap,  start over, get it tapped, cut it off, ZING!!! :hDe:, look for it on the bench, the floor, swarf bucket, start over, get it right!!!  repeat 36 times. Pause.....thinking.....ZZZZZZZZZZZZZZ!  Huh!! What!! No honey, I'm okay, just a small nightmare. :fan:

Sam,
  In spite of the wrong appearance, my brain keeps nagging, "cap screws, yeah, that's the ticket". I've even thought about counter bored fillister head screws. Either one would be easier to adjust.

Kvom,
  That's the answer. Damn the expense! I'll use them on the bearing caps as well.

The valve rod uses the same style gland. Only smaller. No problem, whittle some stock down to 3/32", drill and tap #0-80......... No honey! Nothings wrong, just another nightmare!!!

Jerry


----------



## Deanofid (Aug 3, 2010)

Ouch. Kind of got your head bit off there, Dave...

Probably not worth mentioning that a pack of 25 scale SS #2-56 nuts is only $7. :hDe:


----------



## Captain Jerry (Aug 3, 2010)

steamer  said:
			
		

> OK guess I won't bother doing that again...



Dave

My most humble apologies, I didn't mean to sound snappy. I forgot to put goofy little smiley faces all over the place to show I was joking. Some guys might be able to do that kind of work and not even think about it. I'm not one of those guys but I appreciate that you might think I am. In reality, I'm way over my head in this project, just scratching to keep it moving. Any indication that someone is watching helps tremendously.

Jerry


----------



## steamer (Aug 3, 2010)

Awe that's alright Jerry.  I would second American Model Engineering Supply in the sunny state of Florida.....Ask for Ron...as KVOM stated, he'll fix you up..

Damn fine man Ron is....good stuff, worth every penny. If your going to put the time into a model such as this....a few bucks for the jewelry is money well spent.

The best piece of advice I can give you....is slow down and enjoy the build.
I know there is some things to get accustomed to...small fasteners for one. Doing it infront of the audience isn't easy either.  Scratch building from nothing is REALLY tough...ALL the engineering has to be done...either up front or in the mix....

Now, It's going well! its looking good, ........have fun with it too...and just keep eating that elephant...one bite at a time.  You'll be fine.


I'll pull my other posts.....you add the funny faces.....deal? ;D

Dave

PS.... I mean it, that is really looking great....stick with it.


----------



## Captain Jerry (Aug 4, 2010)

As promised, some pics of the gland/hanger. I don't throw away small bits of brass. This is the corner I cut off the square plate before turning the hoist gear blank. Next to it is the part hidden inside.











Probably not the way to hold it in the chuck. I recognize that it is putting a strain on the chuck but I was careful not to over tighten the chuck. Its brass, I'm taking very small cuts with a very sharp HSS tool bit. I'm working very close to the jaws so torque is reduced.






When I am working this close to the chuck, I take steps to prevent a crash. With the compound set parallel with the ways, I run the compound to the limit of its travel toward the head. I then move the saddle up to the head and touch the chuck jaw with the cutting tool. I then back the saddle of just a few thou and lock the carriage. I use the compound travel to back the bit out beyond the end of the workpiece. All movement of the tool is with the crosslide or the compound and I can be sure that the tool will not be crashed into the jaws. This might be normal practice, I don't know. It's just how I do it.

A 1/2"OD spigot is turned and faced. It is then spot drilled, drilled through 13/64" ( the diameter of the gland nut ). Then a flat bottom hole was bored using a 3/8"dia end mill to match the depth of the spigot on the cyl head.






Then over to the mill to shpe the lower support leg.










Now there are two.





]

Jerry


----------



## Blogwitch (Aug 4, 2010)

You are doing some really nice work here Jerry. keep it coming.

To get back to the fasteners bit, and my personal view is that having the wrong fasteners on a model can really spoil it. I basically use three different types.

If it is a scale engine, as yours is, I will always try to use scale fasteners, either home made or bought. I will even modify bought in ones if needs be to get the 'look'.

If the engine is only semi scale, say like a lot of Elmer's ones, I try to keep the fasteners within the look of the engine, so I do make a few special nuts and bolts, but mainly scale.

If it is an engine that really resembles nothing, and came from inside my head, I use fasteners of any sort (except that I do hate Philips heads for final finish), as long as it looks neat, and I do try to hide most of the fastenings as well, if at all possible.

One thing I do do though is if buying in fasteners, it pays to do a good search around. I can usually get 100 normally for around the price you would pay for 10 or 20 from a model retailer. It does mean you have a lot in stock, but it also means that over the years, you can build up quite a collection and I usually have what I need at my fingertips, only needing to top up when they start to get low.

BTW, how to make acorn nuts is shown about half way down this post.

http://madmodder.net/index.php?topic=1054.msg9447#msg9447


John


----------



## don-tucker (Aug 4, 2010)

Ok John spill the beans,where do you get fasteners at that price.
Don


----------



## Blogwitch (Aug 4, 2010)

Don,

If you can wait a bit, I was at Stew's this morning and he has found an even cheaper place, and he is sending me the link. I think he just paid less than 2 pounds or about 4 bucks for 2,000, yes that is right, 2K of 2mm nuts. He has also bought a load of cap screws as well. So until I get the link and have a good look about myself, I can't comment too much.


John


----------



## Blogwitch (Aug 4, 2010)

Just had a reply from Stew.

http://www.fastfixdirect.co.uk/

I misled you earlier, they were 2.24 pounds per 2000.


John


----------



## don-tucker (Aug 5, 2010)

Cheers John,Sorry to hijack your post Jerry.
Don


----------



## Captain Jerry (Aug 5, 2010)

don-tucker  said:
			
		

> Cheers John,Sorry to hijack your post Jerry.
> Don



No problem Don. 




			
				steamer  said:
			
		

> Awe that's alright Jerry.  I would second American Model Engineering Supply in the sunny state of Florida.....Ask for Ron...as KVOM stated, he'll fix you up..
> 
> Damn fine man Ron is....good stuff, worth every penny. If your going to put the time into a model such as this....a few bucks for the jewelry is money well spent.
> 
> ...


----------



## steamer (Aug 21, 2010)

Glad it worked out for you Jerry...

One of Ron's lubricators did yoeman service today on my steamlaunch


----------



## Captain Jerry (Aug 28, 2010)

At last, some more progress on the donkey. I haven't been in the shop much lately. Lots of stuff going on around here and I keep losing my concentration. My grand daughter went back to college last week and she took my dog, Pearl, with her. Pearl is really Katie's dog but she couldn't go to school with her for Katie's freshman year, so she became mine for a while. 

Damn dogs have a way of getting to you with their constant attention and complete approval. I'll miss her. I'll miss Katie too but I can talk to her on the phone.

Today I made pistons. The piston rod is 1/8" stainless steel with 1/2" of #5-40 thread. The piston is .625" dia. and .5" long. I don't have any suitable aluminum rod so I decided to make them from a piece of 1/2" aluminum plate. 

First pic is a little chunk of plate hacked of with a hacksaw:





I drilled a little hole in the center for the live center:





Then I mashed it up against the 3 jaw with a slice of 1/4" oak between the stock and the jaws:





This is a slight modification of Bogs' plate flywheel method. The oak provides enough friction that I don't need to use any double faced tape, and I can cut the full length of the part and cut into the oak without damage to bit, part, or chuck:









I left it slightly oversize so i can finish it concentric with the rod. Now that its round, I can mount it in a split collet and drill, counterbore, and tap it.













The counterbore is for the locknut. Its a close fit so if you look closely, you can see that two opposite sides of the nut have a small notch filed in them so they can be tightened with a two pin spanner.





A 1/8" hole in the oak plate lets the assembled piston and rod be put back in the three jaw. I used the tailstock ram to press the piston and plate hard against the jaws before clamping down on the three jaw. The piston was then turned to size and grooves for packing added:










More to come. I think I've got the fire lit again.

Jerry


----------



## Blogwitch (Aug 29, 2010)

Spot on Jerry.

I had never thought of using that method for such small bits.

Now I know I can, I will.

Thanks

John


----------



## Captain Jerry (Sep 4, 2010)

I made the crosshead guides today.

When I started this project, I considered all of the big pieces. If I had looked at all of the little pieces, I might have started on something else. The small parts aren't any harder, just harder. This is the cross head.








Here are some pics of the successful (mostly) processes. My camera doesn't seem to get pictures of the disasters. I have a lot to learn and mistakes are one way to do that.

I started by sawing some chunks of brass to size:





Drilled crosswise for the con rod pin and lengthwise for the piston rod:





Once again, I'm using the tailstock ram and the live center to mash the part against a piece of oak against the 3-jaw chuck. I know, I look like a one trick pony, but its a good trick and it gets around my limited equipment. I don't have a 4-jaw for the lathe and this gives me a way to center the bore when it is not centered on the part. 
part on lathe





I modified the setup by adding a centering pin to maintain alignment. The part is longer than it is thick. Its not like a disk or a flat plate so this is important:





The bosses turned:





The piston rod boss was turned first and then one of the side bosses. When the part is reversed for the second side boss the first side boss sinks into the oak. Here is the pair complete with bosses:





The slot for the connecting rod is milled:





After a little profiling with an end mill and a little hand filling:










Trial assembly:






Thats it for the progress. Now a question for the experienced engineers. Referring to the first pic in this post, you will see two slots cut across the cross head guide between the crosshead and the piston. There is a similar slot across the guide at the far end of the stroke. These slots are probably to prevent a wear ridge from forming at the end of the stroke. But why two slots at the piston end? There is only one slot at the other end. Also not little evidence of wear on the bar. Based on obvious wear at other points, I would have expected to see more wear here.

Jerry

PS

When I started this post, I put some eggs on to boil for potato salad for the holiday weekend. Note: It took longer to write this post than it did for the pot to boil dry and for the eggs to explode!


----------



## Captain Jerry (Sep 4, 2010)

I went back and looked at the picture of the crosshead guide bar and realized that those slots are way beyond the end of the stroke. The crosshead could not reach them so my first guess as to their purpose is wrong. So what are they?

jERRY


----------



## Deanofid (Sep 5, 2010)

That's a headscratcher, Jerry. Those slots don't look like they do anything, but it's hard to imagine they 
just put them there for fun. I don't know how this assembly was mounted or fastened down. Could
they have been for mounting brackets of some sort?

The guides look really nice!

Dean


----------



## Captain Jerry (Sep 5, 2010)

Dean

The guide bar is suspended from the bracket on the packing gland at this end and from a plate that is bolted to the deck plate at the other end. It is attached by one bolt at each location, the bolt passes up through the bar into bracket, a screw really. It is difficult to make out from this photo because of the rust but the bracket is slightly wider than the guide bar and is notched to the width of the bar. The part number of the bar is "E204" and you can see the "4" sticking out from under the bracket. The rest of the part number is obscured because of the viewing angle.

My other thought was that the part might be used on other hoist and the notches were used to locate the bar but I believe that there was only one smaller machine in the series, so why 2 notches and the "E" prefix designates the "Eagle" model.

I used to know some people at American Hoist but they are all probably dead now and of no help.

Jerry

Jerry


----------



## Maryak (Sep 5, 2010)

Jerry,

SWAG............Oil retention grooves for pick up by a comb attached to the Xhead. They can be filled without getting the can munched by the Xhead. ??????????

Best Regards
Bob


----------



## steamer (Sep 5, 2010)

Darn! Bob beat me to it!  ;D

Bob's right....those are "oil cups"  A piece of thin brass cut to look like a comb....which is what it's called attached to the crosshead....would dip into those "cups" and drag the oil across the cross head guide...every stroke....probably why you don't see any wear there....

You're doing a great job Jerry....I like the thinking on the setups..very creative way to deal with the situation......I would say your doing just fine....

If I can find a reference for a good comb design I'll send it along, but there were as many designs as grains of sand at the beach....I would take another good look at the prototype...there might be a remnant piece to look at.

Dave


----------



## Captain Jerry (Sep 5, 2010)

Bob and Dave,

Thanks for the replies. Oil cups, maybe. But according to the brochure, lube is provided by an oil cup on the side of the crosshead visible in the photo. I dug up a pic of the other side where the cylinder is at TDC and the crosshead does reach the first groove so maybe my first thought (wear edge) is right, or a combination of both. This pic also shows the mounting of the guide bar a little better.






Thanks for looking in,
Jerry


----------



## zeeprogrammer (Sep 7, 2010)

I'm enjoying this very much Jerry.
A very interesting project.
Any chance for a pic showing where you are? Some kind of "here's where I'm at"?


----------



## Maryak (Sep 8, 2010)

Captain Jerry  said:
			
		

> Oil cups, maybe. But according to the brochure, lube is provided by an oil cup on the side of the crosshead visible in the photo.



Jerry,

I agree about the oiler on the side of the X head but my understanding was that this provided oil to the underside of the guide and a comb was used on the upper side. However depending where the holes were drilled it could provide oil to both or one or the other.

Best Regards
Bob


----------



## Captain Jerry (Sep 8, 2010)

Zee

Thanks for inquiring. At your request here is a picture of where I am with this project.






Bob

I guess the side mounted oil reservoir could lube both top and bottom. Seems like all the rod deflection thrust would be down so the top bears the load. If the slot is an oil cup it still doesn't explain the second slot (closest to the cyl.) How long would oil last in those slots? I don't know what the crew for a rig like this would be but I doubt there was a full time Oiler. I would guess there would be an Operator, a Fireman, and a Line Handler or Tender with the Fireman doubling as Oiler. Most of the lube points are screw down grease cups which were probably daily. The Xhead and the piston rods look like the only regular oil points.

Jerry


----------



## Captain Jerry (Sep 8, 2010)

Zee

After thinking about it for a minute or two, I realized that you may have wanted to see how the donkey was progressing so here is a current picture of the donkey:






Jerry


----------



## steamer (Sep 8, 2010)

Hi Jerry,

Often times....as I know too well, the engineer was the firemen was the oiler.... : ;D

I wouldn't have used grease on the cross head....attracts too much dirt...definitely oil there.

As to the final word on the subject...we may never know....but a path to the truth lies in the engine itself...who owned it?

What was it used for?.....Your local historical society may have a picture of her in use at some local industry......you'll never know till you look......

Dave


----------



## ozzie46 (Sep 8, 2010)

Captain Jerry  said:
			
		

> Zee
> 
> After thinking about it for a minute or two, I realized that you may have wanted to see how the donkey was progressing so here is a current picture of the donkey:
> 
> ...






   Rof} Rof} Rof} Rof} Rof} Rof} Rof} Rof}
 Now I not only have cookies in my computer, I have cookie crumbs all over it.
 Don't laugh with a mouthful of cookies.

 Ron


----------



## Captain Jerry (Sep 8, 2010)

Had enough of the smart ass?

Sorry. I didn't get to the shop today so these are pics from my archives. Seriously, I will try to get a progress update together on the donkey hoist and engine project in the next day or two.

Donkey Info:

Name: Hoetie.  It makes more sense if you think "windmills" and say the full name out loud. "Donkey Hoetie"
           My daughter has a wierd sense of humor and a literary bent.

Job: Companion.  Horses are herd animals and don't like to be left alone, even when they are sick or injured. 
            Hoetie will keep them company with no antagonism, no running or playing. Just that sympathetic look.

Jerry


----------



## zeeprogrammer (Sep 8, 2010)

That's a fine looking donkey Jerry.

I wouldn't have guessed that was what you were building from all those parts you've made. Very creative. CNC?

 :big:


----------



## Captain Jerry (Sep 10, 2010)

Hi Y'all

Here is an update of the donkey. It actually looks like it is more complete than it is. A lot of the parts are in approximate position but not actually mounted.






















Progress has been fairly slow lately.  I need to create a work plan and stick to it but it is easy to get distracted. There is a lot of design detail that still needs to be done. 3D modeling is deceiving. You can place a part and make it stay in position without really placing a bolt or a screw or a bracket to hold it there. When you actually get around to making the part, it becomes a whole design project of its own. It lots of fun but thankfully, I didn't submit a proposal that I have to make good on.

Jerry


----------



## SAM in LA (Sep 10, 2010)

Jerry,

What an impressive project.

When I try to hurry, it ends up taking me twice as long to finish.

If I slow down a little, I tend to get there faster.

Keep up the good work.

SAM


----------



## zeeprogrammer (Sep 10, 2010)

That is fantastic looking Jerry. Thanks for the pic.
I've been interested in this thread since you started it.


----------



## Deanofid (Sep 10, 2010)

The assembly shot really shows off your efforts, Jerry. Looking great!

Dean


----------



## steamer (Sep 10, 2010)

Looking Great Jerry!


......just one bite at a time.... ;D

You're doing just fine....just have fun with the challenges....

Dave


----------



## Maryak (Sep 10, 2010)

Jerry,

Great progress and great work. :bow: :bow:

Best Regards
Bob


----------



## ozzie46 (Sep 11, 2010)

Looking great Jerry!

  Ron


----------



## Captain Jerry (Sep 11, 2010)

Sam, Zee, Dean , Dave, Bob, and Ron

Thanks for the kind words and the encouragement.  The work continues and slowing down is well within my abilities. I have come to realize that this may be a lifelong project and as such, it is not necessary to hurry. The unforseen challenges pop up and eventually a solution comes along. 

This is my current challenges. The valve rods are bent. I mean they are supposed to be.







The valve bore is not in line with the guide at the outer end. The rod has a flat section at the outer end that fits into a guide on the hoist A-frame with the eccentric strap joined to it just aft of the guide. The offset is just about 1/4". I am waiting for some idea to pop up that will let me make that rod bend and keep everything parallel. It looks like this could be a real bind point.

I would like to follow the original but I am thinking about making a brass angle plate at the outer end to handle the jog. Alternatively, I could put the guide on the inside of the A-frame which would leave the rod straight. I would have to put an offset on the end of the eccentric strap to reach over to the attachment point on the valve rod. No decision yet. Any opinions or alternative ideas?

Jerry


----------



## steamer (Sep 11, 2010)

I would suggest a bending fixture with the correct offset built into it.

Post a drawing, and we can take a look......... 

Don't worry Jerry...It can be fun when you don't know what to do next....roll with it.... ;D

Dave


----------



## Captain Jerry (Sep 11, 2010)

Dave

Here is another view of the rod.






The offset is more obvious here. That is only part of the problem. The flat section at the end is also a problem. The original was probably forged iron. Even if I could hammer a flat on the end of my 5/32" stainless valve rod, there is not enough material to maintain the dimensions. I'll try to post some drawings this evening but for now, I'm off to the shop.

Jerry


----------



## steamer (Sep 11, 2010)

Hi Jerry,

It looks a bit daunting...but I don't think it is really.

Take a piece of stock the same diameter as a _practice_ piece and put the "valve" end + twice the valve travel in a mill vice and bend the other end by hand to the offset required.......

At least you'll know if you need to get more sophisticated....

Dave


----------



## joe d (Sep 11, 2010)

Hi Jerry

Still following along with great interest. for the current bit: perhaps only one bend in some round stock, and solder the other end at the required angle to a correctly sized bit of flat stock for the flat guide?

Cheers, Joe


----------



## Captain Jerry (Sep 11, 2010)

Dave and Joe

Thanks for your interest and suggestions. I will try bending the rod and soldering a flat giude piece on the end but I don't have much faith in it success. There is not a lot of material contact area. Attached is a drawing that I am thinking about. The rod will be threaded and screwed into the bracket. The eccentric strap will be seated on the boss and fastened with either screw or stud.


Jerry


----------



## Maryak (Sep 11, 2010)

Jerry,

Sorry to be a party pooper....but.....I don't think that's the way to go. 

My feeling is there will be to much load on the pin hole in the end of the flat bar and too much flex in the eccentric rod and adapter arm, the result being the eccentric rod and the end of the arm describe an ellipse which would play havoc with the valve timing.

However, I've been wrong before.  Maybe it's worthy of consideration. ???

Best Regards
Bob


----------



## Captain Jerry (Sep 11, 2010)

Bob

Thanks for taking a look and for your poop. ;D

I had thought that there would not be much torque involved. The flat part of the bracket is captured in a guide which should eliminate any side thrust and torque. The purpose of the bracket is just to eliminate any misalignment caused by imprecise bending. Just to be sure we are looking at this from the same viewpoint, here is another drawing with the parts labeled.

Dave thinks that bending the rod will be easier than I think. If I bend the rod, I still have to get a flat piece on the end of it and attach the eccentric strap. I may just be over-thinking (or under-thinking) the problem, or non-problem.

Jerry


----------



## Maryak (Sep 11, 2010)

Captain Jerry  said:
			
		

> Bob
> 
> Dave thinks that bending the rod will be easier than I think. If I bend the rod, I still have to get a flat piece on the end of it and attach the eccentric strap. I may just be over-thinking (or under-thinking) the problem, or non-problem.



Having bent one and having had the "nervous nellies" before I did it. ;D

I can assure you that Dave is correct, (at least in my case).

I've had a look at your drawing and I understand a bit better, (I think). That being the case where I used the term valve rod before I meant what you have termed the eccentric strap and the hole and the transition arm.

Best Regards
Bob


----------



## steamer (Sep 11, 2010)

Hi Jerry,

If I were you.....I would take a piece of coat hanger wire and try it out..do it a couple of different ways...experiment....prove me right or wrong, beat me up call me bad names.... I don't care, but you will then have the information you seek and you will know... 

Just have fun trying.... ;D

Dave


----------



## Captain Jerry (Sep 21, 2010)

Still messing around with valve rod and guide design although not seriously. My wife and I are traveling and visiting friends and family and I won't really be in the shop again until end of next week but that doesn't keep me from noodling about the problem. I may have made too much of the bend when the real problem is the transition from round to rectangular cross section at the guide end and the attachment at that point to the eccentric rod.  

The purpose of the rectangular section is to prevent twist of the valve rod due to the bend and to prevent up/down deflection caused by the eccentric rod. Previous drawings that I have shown have not been very clear on that so here is another one. 






This was a quickie drawing and the rectangular section of the guide is out of scale between the two versions. Also missing is the bushing that guides this end of the rod. Just use your imagination and know that the valve rod is constrained to a horizontal plane with only reciprocal movement allowed by the guide bushing.

On the left is the configuration with the bent rod. If I were a talented welder I might attempt to build up the end of the rod (stainless) and grind it back to a rectangular section. I am not a welder and won't be one anytime soon.

On the right is the design I am leaning towards. It uses a straight rod threaded into a brass transition piece. The threaded part will make valve adjustment easier. The transition piece provides the lateral shift so the rectangular guide section is in line with the outer face of the A-frame where the guide bushing will be and it provides more meat to hold a pivot pin for the eccentric. 

Thanks for your input, Dave and Bob.  This may not be the final solution but it where I'm headed next week.

Jerry


----------



## Maryak (Sep 21, 2010)

Jerry,

I would build it as shown in the photo.

Make a piece of flat with a boss to take the valve rod either screwed, silver soldered or welded into it. Then, dare I say it, BENT, to alignment. 

Reason - you have done such a great job of replicating and scaling the engine and your straight rod seems somehow not right. As my Grandfather would say, "Listen lad, don't spoil the job for a halfpenny of tar." :bow:

Remember free advise is sometimes worth exactly what you pay for it. :

Best Regards
Bob


----------



## steamer (Sep 21, 2010)

Maryak  said:
			
		

> Jerry,
> 
> I would build it as shown in the photo.
> 
> ...





..................ditto...    I would take the silver solder approach....but to each their own.........the original design adds quite a bit of character to the engine.......but either would make it run....

Dave


----------



## b.lindsey (Sep 21, 2010)

Jerry, I hadn't checked in for a while but the whole project it looking great. I tend to agree with the silver soldering approach on the flat end of the valve rod. Enjoy your travels. Coming back to it in a week or so sometimes helps too with a fresh perspective.

Bill


----------



## Brian Rupnow (Sep 21, 2010)

Jerry---I am enjoying this thread immensly. You are doing a great job.---brian


----------



## krv3000 (Sep 21, 2010)

HI bril work


----------



## Captain Jerry (Sep 21, 2010)

OK, OK, OK! I get it! The purpose of this forum is to share ideas and experience and to keep people from doing dumb or dangerous stuff. Sometimes you have to stick to your guns and make your point instead of just saying "that's nice" and letting it go. Thanks, Bob and Dave, for sticking to your guns. You are right. I wasn't commissioned to redesign this engine. I will find a way to do it that respects the original design.

Bill, Brian, and Bob. Thanks for dropping in and leaving a note so I know you were there. Your kind comments are much appreciated.

Jerry


----------



## steamer (Sep 21, 2010)

Hi Jerry,

Hope I didn't come across as a brow beater....wasn't my intent.

I just know you can make that part....

Dave


----------



## kustomkb (Sep 21, 2010)

Your project is coming all great Jerry! Very ambitious and finely executed.

Your shop looks cozy too.


----------



## Captain Jerry (Sep 21, 2010)

Thanks Kevin, glad you are interested. Executions usually occur at dawn and since the Governor hasn't called, I guess the execution is still on.

Not brow beating at all Dave. I really meant it when I said thanks for keeping me on the straight and narrow or should I say bent and crooked. Now that I am committed to a solid rod at the outer end, I have to start thinking seriously about the other end. The only place left for valve adjustment is the nut in the valve slide. The rod end will be threaded #2-56 screwed into a bar in the valve slide. The valve position can be adjusted in 1/2 turn increments of the bar or about .009" which ought to be fine enough but it is the procedure that is puzzling me. If the rod were straight you would just unpin the eccentric and give the rod a few turns or a 1/2 turn and re-pin it. With the flat end of the rod trapped in the guide that will have to be released but that means the adjustment increment is one full turn or .018" which may be a little coarse. No matter what, it looks like fine tuning is going to be a pain in the butt. There may be a better way to design the valve end of the rod but I can't see it yet.

Any suggestions?

Jerry


----------



## SAM in LA (Sep 21, 2010)

Captain Jerry  said:
			
		

> Thanks Kevin, glad you are interested. Executions usually occur at dawn and since the Governor hasn't called, I guess the execution is still on.
> 
> Not brow beating at all Dave. I really meant it when I said thanks for keeping me on the straight and narrow or should I say bent and crooked. Now that I am committed to a solid rod at the outer end, I have to start thinking seriously about the other end. The only place left for valve adjustment is the nut in the valve slide. The rod end will be threaded #2-56 screwed into a bar in the valve slide. The valve position can be adjusted in 1/2 turn increments of the bar or about .009" which ought to be fine enough but it is the procedure that is puzzling me. If the rod were straight you would just unpin the eccentric and give the rod a few turns or a 1/2 turn and re-pin it. With the flat end of the rod trapped in the guide that will have to be released but that means the adjustment increment is one full turn or .018" which may be a little coarse. No matter what, it looks like fine tuning is going to be a pain in the butt. There may be a better way to design the valve end of the rod but I can't see it yet.
> 
> ...



Jerry,

How about using a turnbuckle nut in the middle of the rod for adjusting the length. I believe that you would need to cut both right and left handed threads.

SAM


----------



## Captain Jerry (Sep 21, 2010)

Sam

A turnbuckle is a possibility. The left hand thread is the hangup due to the size (.093" rod dia.) but it is worth some thought. Thanks for the input.

Jerry


----------



## Maryak (Sep 22, 2010)

Jerry,

The back of the valve, assuming it's a D valve, has a 2 grooves along the centre lines in the form of a cross. One groove takes the threaded valve rod and the X groove accepts a nut which can be screwed either way to adjust the position of the valve relative to the ports. That way a normal thread is all that's required.

If it's a piston valve the centre may be threaded and the valve rod screwed onto it. the valve is turned by means of a couple of holes in the top and locked in place with a nut and a copper washer under it, (to seal the piston). 

Hope you get my drift, if not I will try a C-o-C.

Best Regards
Bob


----------



## Captain Jerry (Sep 22, 2010)

Thanks for the response, Bob. The valve is a "D" slide valve and I have built it with a flat bar with a threaded hole that sits in the cross slot in the back of the valve. I used the bar instead of a hex nut because the space between the valve rod and the bottom of the slot meant that a normal nut would not fit. I also thought that using a bar that could not turn would eliminate any creep in the adjustment without needing a jam nut. I also thought that the bar would keep the valve square to the rod. I may have out smarted myself (easy to do). I guess I shouldn't worry about creep with a tight fitting 56 TPI thread so I need to see if I can fit a nut in place of the bar. There is not much space between the valve cavity and the slot.

Jerry


----------



## krv3000 (Sep 22, 2010)

HI jerry its agood billd  regards bob


----------



## Captain Jerry (Oct 1, 2010)

Hi Y'all

I'm back from my travels and into the shop. Long drives ( 12 hrs Florida to western Tennessee) gives a lot of thinking time while my wife naps, so when I got to the shop this morning, I had a plan. It mostly worked. Here is the result:







The piece on the right is the trial piece and it includes the necessary bends and the attached pivot for the small end of the eccentric rod. The piece on the left (and the one that I will finish tomorrow) will be left straight until the final length can be worked out. The straight one shows how close the hole for the pivot is to the joint end of the rod and the bar. The hole is drilled and tapped for a #4-40 screw. The hole for the screw is the same diameter as the valve rod and it is only about .100" from the end of the bar. I would have had to use a #2-56 thread if I tried to screw the rod into the bar and I don't think it would have been strong enough, even with loctite. There might have been enough material for a good silver-solder joint but I wasn't real sure so this is how I did it:































How about that for stress relief? Not the steel, ME! There is something really relaxing and soothing about heating a piece of metal till it glows and then whacking the crap out of it with a hammer. A few cycles of heating and whacking and I was feeling pretty relieved.

With the two tiny little torches you see, I could not get the metal to the white heat needed to weld the joint, but with the red heat, I was able to reduce the thickness of the flat steel by about 1/3 which makes me think that the round rod was also flattened and deformed in the hole forming a really good mechanical bond. 

A little work on the mill brought the bar to final size and then it was drilled and tapped for the pivot and my mother's brother is Robert.

I'm going to relax with a little Jack Daniels (I've been to Tennessee).

Jerry


----------



## steamer (Oct 1, 2010)

Good Show Jerry!....beat that sumbit*@#&^ into submission! ;D

I knew you'd do it......... ;D

Looks great from here my friend....keep at it....and a karma for thinking about it and taking a chance..cheers!

Dave


----------



## Captain Jerry (Oct 2, 2010)

Thanks Dave. As usual, the things you worry most about don't seem so difficult after you get through it. And I learned something new in the process. I would say that is a forgery ;D but it is not, its genuine.

Just a note on the strength of the joint. The rod is 303 stainless and the bar is mild steel. I gripped the rod in the bench vise and grabbed the bar with vise grips and twisted. The joint held, the rod snapped at the joint. I had left no room between the vise and the joint so there was not much room for the rod to flex. I made another using music wire instead of stainless and put it in the vise with about 2 inches between the vise and the joint. I got two full twists in the wire before it snapped. Again at the joint. 

I'm sure I'll find other uses for this technique, mostly because it's great fun!

Thanks for your words of encouragement.

Jerry


----------



## steamer (Oct 2, 2010)

I'm just tickled pink you "went for it"....Really....courage to you.

Dave


----------



## kustomkb (Oct 2, 2010)

Nice work Jerry.

A good bit of heat out of those butane torches eh?


----------



## Captain Jerry (Oct 2, 2010)

Here is a challenge for anyone. Hold a piece of hot steel in one hand. Hold a camera in the other hand. Swing a hammer with the other other hand. AND do it while the red heat is still on the steel. I failed. The pic is a fake.

Jerry


----------



## Maryak (Oct 3, 2010)

Jerry, Jerry, Jerry,

Now that's a hotrod. ;D ;D

Great work. :bow: :bow: :bow:

Best Regards
Bob


----------



## Captain Jerry (Oct 11, 2010)

Speaking of rods, its time to make the connecting rods. I started the process on Friday and fiddled with it all weekend. I have picked up a new term ( new to me) "fishbellied". Since I don't really know the correct proportions for fishbellied rods, I posted a "Question" friday night but the forum was very quiet and I was impatient so Saturday I put a length of 30d steel in the lathe and eye-balled a double taper and then took a piece of mild/merchant steel and worked out the rod end cap. The bushing and the crank pin followed:






I was pretty much satisfied with the results except its the wrong length and the wrong material. The wrong length because I was just experimenting and the wrong material for the same reason. I have a piece of 1/4" OD 303 stainless that is intended for the rods. The rod end cap will come from a piece of stainless steel that I picked up from the scrapyard with no pedigree.

There was nothing really tricky about the rod once I had the right dimensions. I ground a radius on the end of a 1/4" HSS tool bit and plunge cut to just short of final size at the narrow neck on the rod. With the compound set to about 1.5 deg using a protractor. With the carriage locked, I backed the tool away from the chuck using the compound, cutting a taper. I continued backing away from the chuck after the cutter stopped cutting to give me room to advance the cross slide. 

Then I took a measurement at the narrow point, subtracted the final size (.145") and divided by two to get the amount of cross slide infeed. I cranked it in and then using the compound, I advanced it towards the chuck. When it got to the neck, the full radius of the cutter made contact with the shoulder and that all it took. I reversed the piece in the lathe and did the same thing for the other end. The final finished length of the rod is 3.10" and there is a .5" flat section at each end so the distance between the shoulders is 2.10". I hit that with a layout mark on the second taper. I left plenty of stock at either end for the flat and to hold the part while milling the flats.

My small center drill shed its point a few days ago and while waiting for a replacement, I used another approach for outboard support. I gripped a 1/4"ID oillite bushing in the tailstock chuck ad since the stock was 1/4" polished SS, it was plenty of support.






The next step was to mill the flats on both end of the rod. I set the ends of the rod in a pair of "V" blocks to keep the faces in register and then held each of the "V" blocks in the a vice ( I have 2, cheap) on the mill table. The blocks could have been clamped to the table got them up high enough to clear the "V" block clamp screws when milling the fourth side of the flats.






With the flats milled on both rods, it was time to tackle the end caps. The scrapyard SS was in the form of a block 1.25" wide, .75" thick and 2" long. A short excersize session with the hacksaw yielded a piece off of the end that is .375" thick after squaring it up on the mill. Here it is in the vise with the edge finder in preparation for centering the spindle over the long face.






Now i will mill a 3/4" deep slot the length of the piece. I did not want to risk a 1/8" dia carbide bit. To rough out the cut, I used a 3/16" coated HSS bit taking cuts of .050" with lubrication. Here is the first pass.






I did not like the performance of the 4-flute bit so I switched to a 2-flute bit. It doesn't get much use so it is probable sharper and the chip clearance should be better as the slot gets deeper.






Much better. Now its just a lot of cranking and cleaning. Once I got to the final depth, I switched to a 1/8" carbide bit and increased the RPM and brought the slot to final width with fine cuts.











I have to go watch "The Event" (American TV). If I miss the start, I'll never know what they are talking about. I'll be back after 10:00 o'clock.

Jerry


----------



## Captain Jerry (Oct 11, 2010)

The TV show is over and I'm back.

After checking the fir with the rods, it's just a matter of taking four slices off of the piece, fitting the bushings, which are split square bronze bushings. At this point, I seem to have stopped taking pictures. It got a little bit fiddly and I just forgot. This is where I am now. 






I'm not real happy with the bushings an I may remake them. If I do, I'll try to remember pics. Next is to finish the bushings, fit them to the crank pins and then fit the rod end retaining bolts and pins.

Jerry


----------



## Maryak (Oct 12, 2010)

Jerry,

Very nice rods. :bow: :bow: (one for each).

That's 2 things new to me. Fishbellied - I've made them but didn't know they had a name. The method of mounting the bearings at each end of the rod is a new one for me as well. Maybe it's a USA thing.........I've never seen it on a British engine but perhaps that's because there are many things I've never seen. ;D

Best Regards
Bob


----------



## steamer (Oct 12, 2010)

Yes a USA and British style....difficult to make in small sizes....

Very popular in small sizes as they were easy to "take up" on.

Very Well Done Jerry!

Keep with it buddy, ya doin fine!

Dave


----------



## Brian Rupnow (Oct 12, 2010)

Very nice work Jerry. I had never ran across the term "Fishbellied" before, untill reading it in your thread.---Brian


----------



## Captain Jerry (Oct 12, 2010)

Thanks for the encouragement, Dave. I'm learning to take enjoyment from the small details and challenges and not hurry to a conclusion. This is an example. The rods became the project.

Bob, I didn't know "fishbellies" either but all of a sudden it popped up in several unrelated posts and even on another forum. The rod end is an interesting detail. What Dave says about "easy to take up on" explains the wedge in this pic of the original:






You can see the top of the wedge is slightly mushroomed from hammer taps. These bushings look almost new, with no evident wear. Probably replacements. The AMHoist brochure describes the rods as follows:

  "Connecting Rods: Steel, finely finished. End caps securely bolted. Cylinder heads cannot be wrecked"

I have seen cylinder heads "wrecked" when a conventional rod end cap comes loose and the crank journal contacts the shoulder of the rod. This makes the effective length of the rod increase by half the journal diameter and jams the piston into the head. I can't see that happening with this design. Good design and good looking too.

Jerry


----------



## 4156df (Oct 12, 2010)

Jerry,
Just letting you know I'm still following your build and learning a lot. Wish there was something I could contribute other than saying, "Well done!". I really appreciate the detailed photos.
Dennis


----------



## Maryak (Oct 12, 2010)

Aha,

The full size picture explains the rod end. It's known as a "block strap gib and cotter."

20/20 vision is known as hindsight. :-[

If one wanted to join the RAN as an engineer artificer back in the 50's 60's. The entry exam was to make one using a lathe, shaper and hand tools plus an oxy set hammer and anvil to form the strap. Time allowed 24 hrs, tolerance +/- 0.002." 

If you quenched the strap in water the job was kaput as it was impossible to stress relieve the bend once you started machining and it sprang all over the place. The ones who usually passed the entry were the ones who bent the strap first and left it to cool in air whilst they went on to other parts.

I was lucky, when I sat my final I got the dog clutch. ;D

Memories. : : 

Best Regards
Bob


----------



## kjk (Oct 12, 2010)

So much to learn.....

While traveling in September I encountered this engine:

http://kjkretired.dyndns.org/nfld_trip_files/engine.jpg

What is this style of con rod called?

http://kjkretired.dyndns.org/nfld_trip_files/conrodend.jpg


----------



## steamer (Oct 12, 2010)

Ahhh  a mechanical "inversion"

It's the same thing, just done differantly. The taper key is loosened by loosening the square head bolt a bit. Then carefully set the key with your favorite adjusting tool...sometimes called a hammer....and retighten the bolt to lock the setting.....that would have had to be made with a veritical shaper though...so I don't know if that design won the hearts of the accountants....


Dave


----------



## Captain Jerry (Oct 12, 2010)

Bob, thanks for the acknowledgment. So... you didn't recognize a "block strap gib and cotter" rod end from my poor efforts. Maybe when I get the proper split and bored brasses and the clamp bolts installed they will look more like the real thing. I don't think I can figure a way to install the tapered wedge. I'm still thinking about it.

Dennis, I'm glad your watching. Thanks for leaving a greeting. It's hard to know if its worth the effort without some feedback.

Thanks for the link, Pat J. The Porter discussion explains the engineering behind this rod style very well.

Brian, I did a search for "fish bellied" and turned up a wide range of engineering references, from railroad car frames, to bridge girders, to a Chinese engineering website with a paper title "Numerical Evaluation of Fish Bellied Concrete Box Beam", to this post by Steve Whitehall re building the Stuart "Victoria" with fishbellied rods.

http://www.homemodelenginemachinist.com/index.php?topic=10938.0

Thanks for watching, Woodguy. I think Bob, Dave and Pat answered your question.

While writing this a method of making a working wedge to scale has occurred to me. RATS!! I won't get to try it out until next week. I have to leave early tomorrow and head for the boat. I HAVE A PURCHASE CONTRACT IN HAND!! I have to meet with the buyer's marine surveyor for inspection and sea trials. If all goes well, this happy/sad process will soon be over.

Wish me luck... well not luck but a good outcome.

Jerry


----------



## Jared (Oct 13, 2010)

I've been following along, Capt. Jerry. I've been enjoying this greatly. Good luck/outcome on the boat deal. I'm trying to sell a boat, too, but so far 90% of the lookers have been flakes, ("Call ya in a few days!" They never do.) so I envy your strong possibility of a sale.


----------



## Maryak (Oct 13, 2010)

Captain Jerry  said:
			
		

> While writing this a method of making a working wedge to scale has occurred to me. RATS!! I won't get to try it out until next week. I have to leave early tomorrow and head for the boat. I HAVE A PURCHASE CONTRACT IN HAND!! I have to meet with the buyer's marine surveyor for inspection and sea trials. If all goes well, this happy/sad process will soon be over.
> 
> Wish me luck... well not luck but a good outcome.
> 
> Jerry



Jerry,

I know where your at. :'(  It took me 4 years to sell my yacht and that was at bargain basement prices. I wish you every success with your contract. 



Best Regards
Bob


----------



## steamer (Oct 13, 2010)

Happy Sailing Jerry!

Dave


----------



## Maryak (Oct 13, 2010)

Captain Jerry  said:
			
		

> I don't think I can figure a way to install the tapered wedge. I'm still thinking about it.



Jerry,

Yes, very difficult to slot the block and strap at that small size. Perhaps a rod in the end of the block which hits the top half brass with a tapered pin through the block and strap which presses on the back side of the rod. Then again for the running time, bearing load in model format, why not make a false gib using a tapered pin with the exposed ends filed to shape? The bearing wear is not going to be much if it's even measurable.

Hope it's food for thought.

Best Regards
Bob


----------



## Dan Rowe (Oct 13, 2010)

Jerry,
I am watching this with interest because Shay connection rods are the same design with 2 bolts.

I have considered making working ones and the end of the rod only needs a slot cut with an end mill or slitting saw the width of to the taper pin and cut at the taper pin angle. The flat edge of the taper pin rests on the bearing. The slots have to be filed in the strap which will be the hard part.

Bob's sugestion of a filed taper pin would be a lot simpler for a part that is not really needed for a model.

Dan


----------



## Captain Jerry (Oct 20, 2010)

Hi Y'all

OK, I have decided to remake the split bearings. 

Step 1. Mill grooves in sides of brass bar to match bearing strap:







Step 2. Saw of to length ( 1/2 of finished bearing) 8 pieces:






Step 3. Mill slots on 3rd side of bearing halves so that a pair will have groove on all four edges.






Step 4. Test fit pairs to bearing strap:






Step 5. Test fit to con rod.






Step 6 Drill for clamp bolts. The fishbellied rod needed a holding fixture to clear the belly.






Step 7. Mill bearing faces to finished dimension. The faces sit proud of the con rod face by .020"






Step 8. Test fit to Xhead guide and orient to assembly.






Oh! crap!!!

The assembly is 1/2" too long. I thought I had more room in there and got a little careless with the packing gland and crosshead support bracket design. I may be able to get some space if I shorten the Xhead a bit but not much. I could cheat the location of the cylinders a bit but not much. I will either have to get it back in a remake of the head, packing gland, support bracket or the frame. I'm Not! remaking the rods!

Jerry

PS. The sea trial went well. Beautifull day, steady winds, great conditions and the buyer was drooling. The surveyor was satisfied with all systems which worked to perfection. Back to the boatyard to haul out for bottom inspection. YIKES! HORROR! The rudder is broken. A huge crack, leading edge to trailing edge, in the middle of the rudder, open all the way to the core. It was not there the last time I was under the boat in the crystal clear waters of The Bahamas. Obvious impact damage but damned if I know when. Coastal and inland waters of the US are so murky that divers who clean the bottom do it mostly by feel and none had reported the damage.

The buyer is still happy and the deal is almost done but I have to provide him with a new rudder. I'll be busy with that for the next few weeks so further progress will be intermittent.


----------



## kustomkb (Oct 20, 2010)

Looking good Jerry, Sorry about the mix-up.

That's a 1-2-3 block? I had imagined it much bigger.

Nice work!


----------



## Brian Rupnow (Oct 20, 2010)

Jerry---Tough luck!!! Hope you can find a way around it. This must be the "problem month". I've been fighting crankshaft battles while you've been building your rod assemblies too long!!!---I am enjoying your posts.----Brian


----------



## Captain Jerry (Oct 20, 2010)

Kevin

1-2-3 Blocks are all that size. ???  The bigger ones are 2-4-6 blocks. ;D

(It's after dinner and I'm sipping some good Bourbon that my daughter brought back from Kentucky)

The engine is 1/10th scale. The real one is 10 times bigger. There are times I wish I had chosen a larger scale, but I had brass on hand that dictated the 1/10 scale.


----------



## Captain Jerry (Oct 20, 2010)

Brian

Yeah, stuff creeps up on you. The rods are the correct length. They are one of the easiest parts to get a good dimension on from the original. The problem is with the other parts that I winged it on for some of the dimensions but since the rods were built last, If I had checked first, I could have adjusted. They wouldn't be right, but nobody but me would know. ( Read that somewhere)

I'm following your IC build but since I haven't crossed that bridge, all I can do is watch and learn.

Jerry


----------



## steamer (Oct 20, 2010)

Actually Jerry....I'm damn proud of ya. :bow:

You didn't let a tough spot change your direction....just figuired out a way to go through it...and then went for it!

You'll get through this hurtel also...I have faith...because you have faith in yourself...They didn't make a Karma point to fit that one, but I'll give one of the regular ones anyway.

GoodOnYa!

Dave


----------



## kustomkb (Oct 20, 2010)

I thought they were 1.015-2.035-3.069 blocks, in that case mty sense of scale was bang on.

Just kidding, but my first thought was 2-4-6 blocks.

I'll join you with a shot of Wild Turkey. ;D


----------



## Brian Rupnow (Oct 20, 2010)

Steamer is right!!! Thats one heck of a great build, and you get a karma from me too!!!!


----------



## zeeprogrammer (Oct 23, 2010)

Still watching Jerry. Still very much impressed. It's a very nice model.


----------



## Captain Jerry (Oct 27, 2010)

Problem all fixed and I did not remake the rods. I just had to take a little off of the cylinder heads, the packing gland and the cross head hanger and now I have the full rotation through top dead center. You might not notice but the proportions are now much better.






Now that that problem is resolved, I can mount the cylinders in their final position on the base and proceed to fit the x-heads for both cylinder and valve. I did not want to do any of this until I was sure of the cylinder position.

Jerry


----------



## steamer (Oct 27, 2010)

Way to go Jerry....Keep at it, your getting there!
Dave


----------



## Maryak (Oct 27, 2010)

Nice going Jerry, :bow:

Methinks this is going to be very nice.

Best Regards
Bob


----------



## Brian Rupnow (Jan 27, 2012)

Jerry--Has this project been discontinued? You made such marvelous progress for the longest time, and then it kind of faded away. I am contemplating a similar build and after watching a number of videos of steam donkey engines on Youtube I realize that there were many different types and configurations of steam driven donkey engines.----Brian


----------



## Captain Jerry (Jan 27, 2012)

Brian

This project is packed away in a drawer, waiting for an increase in skills. It was my first attempt to build a model to scale. Up till then, I had just built little machines that worked. There is a big difference. I found that there were some parts that would be needed that I had no clue as to how I could make produce. I'll get back to it some day.

I had thought that the internal friction clutches would be a big challenge, and they were. I was able to design a working mechanism without regard to scale because the clutch shoes are hidden inside the drum. The external, contracting brake bands brought me to a halt. They are exposed to view and I could not find a good method of production or the right material or the right idea.  I sometimes find that a problem like this will solve itself if I don't concentrate too hard and a new approach will come to me in a dream.

There have been 423 nights since I put this away and more than a few ideas have come to me in my dreams but I'm not hearing anything from the donkey. Maybe this little reminder will nudge something into action.

Thanks.

jerry


----------



## Brian Rupnow (Jan 28, 2012)

Jerry---I am going thru your post in detail this morning, and when I try to watch any of the videos I get the message that they are password protected. Can you possibly share the password with me please.----Brian


----------



## Captain Jerry (Jan 29, 2012)

Brian

Thanks for the heads up. There is no need for these to be protected. That must have happened when I wasn't looking. Photobook has done that before. I will remove the protection if I can figure out how.                   20576

Jerry


----------



## Captain Jerry (Feb 3, 2012)

I thought that I had resolved the 'protected' status of videos on this thread but this morning, I was reviewing the status of this project and because I had not logged in to Photobucket, I found that the videos were not available. I also found that some of the links were broken and I think that I have them all fixed now. If you find that they are still unavailable to you, please post a 'Heads up" and I'll keep after it.

Here is a new video of the main winch with the clutch in action. It is being driven with the headstock of my little Unimat with variable speed control so that pinion shaft rotation is about 200RPM. The clutch is being operated my the operators control lever just as it would be in real operation. It is very responsive and requires only a light touch. It is quite easy to lift, lower, and hold the load without needing a brake, even though I am sure that doing so would be bad practice. Wear on the clutch friction pads would need to be kept to a minimum since the pads are not easily accessible. The entire drum would need to be lifted out of the bearings to separate the gear and clutch drum. Easy to do on the model, 4 bolts and it only weighs a few ounces vs. a couple of tons in the real world.  Excessive slipping of the clutches would surely have been discouraged.





Please let me know if this video is not available to you.

Jerry


----------



## tel (Feb 3, 2012)

Got it just fine here!


----------



## Brian Rupnow (Feb 3, 2012)

Jerry---the video works just fine now. There is something very fishy about Photobucket. I have a paid subscription to Photobucket, have had for a few years now.---And yet---If I go back to look at some of the links I have posted on this forum to various videos I have made and posted, Photobucket opens and a window pops up saying "video not available". I don't know why this is, and I should probably get ahold of photobucket and rag on them, but I haven't.----Brian


----------



## Captain Jerry (Feb 3, 2012)

Brian 

That's the same message that I got, even though the file were intact and in the proper folder. So I edited the posts and inserted a new link. I compared the old link to the new link and they were exactly the same but the new link worked --- go figure. I think the problem is cleared up now.

Jerry


----------



## Brian Rupnow (Feb 4, 2012)

Come on Jerry!!! I can feel your interest starting to percolate!!! I know that you left off this build because you thought your skill level wasn't up to it, but after succesfully building the overcrank single and the vertical table version thereof, I'm sure you have progressed a great deal in your machining abilities. You did such a bloody amazing job up to this point, I think you should carry on with this build. Everyone who agrees with me say "AYE"----Brian


----------



## chuck foster (Feb 4, 2012)

AYE

chuck


----------



## Harold Lee (Feb 4, 2012)

Brian Rupnow  said:
			
		

> Come on Jerry!!! I can feel your interest starting to percolate!!! I know that you left off this build because you thought your skill level wasn't up to it, but after succesfully building the overcrank single and the vertical table version thereof, I'm sure you have progressed a great deal in your machining abilities. You did such a bloody amazing job up to this point, I think you should carry on with this build. Everyone who agrees with me say "AYE"----Brian



I agree with Brian. I would love to see you pick you project back up. You know Brian, there might be more to this Tom Sawyer thing than we thought


----------



## tel (Feb 4, 2012)

Yep, get an AYE from me as well.


----------



## ozzie46 (Feb 4, 2012)

[size=10pt]*  Aye, Aye, Aye*[/size]


  Ron


----------



## nsfr1206 (Feb 4, 2012)

You might as well go for it.


----------



## Captain Jerry (Feb 4, 2012)

Brian, Chuck, Tel, Harold, Ron and nsfr1206, 

Thank you for the vote of confidence. This project has been under the bench for over a year and has needed looking at again. I am reviewing the situation and the status of the work so far. I got the parts out of the drawer yesterday. There are some parts that I am satisfied with and indeed very proud of. There are other parts that don't quite cut it. And there are some parts that just plain stink. Every mistake is an opportunity to learn and I have had plenty of opportunity so maybe I have learned a thing or two.

In the next day or two, I'm going to redesign and remake some of the parts and see if I have learned anything useful. I would really like to get this back on track.
                                                                            20985
Jerry


----------



## larry1 (Feb 5, 2012)

Jerry, Aye, Aye, Great work. larry


----------



## tel (Feb 5, 2012)

> There are some parts that I am satisfied with and indeed very proud of. There are other parts that don't quite cut it. And there are some parts that just plain stink.



 ;D Pretty much normal then, at least for around here!


----------



## Brian Rupnow (Feb 5, 2012)

Great news Jerry. So glad to have you picking up the torch once again.---Brian


----------



## Captain Jerry (Feb 6, 2012)

Just when I thought I knew How this winch worked, I found out something new. Here is a picture of the part where the rotation of the clutch lever applies axial thrust to a pin in the end of the shaft. I have looked at this picture for years and got it wrong. It appears that the part marked here:







Is part of the bearing support stand and that the shaft rotates inside of it. I was wrong. In the next view from a different angle and under different light, it is clear that it is not part of the bearing stand, you can see the fine line of separation. 






It is fixed to the shaft and rotates against the bearing stand or against a bushing. This is critical. When the clutch pin is pushed in, it pushes the clutch shoes out against the clutch drum but some of that force is transferred to the gear face by the sliders, and the shaft wants to move in that direction as well. I knew that there had to be a thrust collar somewhere but I could not see it. So I had done it wrong. I had used flanged oillite bushings at both ends of the drum. They let the drum turn on the shaft, and they transferred the axial thrust to a flanged bushing in the stand at the far end of the drum. It worked, as I have demonstrated, but it was fiddly and difficult to adjust. It also added a lot of friction to the whole thing. It added enough drag that I felt the need to do some testing to be sure that the engine will have enough power to drive the winch at 200/300 RPM.

I had previously used my Unimat in a to drive the winch in trials, so yesterday, I rigged up a more solid test stand with the unimat drive.






Lowest speed with belt drive.






And reduced to about 200 RPM with a router control box. This box does not give good torque at very low speeds. It is easy to stall the chuck between your fingers. Not very precise but it seems to be in the power range of a twin cylinder air engine.

It took a little bit of fiddling to get the spindle and the crankshaft aligned and a little bit more time to get the clutch adjusted sot that it would engage and disengage smoothly. Playing with this thing is so much fun that I spent some time just playing. I noticed that when the clutch was applied, there was some flexing in the base and that the bearing stands flexed outwards as a result of the thrust being transferred through the winch drum. I was able to lift and lower a 5 pound weight with moderate pressure on the clutch lever but the Unimat motor wasn't happy. It would slow from 200 RPM to less that 100 RPM and get real jerky and stall. 

I also noticed an irritating noise from the gears. They have never been run together for more than a few minutes and they had been in a box under the bench for over a year so they weren't bright and shiny. I didn't like the noise and I didn't like the flex so I took it completely apart and put just the pinion shaft and the winch shaft with gear back on the frame. I thought I would let the gears run in with a touch of Brasso and 30weight oil while I scoped out the clutch works.

In just a few minutes, the gears were running very smoothly so I let them run a few minutes more while applying some load with my finger on the big gear. I took them out of the frame and washed them with solvent and reassembled the whole thing for some more observation (playing). Gear noise all gone, smooth as silk. Flex and friction drag still there. I was starting to think that I needed ball bearing thrust washers at each end of the drum but that would be a real lubrication problem. 

The quitting whistle blew so I cleaned up and headed to the house feeling a little a let down. After dinner, I was going through my "donkey" files, pictures and drawings, getting better organized to resume this project when I finally noticed the small separation line in the second photo above. Ureeka! That is the answer. That IS a thrust collar. All the axial thrust is absorbed right there. No transfer to the winch drum or to the bearing stand at the far end. I will still leave the flanged bushings at both ends of the drum to keep it in position but the contact between the flange bushing faces will be completely unloaded, even under maximum clutch pressure.

This morning, I turned up a brass thrust collar soldered it to the end of the shaft. I had to adjust some lengths and clearances but I got it all back together. WOW! What a difference. No flex, and without the flex, the additional friction caused by bearing misalignment as the stands flexed out of parallel was gone. The electric motor slowed only slightly as the clutch was applied, even when I increased the weight to 3 pounds. It worked so well that I played with it for another hour, up, down, float, feather, hold, faster, slower, heavier, lighter and I got the feel of the machine and I was not satisfied with the action.

There is no over-center or knuckle-in action. When the lever is at the full end of travel, the clutch linkage comes almost straight but due to the geometry, it will not knuckle in. It has to be held. If you release pressure, it doesn't immediately drop the load, but it begins to slip and soon disengages completely. There is no quadrant or notches to hold the lever either. On the real one there is a stop at the disengaged end of travel but there is nothing at the full on end of travel.

So I start thinking. I redesigned this part of the machine because I don't think that I can cut internal square threads at this scale (or any other scale). I used a slot, milled at an angle across the actuator instead of a full screw thread, creating a straight ramp instead of a helix. I could file of the end of the slot so there is a straight step at the top of the ramp. So I did.

Now when the pin that acts as the internal thread reaches that flat spot at the top of the ramp, it notches in and will stay there until the lever is pulled back. The action is smooth and positive and subtle. No hint of any binding. I did have to readjust the clutch because of the shortening of the inclined part of the ramp. The adjustment is a real pain because it involves taking the drum out of the stands and making small adjustments to the position of the gear on the shaft. I bet they had a better way. 

Of course they did. Thats is what the threaded hickey is sticking out of the end of the actuator, a clutch adjuster!






And look at the way that clutch lever is clamped around the actuator. It almost looks like a repair by the local blacksmith but it is actually shown and described that way in the AmHoist Brochure. I guess I will have to try to make one. So I did.






I didn't get any pictures of the process because the batteries in my camera had died so I took this after I got home tonight. It's not exactly right, The clamp bolt needs cutting and the shaft should have been tapered and a little longer and a handle should have been turned at the end before it was bent but those are familiar processes, I needed to see what it would take to fabricate the flat, wrapped clamp. It was surprisingly easy. It took about an hour, but I'm slow when feeling my way in the dark. I'm going to do another one tomorrow. Better I hope.

I guess I'm officially back into this. After all, here is the first new part. Stay with me if you don't mind reading incredibly long posts. They won't all be this long but I feel the need for a full explanation when dealing with things that are out of the ordinary. I hope this explanation was understandable, I don't think pictures would make it any clearer, so I'll try to post a sectioned drawing of the winch shaft with thrust collar soon.

Thanks for watching, comments are appreciated or at least tolerated.

Jerry
.


----------



## tel (Feb 6, 2012)

Like the frog on the windscreen - I'm still here!


----------



## steamer (Feb 6, 2012)

......ribbit....ribbit


Dave


----------



## metalmad (Feb 6, 2012)

Me too :big:
Pete


----------



## Brian Rupnow (Feb 6, 2012)

Jerry---Welcome back onboard!!!---Brian


----------



## dalem9 (Feb 6, 2012)

I like it all , keep up the good work . Dale


----------



## Captain Jerry (Feb 6, 2012)

A small crowd is assembling. I hope I don't let you down.

Here is the complete hoist drum assembly in cross section. I think it is better than a picture because you can see the works. The thrust collar (yellow) is soldered to the shaft, flush with the end. It bears against an oilite bushing (red). The bushing is held in the bearing support and transfers all thrust to the support. Pressure on the end of the pin (red) is transferred to the cross pin (green) which is fixed in the clutch spider (blue) which acts on the links (pink) which expand the friction shoes. There are two oillite bushings internal to the winch drum that let it rotate freely on the shaft and one on the far end of the shaft that is supported by the stand at that end.






This is probably the final design for this assembly.

Jerry


----------



## Captain Jerry (Feb 7, 2012)

Here is the second try at the clutch lever. The cold formed. You gently urge the material from one shape into another shape while it is cold. That means you can whack it with a hammer as many times as you want but no heat is allowed. The no heat thing is kind of misleading. If you take a piece of steel, put it on an anvil, whack it with a hammer a few times and hold it between your fingers and you will get the point.

To make this work, you must chose your material carefully. Not to hard, not to soft. No music wire, no solder. I have found that SOCof works just right. My supplier stocks in rod in various sizes, from about 1/16" dia up to about 5/16" diameter, with several finishes. I prefer the "bright" or uncoated finish. Avoid the galvanized or the really weird glue coated. Strangely it is only available in short lengths, with a flat disk already cold formed on one end and a crude point on the other. The even thickness and regular shape of the cold formed disk is an indication of the material's cold forming acceptance.

For the clutch lever, I chose a size of a little less than 3/16" diameter about 3.5" long, Identified as size 16d. The first operation is to remove the disk and the point so into the 3 jaw chuck on the lathe to turn them off. Here is the first step:






It is then reversed in the chuck and the point is faced off and the end is center drilled for the live center. with about 1/2" is gripped in the chuck and the other end supported by the live center, a handle is formed at the tailstock end and the rest of the shaft is tapered using a 2.5° offset of the topslide. Here is what it looks like:






The finish is not very good but it will be improved by centerless grinding. That's what it is called when you roll it between thumb and finger while holding against the bench grinder wheel. Sorry, I didn't get a picture of that operation. Its hard to get a good finish while looking through the view finder.

Next is a view of the part positioned over the cold forming die. From here on, the process becomes a little precise. Whack it with a hammer over and over while attempting make the end of the rod flat evenly. There is a little technique involved in hammer whacking. If the part is starting to bend away from you, the near side is getting thinner. Raise your wrist a little. If it is bending toward you, the far side is getting thinner. Lower your wrist a little. Stop when the flat part is about 1/16" thick.

This is what it should look like:






Now the edges of the flat part should be filed to bring them straight, parallel and about 3/16"wide. It is a little easier if the coated with mark-up dye and scribed. Here is the part held in the bench vise with aluminum soft jaws:






and here is what it looks like after filing:






The next step is to bend the flat part into an eye with a 3/16" ID. More cold forming, a custom die is called for. The die is fabricated from a bar of CRS 3/16" thick and 1" wide. A 1/4" dia hole is drilled near one end of the bar leaving about 3/16" material between the edge of the hole and the end of the bar. Then the end of the bar is rounded over with a file. The profile of the bar end should be a full semi-circle. It looks like this standing up it the vise. The length of bar standing above the vise should be about the length of the clutch lever.






This is the part being formed over the die:






What's the hole for? This:






The final closing of the eye is done between the soft jaws in the vise. A 3/16" rod is inserted in the nearly finished eye and the eye is closed around the rod between the jaws. It is hard to get a good picture of this but I tried:






After the eye is formed, the handle is bent 90° to the shaft.

A little filing, a little buffing, clamp bolt (#2-56) and the result looks like this:






Much better than yesterday's effort. I'm satisfied.

Here is a video of it installed on the winch and demonstrating the knuckle in action that I worked out yesterday. When the clutch is engaged, it stays engaged by itself until disengaged. 





And thus ends today's fun.                                                         21520

Jerry

PS: The steel classification of  SOCof indicates Somebody's Old Chevy or Ford


----------



## Maryak (Feb 7, 2012)

Captain Jerry  said:
			
		

> To make this work, you must chose your material carefully. Not to hard, not to soft. No music wire, no solder. I have found that SOCof works just right. My supplier stocks in rod in various sizes, from about 1/16" dia up to about 5/16" diameter, with several finishes. I prefer the "bright" or uncoated finish. Avoid the galvanized or the really weird glue coated. Strangely it is only available in short lengths, with a flat disk already cold formed on one end and a crude point on the other. The even thickness and regular shape of the cold formed disk is an indication of the material's cold forming acceptance.
> 
> 
> Jerry



Very Droll Rof} Rof} Thm:

Best Regards
Bob


----------



## Brian Rupnow (Feb 9, 2012)

Nice handle Jerry!!!! I just read your recent post over a dozen times trying to figure out what was said-----I know its very plain to you. Basically it seems that all you have really changed is that you have installed an outboard collar on the end of the shaft, to bear against the outside head of the shaft support bushing which is "fixed" in the support housing. This takes up all of the axial thrust so that none is tranfered to the winch drum nor to the far end shaft bearing and support. Do I have that right?---Brian


----------



## Captain Jerry (Feb 9, 2012)

Brian

That is exactly right. All I changed was adding the collar. A very small change that makes a very big difference in the way that it works. You have to understand that this is not my design. I am trying to build this to operate as closely as possible to the original American Hoist & Derrick design and that was one small detail that I did not get right. All I have to go by is a rusted hulk that sat submerged in salt water for about 50 years. There is also an original sales brochure that includes some drawings (engravings?) but these are not detailed technical drawings. There are two drawings that show the thrust collar. In one drawing, the artist got it right but in the other he got it wrong and his confusion added to my confusion. If I confused you with by description, well, there seems to be a lot of that going around.

Jerry


----------



## Captain Jerry (Feb 9, 2012)

Oops. That's not all I changed. I modified the screw thread that drives the thrust pin so that there is a knuckle-in or over center action. I'll try to post a quick drawing to explain. It will take a few minutes to get it posted and I will modify this post with an attachment.

The drawing/model has been added. This is the part that is attached to the handle and is rotated against a pin which sits in the slot. The reaction against the pin drives this part against the clutch actuation pin. The feature that was added is the flat spot shown in red. It gives a spot at the end of the rotation, when the clutch is fully engaged, for the reaction pin to rest on. It prevents the clutch from disengaging when the handle is released. On a long haul, the operator could set the clutch and then roll a cigarette (a two handed job for most) while the log was dragged to the landing.

Is that clear?                                                          21938

Jerry


----------



## Captain Jerry (Feb 13, 2012)

Jasonb  said:
			
		

> Fire door is probably best done by squashing a suitable piece of tube and flycutting the end with a boring head to the boiler OD plus the thickness of the flange. Bend the flange to fit the boiler and then silversolder onto the curved end of the tube. Finnaly cut off excess tube, file away the flange plate inside the tube and an equal amount all round the outside then rivit to boiler.



Jason

You posted the above reply on Brians thread but I wanted to reply here so as not to confuse the two projects. The fire door has been staring back at me for years and you made it sound so easy I had to give it a try today:











That was easy! Thanks for the tip. There is more to do but the biggest hurdle has been passed. I wish I had asked for help before.

Jerry


----------



## Brian Rupnow (Feb 13, 2012)

Looks good Jerry. ---Never be shy about asking for help on this forum. There are a lot of remarkably talented people who "see" things from a slightly different angle, making you wonder "Now damn---That was so simple!!! Why didn't I think of that???"


----------



## Captain Jerry (Feb 13, 2012)

Well, here is the progress that has been made in the last few days. I'm not going into very much detail because much of it has been show before.

The hoist bearing stands have been re-profiled to reduce their bulk and give better proportions. Just spent some time on the mill.






Then I looked at the cylinders. I either had a poor plan or no plan at all for mounting them on the deck frame. Reluctantly, I decided they need to be made over. I like the look of brass but I plan to paint this project and except for a few parts, I need to starting to see this in BLACK. So the new cylinders are made of aluminum with an integral mounting flange, just like the original AmHoist design.






Using methods that I developed for the cylinders on the vertical and horizontal over crank engines, It starts with two blocks of aluminum on the left, with some profiling on the lathe and the mill, to the finished cylinders on the right. Yes, that is an aluminum cylinder, with brass heads and brass clad with black showing through. I think I like the contrast even better that I did the previous all brass.

Now that I can mount the cylinders, I can turn my attention to the Cross head guides. AmHoist used a single flat bar under the cross head. The mounting and aligning of this bar gave me fits before but now it seems very straight forward. The bar that I am using is cast iron salvaged from a broken drill press vise. It is suspended from a brace on the frame under the back leg of the bearing stand and at the other end of the bar it is suspended from a bracket on the cylinder head.

Here's theirs:






Here's mine:











Work continues.                                                                 22281

Jerry


----------



## Jasonb (Feb 14, 2012)

See it wasn't that hard  You are making good progress and have a good scale loking model there.

J


----------



## Jared (Feb 16, 2012)

All right! Good to see this picking up again. I usually do things steady by jerks myself. Get burned out, do something else, half a year or two or five go by and I pick it up again. Looking forward to more.


----------



## Captain Jerry (Feb 16, 2012)

Jared

Thanks for watching.

I have been having difficulty staying focused and here is another example. A few days ago, I got distracted from my plans by a couple of post that showed me how to go about fabricating the fire door. I had not even been thinking about it until Brian mentioned it and Jason showed the way. I didn't quite finish it but I got it in good enough shape That I proved to myself that I could do it. 

This morning, my plan was to finish up the steam chest and covers so of course I took one look at this:






and said "that's not a fire door, that's a fire hole. Where is the door?" So forget the steam chest and covers and make a fire door. I still had about 1/2" of the squashed pipe that was used for the first part, so it was no big deal to make sure that I had a good flat end and then soldered it to a brass plate. Then sawed of the end with the plate plus 1/16" of the pipe. (Slitting saw in mill). Then a little cleaning, filing and finishing and here it is:











Now it's a fire door. Do you think it needs hinges?                                   22586

Jerry


----------



## Jasonb (Feb 17, 2012)

> Now it's a fire door. Do you think it needs hinges?



Oh Yes.

And a nice ring of rivits around the flange, then while you are at it a handle wouldn't look out of place 

J


----------



## metalmad (Feb 18, 2012)

Nice one Jerry :bow:
Pete


----------



## Captain Jerry (Feb 26, 2012)

It is really difficult getting organized to proceed with this. I keep getting distracted with non-important jobs, like the fire door. I finally realized that the reason for procrastination was that there were so many unsatisfactory parts that needed rebuilt that I was just avoiding them by fiddling around with other stuff. I needed a plan. Here it is. Since I am happy with the winch side of the project and mostly unhappy with the engine end of it, almost everything on the engine side of it will be remade. 

I had already remade the cylinders but I thought I would be able to salvage the heads and maybe the steam chests but that's just not going to happen. So it's most of it is being rebuilt. I have made some headway but have not been very careful with documentation because it is ground already covered.

I will try to cover some of the things done differently such as the bolt pattern for the cylinder heads. I'm using 2-56 fasteners with a six bolt pattern. I will be using socket head cap screws for convenience during initial assembly and adjusting but will switch to hex head bolts or studs with nut where appropriate. 

This is a first for me. No witness marks! Two cylinders, four heads, 24 drilled and tapped holes and they are all interchangeable! Any head fits either end of either cylinder and can be indexed to any position without worry. Every other cylinder that I have ever made was a nightmare of fitting, filing, marking and mahem. How did I do it? By eye.

I am being called for dinner and so I will post this now and continue with more after dinner.

Jerry


----------



## Brian Rupnow (Feb 26, 2012)

Jerry--- You and I seem to be approaching this from opposite ends. I am just in the final stages of engine building, and about to embark on the winch mechanisms. Its always interesting and informative to read your posts. ----Brian


----------



## Captain Jerry (Feb 26, 2012)

Back from dinner. Eyeball positioning works like this. You put your eyeball on your DRO and use it carefully. There is no other way. Careful layout, marking and center punching has failed as has the use of a rotab. Maybe poor technique contributed to the bad results but I have finally achieved the results using inexpensive Grizzly/Igaging DROs at a cost of less than $50 and a second hand Last Word DTI.

Even the best DRO is only as good as its starting point and to me, the only valid starting point is the center of the bore. It takes a little care to set the cylinder vertical in the vise, with the valve face against the fixed jaw. Then you need to get it centered under the spindle. I can get repeatable position accuracy with .001" using the conical point of a center/edge finder but only if the bore is less that 3/8". Using the cylindrical end and a lot of repeated sampling against the inside edge, the best I can do is about .002" I'm not all that confident about that. Using the DTI against the inner face of the bore using the setup shown here, I can easily find the center within .0005" with a great deal of confidence.







Then with the X,Y zeroed on center, the radius is cranked into the +X. I always use an even number for this to eliminate rounding error in a later step. In this case, the radius is .400". On the first cycle around the cylinder I am using a spotting drill. The second position is spotted at -.400". Four positions left. Crank in the +Y as R x cos(30°) = .3464 and if your cheap shop calculator doesn't have trig functions, cos(30°) = sqrt(.75) or just remember .8660. My DRO only only has three decimal display so I crank in Y = .346 and lock the Y. Then move the X to R/2 and since I am on the negative side of the scale the position is X = -.200 Spot #3. Then leaving the Y locked, move to X = +.200, Spot #4. Leaving the X locked move to Y=-.346, Spot #5. Then leaving Y locked, move to X=-200, Spot #6. Replace with the tap size drill and go around again and then replace with the tap and go around again. You only need simple calculations that you can probably do in your head. The radius, half of the radius, and the radius x .866 but don't do it in your head, use a calculator.

Drilling clearance holes in the heads follows the same positioning procedure except for the starting point.  If it is possible to sweep the entire circumference the use the DTI as above but otherwise you will have to use the edge finder method. Be sure to center the Y axis first! 

It took forever to write this and I had two glasses of wine with dinner, so If it's not clear, ask a question and I'll answer tomorrow.
                                                                      23340
Jerry


----------



## Captain Jerry (Feb 27, 2012)

Today I rebuilt the eccentric straps. I had previously made a one piece eccentric strap because I wasn't sure how to do this but when I built the overcrank engine, I made a two piece eccentric strap with a slant. Here is where it came from:






That is a cut from the American Hoist brochure and I have wondered why it was made on a slant like this but there is very little room between the bearing hoist bearing stands and the crank web, where the eccentric lives, and access to the bottom bolt is made much easier by making it like this. What is not clear from the picture is that the eccentrics, which are integral with the crank web on this engine, are slightly recessed in the web so the eccentric strap has an offset to get in there. Also shown in the picture is the flat bar on the end of the bent valve rod that slides in a guide on the bearing stand like a crosshead guide. It adds a little interest to the mix. 

My approach to split ecc straps is to lay it out, drill and tap for the bolts and then saw it in half (without the bolts). Then I put the bolts in and proceed with the shaping. Another nice benefit from the slant aspect is that I could get the parts out of a 1 inch wide bar and it would have to be a 1 1/4" bar if straight. Here are some pics of the process:




































They just need a little more cosmetic milling and filing before boring the center for the eccentric.

Jerry


----------



## zeeprogrammer (Feb 29, 2012)

It's been a while for me Jerry but I sure did enjoy going through your thread again. The gear cutting, clutch mechanism (excellent!), trials and tribulations. It's a great thread.

A belated 'aye' from me.


----------



## Captain Jerry (Mar 7, 2012)

Hi Zee, thanks for stopping by and leaving a message. The donkey and I are still growing. It may be as painful for the donkey as it is for me.

I am beginning to form a plan of attack on the brake band and it may work out with a little help. I was not sure how to form the strap without slip rolls but as it turns out hammer and anvil worked out just fine. Here are a few pics of the formed strap.
















One end of the strap is to be fixed to the frame and the other end will be attached to a link and a foot pedal. The inside of the strap will be covered by some friction material that will contact the outer surface of the clutch/brake drum. I don't think I will have any problem with the linkage but I don't know what to use for friction material and how to attach it to the strap. I think it will be glued to the inside of the strap, probably with contact cement but I don't know what kind of material to use.

Help Please! Your suggestions will be much appreciated.

Jerry


----------



## JorgensenSteam (Mar 7, 2012)

This entire build is great, but that connecting rod and bearings are spectacular.
You gotta love that beautiful taper.

And that cylinder lagging is pretty slick too.


----------



## arnoldb (Mar 8, 2012)

It's really coming along great Jerry Thm:

How about a strip of leather for the friction material ?

Kind regards, Arnold


----------



## tel (Mar 8, 2012)

> The inside of the strap will be covered by some friction material that will contact the outer surface of the clutch/brake drum. I don't think I will have any problem with the linkage but I don't know what to use for friction material and how to attach it to the strap. I think it will be glued to the inside of the strap, probably with contact cement but I don't know what kind of material to use.



There should be no need for lining material on the brakes - metal on metal should be just fine - again, _*think chainsaw!*_


----------



## Jasonb (Mar 8, 2012)

When I used to play around with IC off road models the centrifugal clutch bell was lined with a fibre type material which was about 1mm thick and quite flexible, just stuck a strip in with epoxy and it never shifted with all the heat and oil.

J


----------



## Brian Rupnow (Mar 8, 2012)

Jerry--give serious thought to a thin band of cast irom loctited to the outer diameter of the brass part that the brake band will rub against. That way the brake band can be made from a very large stainless steel pipe clamp. These are available without all the serrations for the tightening screw. A thin shell of cast iron can be liberated from a piece of cast iron pipe. Brass is simply too soft for any kind of brake and will gall.----Brian


----------



## Captain Jerry (Mar 8, 2012)

Leather sounds like a good possibility, Arnold. It is one of the first things that I thought of but I don't know where to find it in the right thickness and texture. It needs to be thinner than belt leather. My wife has a pair of black leather gloves that she hasn't worn in thirty years. They are too long to be stylish today and a small strip from the cuff would hardly be missed. What do you think of my chances of getting away with it?

Tel, if the drum were made of steel, I would go with metal to metal, but the drum is brass and so is the strap. It would work from a functional point of view but I would hate to mess up the drum surface. As I am writing this, I am thinking that it isn't a high cycle, high load application so maybe I'll go naked.

Jason. Some kind of fibre material like you describe is exactly the right idea. Where did you get it?

Brian. The idea of a cast iron tire on the drum is good. It would solve the galling problem and I could still use the brass strap. If I was building this for heavy duty, I'm sure that is what I would do. If I come across an appropriate piece of CI, I will experiment with it. 

Thanks for the input. All of the suggestions have merit. The hunt is still on. At least I can continue to develop the mechanism while I look for the material.

Jerry


----------



## Jasonb (Mar 8, 2012)

May be easier to fit the lining material to the outside of the brass drum and then use a steel strap, spring steel is good but flat stock works OK, this is the band for my Traction engine about 6" dia






You could always use a wooden lining for the brake, plenty of traction engiens with that arrangement

J


----------



## techonehundred (Mar 8, 2012)

If you don't want to try leather, Go to the local autoparts store and get some different gasket material. Some is asbestos and some cork. They should be fine for this application.


----------



## arnoldb (Mar 8, 2012)

: I forget about the big oceans in between... Locally here in Namibia they make shoes called "velskoene' and traditionally those have leather laces that are fairly thin strips of leather.

If you know of someone that restores old books, you might be able to get some thin leather from them. Some furniture and car seats also use thin leather, so a local upholsterer might be able to help you as well - just a couple of thoughts.

I don't think the texture will play that much of a role; but a suede-type might just have the edge.

I may be a bachelor, but I know enough about women and their fashions - the possibility that those gloves might come back into fashion at any moment in time might leave you in for the high jump ;D

Kind regards, Arnold


----------



## ShopShoe (Mar 8, 2012)

Sometimes you can get good leather from (discarded) handbags, purses, wallets, etc. I once used some of that to repair an diaphragm type air compressor.

Around here, some of the fabric shops have remainder bins where you can pick up pieces of different fabric and materials cheaply. I once "anti-rattle" lined the toolbox I kept in my car with upholstery vinyl for 25 cents US.

--ShopShoe


----------



## ronkh (Mar 8, 2012)

Jerry.

Please DO NOT cut up those leather gloves. *club*
I for one wish to see more builds from you in the future!! (And that means you being in one piece to be able to)!

I have found out to my cost, just the once, that it's better to NEVER to take a chance with womens things. :hDe: :fan:

Kind regards,

Ron.


----------



## Brian Rupnow (Mar 8, 2012)

Jerry---It doesn't have to be cast iron There is every size of thin-wall steel tubing known to man available out there. A peice loctited to the outside of your brake drum is the way to go.


----------



## tel (Mar 8, 2012)

> Tel, if the drum were made of steel, I would go with metal to metal, but the drum is brass and so is the strap. It would work from a functional point of view but I would hate to mess up the drum surface. As I am writing this, I am thinking that it isn't a high cycle, high load application so maybe I'll go naked.



I can't see it being a problem. It does depend a bit on the prototype tho, dunnit! Does/did the original engine have liners?


----------



## Captain Jerry (Mar 9, 2012)

OK. the gloves are off the table. My wife came in the bedroom and caught me feeling the fine texture of the leather and I guess I had a guilty look or something so she said "Aren't you a little old to be playing with Mommy's fine things?" I knew I would catch hell if I told her what I was really thinking so I just said "Opps! Busted" and slunk out of the room. This is a weird place that I live.

Tel

Here is a pic of the real animal. You can see some kind of material between the band and the drum surface. You can also see the bolt or rivet heads that secure the lining to the band. It looks to me, like ordinary asbestos brake lining. 











In the shop today, I tried the brass band against the brass drum. It doesn't take much pressure to stop the drum but it showed another reason that lining is needed. Noise. The very slight metal to metal contact when the brake is disengaged makes the band sing like a bell. Very annoying. A little sound damping would be a good thing.

There are a couple of other details worth mentioning. It has been suggested that the ratchet and pawls are not needed on this type of hoist but you can clearly see the wear on the teeth,more obvious on the front drum, indicating heavy use and abuse of this feature.

From this point of view, you can see the small pockets in the drum flange, close to the drum core and arrayed radially around the drum. These pockets are to mount the wooden lagging staves to increase the dr.um diameter and line speed on lightly loaded applications.

Thanks for watching.

Jerry


----------



## tel (Mar 9, 2012)

Yes, Harris included the ratchets/pawls on his model, along with a brief explanation of their use - well worth including.

Looks like brake linings are 'on' then - I have some of that rubberised cork stuff here that might serve?


----------



## metalmad (Mar 9, 2012)

Hi Jerry
what about Hardwood segments for the brake material ?
might not be doable who knows 
Pete


----------



## Captain Jerry (Mar 9, 2012)

techonehundred  said:
			
		

> If you don't want to try leather, Go to the local autoparts store and get some different gasket material. Some is asbestos and some cork. They should be fine for this application.



Well tomorrow I'm off to the autoparts store to checkout gasket materal as advised by Techonehundred, (Thanks)



			
				ShopShoe  said:
			
		

> Sometimes you can get good leather from (discarded) handbags, purses, wallets, etc. I once used some of that to repair an diaphragm type air compressor.
> 
> Around here, some of the fabric shops have remainder bins where you can pick up pieces of different fabric and materials cheaply. I once "anti-rattle" lined the toolbox I kept in my car with upholstery vinyl for 25 cents US.
> 
> --ShopShoe



and to the fabric shops, as advised by Shopshoe but I'm going to feel a little funny asking the lady at the counter if she has anything to repair a diaphram.

Arnold, suede would seem like a good choice. Maybe even psuedo suede or some kind of imitation.

Pete, I don't think I could get hardwood blocks to work out at this scale but maybe I could use wood veneer strips as used for edge banding. I'll check the home improvement stores.

I may not get much donkey work done for a few days. It seems that my manager has secured a non-paying contract for me to move some cabinets and install new countertops and sink for the grandmother of my son-in-law's son-in-law. Extended families offer a lot of opportunity for recreation.

Jerry


----------



## Jasonb (Mar 9, 2012)

Jerry what Dia is the brake drum, as I said earlier wood is often used on traction engines and the engine in my avitar has a 3" brake drum and a series of laminated wood blocks fitted to the band, it would also be easy to go smaller. I'll take a wheel off this evening and take a picture for you.

J


----------



## metalmad (Mar 9, 2012)

Hi Jason 
sorry mate that will teach me to only look at the photos :big:
Pete


----------



## Blogwitch (Mar 9, 2012)

Jerry,

Just get some cardboard off your cornflakes packet and five minute epoxy glue it into position inside the brake band. You will be very surprised how long it lasts.

In the 70's, I used to do a bit of model car racing, and that is what I eventually used in the band brake around the centrifugal clutch (which had a cork liner). Once it has glazed over, it lasts for ages.

Eventual replacement is easy as well, just eat more cornflakes. Or if you want it a little thicker, shoe boxes are about twice as thick.


John


----------



## JorgensenSteam (Mar 9, 2012)

They make self-adhesive hardwood veneer edging.
You could try oak or hickory if you can find it.


----------



## Jasonb (Mar 9, 2012)

Here you go, the blocks were made by laminating several layers of veneer around a former and then cutting into segments. The blocks are about 3/16" deep as there is an 1/8" recess in the drum rim. Retained onto the strap with expoxy and glued in rivits.







Black poplar is the usual choice on full size as it is difficult to burn but don't be tempted to use NA Poplar.


----------



## Captain Jerry (Mar 9, 2012)

John - My breakfast choice is Multi Grain Cherrios. I guess that might work just as well.

Arnold - Thanks for the picture. The brake drum is just under 2.5" dia. Hardwood blocks have always seemed to me to be the right stuff. Mostly because of the remote locations where they were used. I would think that they had better access to a wagon wheel maker than they would to an industrial supply house.  Gluing up veneer around a former solves the production problem. The donkey drum does not have a groove but I think there is enough thickness to cut a shallow groove. I'm not concerned with alignment but I want the outer diameter of the band to be at the same height as the pawls.

Thanks for watching.

Jerry


----------



## Brian Rupnow (Mar 9, 2012)

Jerry---As soon as I shut my computer off to go to bed, I remembered a question I wanted to ask you and had to turn it back on. Do you have any kind of spring to retract the clutch shoes so they don't drag when not actively engaged? I am working on the clutch for my Donkey right now, and it has occured to me that if I made the bore in the end of the shaft that supports the winch drum deeper, down past the cross pin, I could put a small diameter compression spring, similar to that in a ball point pen, only stronger down into a blind counterbore which would activly push the cross-pin out towards the end which has the activation lever on it, thus ensuring that the clutch shoes will never drag when not engaged.--You may have already devised a method of doing that, but if not, I thought I would share this with you.----Brian


----------



## Captain Jerry (Mar 9, 2012)

The kitchen job was postponed so I got some done today. Cutting ratchet teeth is like gear cutting except an endmill is used. Set up the RT. Center the drum. Adjust depth of cut. 20 teeth requires 20 hole plate, 3 full turns + 12 holes on my 72:1 4" RT.






The brake drum is 2.4" dia x PI = 7.4" circumference / .375" ( approx tooth space) = 20.1 or 20 whole teeth.










Change of subject.










Here is a part from the original machine. I'm not sure what part it is but I have two possibilities. It might be the bracket that held the diagonal boiler support stay to the side of the boiler or it might be a support bracket that held the steam valve control valve shaft. It has a part number cast into it, as do all parts of the machine. If anyone has a parts reference for this machine, I will post the part number and maybe you can help figure it out.

I liberated this part a few years ago when I still had a boat in this marina. The part was not attached to anything, just lying on the deck. I told the marina owner that I was building a model of the donkey and asked if I could have it. He generously agreed and he is not known for his generosity. 

I have two thoughts on it use. It could just be displayed with the model, as is, or I could try to use the material to produce a part for the model. The part is not pristine. There is a recent scar where someone used a hacksaw on it, not sure why? Before cutting it up for material, I would like to identify the part and if possible, make the same part from it.

Any thoughts or suggestions?

Jerry


----------



## Captain Jerry (Mar 9, 2012)

Brian

I have not incorporated a spring to retract the clutch. I had thought that I might do it the way that it was done on the original. AmHoist use small coil springs, radially between the shoe and the gear plate. You can see the spring in the upper left corner of this picture.






I had thought that the model train shops might have something suitable but I don't think it is necessary. Extensive testing (playing) with the clutch mechanism shows no tendency of the clutch to hang up and not disengage, even under heavy loading. The operation of the clutch is so smooth and reliable that I am reluctant to make any modifications. I have thought that a spring washer between the gear face and the cross bar could be used. I'm not sure that I used the right term for this spring but it looks like a bent washer made of spring steel or beryllium/copper.

Jerry


----------



## Nickademusss (Mar 13, 2012)

I am in Awe, thank for posting your progress so far, its fascinating to see the set ups you use for small parts and its looking amazing! 

Zac


----------



## Captain Jerry (Mar 20, 2012)

Whats under the hood? Here is a quote from the Amhoist brochure.







Here is a little exercise that I tried yesterday. It proved the method so now I will do it again with a bit more care. The top of the boiler is a mess of pipes and valves and the hood is just a tin roof to keep debris out so I thought I would try a little tin work. I wasn't sure what was going to happen so I only got pics of the results. I didn't do a thorough layout job but it doesn't take much. Just layout a circle with a radius equal to the hood width (on the slope). Cut it out with the snips and then make one cut from the edge to the center. It helps to have a punched or drilled hole at the center. Then just roll it into a cone with your fingers and when the slope looks right, tape it to hold and rivet the edge. 











That's about it. There will be a little more when I get to the piping.

You might notice that the donkey base is empty. Since restarting this project, it was clear that the previous base was inadequate for the installation of the mechanism to operate the brakes and pawls, and also poorly designed (in my model, not the original) to add the front drum, which is a bolt on assembly, so the base has been redesigned and rebuilt. I'll get some pics of that tomorrow

Jerry


----------



## Captain Jerry (Mar 23, 2012)

This is the current state of the hood.






The previous was just a test of the process and it worked ok so I started over with a little more care. The material is aluminum roof flashing available is several sizes at home improvement stores. I have always called this stuff roofing tin so in the interest of saved keystrokes I'll just call it "tin" from here on. It is easy to cut with heavy scissors but when formed into the funnel cone. The first step is to layout a circle with a radius equal to the distance from the edge of the boiler cylinder to the apex of the final cone.

Here I am using dividers to pick this dimension by eye.






Adding a little for overhang yields a dimension of 3.6" which I used to scribe a circle in the tin. I then scribed a radial line and stepped of 3/8" increments from the edge to the center for rivets. A second line, parallel to the radial line, is scribed for cutting.







The circle is cut with shears and then holes are drilled at the center and at each rivet location. For the rivets that I have the bit is 5/32". The surface is very smooth and the drill bit will wander so the locations must be punched but VERY lightly so the sheet is not distorted.






The tin is then cut along the line parallel to the rivet line. This line does not intersect the center hole so as the shears pass the last rivet hole, the cut takes a right turn and cuts int to center hole. IMPORTANT! The cut must not cross the center hole and nip the far side of the hole. If the for side of the hole is cut, you will have a very difficult time forming a regular cone without distortion.

Using your fingers, offset the cut edges and slide the tin into a cone shape, being careful not to kink or fold the tin. Continue to slide the tin tighter, until the cone is to the desired shape. Trust your eye, but the base of the cone should be just a bit larger than the boiler cylinder. I am quite capable of working out the math and geometry to cut a pie shaped wedge out of the circle that would yield a cone but the overlap method yields a smoother, stronger curve. With the cone formed to the right shape, using a sharp scriber, mark through the outer rivet hole to locate the mating hole.

I guess I lost my concentration here and forgot a process picture of this next step. Now lay the circle out flat and locate the marked location. Scribe a radial line through this point to the center, and step off 3/8" increments for rivet holes. Punch lightly and drill the holes.

Now the cone can be reformed and secured with a #2-56 bolt and nut. Do not rivet yet! There are more holes to mark and drill but first, note that the inner layer of tin hangs out slightly past the outer layer as shown here in red.






Mark this overhang with a sharp scriber, uncoil the cone and trim the excess before reforming the cone. Now we're ready to mark and drill the second row of rivets 180° from the first row. Mark the location with a magic marker as shown here.






Only one line is shown in the pic but I decided that four rows of rivets would look better so I made marks at 90° and 270° as well. Now unroll the cone and use the marks to scribe lines and step off the rivet hole locations, punch and drill.

These are only the exterior layer, so once again, form the cone, secure it with the bolt and use the outer ring of drilled holes to mark the locations on the inner layer. Be sure that the inner layer of tin is tightly pressed to the outer layer when marking.
I know this is getting very repetitive but again unroll the cone, pick up the marked locations, step off the rivet locations and drill.

WAIT! BUT FIRST! Before uncoiling the con in the above step. it is time to mark the location of the stack pipe which must be cut. I am using a piece of 1/2" brass pipe (ext diameter .875") for the stack pipe so I set the pipe down on the cone and scribed around it. When the cone is unrolled for the last time, this line is cleaned up and cut very carefully, using my wife's finest scissors (you know better).

Now the cone can be formed for the last time and riveted. Where did I get the rivets? At the junk yard (salvage yard)! No kidding! They have bins full of the little buggers. They are plated steel but they will be painted so why not. If I had the right sized copper rivets I would use them but I don't

Just a few more steps to finish. The cone is fairly stable but just needs a stiffener ring around the base for ridgidity and appearance. 12 guage copper wire is just the ticket, strong enough and easy to form. To get it into a smooth regular shape, I resort to one of my favorite tools, hammer and anvil.






Well rubber hammer and round anvil. The rubber hammer eases the wire into a smooth circle without marking the surface. It doesn't have to be beat to final size, just to near size. Final size is to fit the base of the cone with enough extra to bend up some ears for soldering.






Soft solder is fine for this. After soldering, it is closely trimmed and filed. Here it is on the cone. It has been fileted with J-B Weld and small nails are used to keep it forced to the edge of the cone, holding the circle and cone on a piece of scrap of HDPE (Starboard).






Here it is with a coat of primer. Another copper ring is in place to blend the transition to the stack pipe.






And one last pick with paint. way to glossy I think. If anyone has a good experience with a not too glossy black paint, I would appreciate a suggestion.






This has been a very long post. Almost longer that the build.                                

Thanks for watching.
                                                                      25920         
Jerry


----------



## Maryak (Mar 23, 2012)

Very Nice Hood :bow:

(Robin would be proud to wear it)

Best Regards
Bob


----------



## Blogwitch (Mar 23, 2012)

Nice bit of tinwork Jerry.

I used to hate doing plate development layout in my earlier years (a little bigger than that though, full sized stuff), I think maybe because I never seemed to get it quite right, and always ended up slightly the wrong shape or angle first time around. Tin snips and a hammer soon put it right though.

Just a thought, if you were to make another one, or someone doesn't quite have your abilities, a plastic funnel from the supermarket would maybe work just as well, seeing that it is non functional and also painted afterwards. What the eye doesn't see..........


John


----------



## Brian Rupnow (Mar 23, 2012)

Bogstandard  said:
			
		

> Nice bit of tinwork Jerry.
> 
> I used to hate doing plate development layout in my earlier years (a little bigger than that though, full sized stuff), I think maybe because I never seemed to get it quite right, and always ended up slightly the wrong shape or angle first time around. Tin snips and a hammer soon put it right though.
> 
> John



My experience with developing cones from sheet metal parallels Johns!!! yours however looks very good, Jerry!!


----------



## Brian Rupnow (Mar 23, 2012)

Captain---In regards to non glossy black paint.---A trip to your automotive store should yield cans of "chassis black" in aerosol cans. This is a black that is not absolutely flat, but doesn't have a high shine to the finish.


----------



## Captain Jerry (Mar 23, 2012)

Maryak  said:
			
		

> Very Nice Hood :bow:
> 
> (Robin would be proud to wear it)
> 
> ...



I hadn't thought of it as a fashion statement but it might work down under.
http://upload.wikimedia.org/wikiped...-Hamlin.jpeg/399px-Tin-Man-poster-Hamlin.jpeg



			
				Bogstandard  said:
			
		

> Nice bit of tinwork Jerry.
> 
> I used to hate doing plate development layout in my earlier years (a little bigger than that though, full sized stuff), I think maybe because I never seemed to get it quite right, and always ended up slightly the wrong shape or angle first time around. Tin snips and a hammer soon put it right though.
> 
> ...



My first thought was a store bought funnel. I used to have a nice drawn aluminum funnel that I used to change oil on my generator but it may have been among the last metal funnels made. I searched the usual sources, including second hand stores, but came up short.  Plastic? OK for changing oil but my donkey deserves better.

I spent the summer, half a century ago, as a helper in a sheet metal shop, when ductwork was made of galvanized steel. I was also an engineering student at college, so the layout of transition pieces that joined rectangular duct to round was very interesting to me. Otherwise, this was one of the worst jobs I ever had. Wrapping ductwork with fiberglass insulation in an attic where the temp was over 100°F is something you don't forget.



			
				Brian Rupnow  said:
			
		

> Captain---In regards to non glossy black paint.---A trip to your automotive store should yield cans of "chassis black" in aerosol cans. This is a black that is not absolutely flat, but doesn't have a high shine to the finish.



Thanks for the tip, Brian. I'll check out "chassis black"

An thanks for watching.

Jerry


----------



## ronkh (Mar 27, 2012)

Well?


----------



## Captain Jerry (Apr 9, 2012)

A small update. The donkey is proceeding but slowly. One of the problems of reviving a project after a long period is that many of the parts made previously don't look as good to me as they did at the time that I made them so a lot of the parts are being remade. This gives me an opportunity to relearn some of the lessons that I learned in making those old parts.

I don't know if everyone agrees but there has been a lot of very fine work displayed on this forum lately. The level of detail, artistry and finish of several of them has made me re-evaluate my focus. I don't want to reverse this trend but I will show a few pictures of the state of the project.












As you can see, I have decided to return to the original two drum plan. Every time I open the parts box for this engine, that second gear and clutch drum look up at me. I just cant ignore them. The front frames need to be profiled but I wanted to verify gear mesh first.

Along the way, some other detail captures my attention, and I take a little side track, like these ash clean out doors.











Thanks for watching.

Jerry


----------



## Brian Rupnow (Apr 9, 2012)

Very cool detail Jerry. Thats what I was planning on doing next to my own donkey, if those elbows from PM Research don't appear here soon.---Brian


----------



## Captain Jerry (Apr 11, 2012)

Here is today's effort. The right front frame has been profiled to shape and attached to the main frame.






There is a little more fine tuning to the shape but it is close. The boss surrounding the shaft bearing is 1" diameter and will be reduced to about 7/8" after the clutch actuator assembly is mounted and the bearing cap will be profiled to match the rear hoist bearing cap. I didn't get to left hand frame. that will be for tomorrow.

I also decided it was time for a partial assembly to check clearances and alignment. The main things that I needed to check was clearances, alignment and gear mesh. 






All went well except that both eccentric straps needed a stoke or two of the file to reduce the thickness and eliminate some binding. The gear mesh of the front drum to the pinion was what I was most worried about and a little file adjustment to the mating surfaces on the front of the main frame and the rear of the front frame. It is now perfect. (I'll be the judge of that)

Another big reason for the assembly is to help visualize the location of all of the mechanism inside the frame. There are two brake linkages, operated by foot pedals, and two ratchet linkages, operated by hand levers. The ratchet pawls are lifted into the ratchet teeth through a coil spring so that it can over ride in one direction and lock in the other direction.

I don't have any plans for this and the machine that I am using for reference has lost almost all of this through age and rust. It is also very difficult to get under the thing to do any measuring.

Thanks for watching.                                                       27329

Jerry


----------



## Ken I (Apr 13, 2012)

O Captain! my Captain !
                What a wonderous piece of work - I don't know why I haven't read this thread before - my appologies for not chipping in sooner - the thread predates my signing on.

So I've spent an hour plus going through this and Brian's Donkey engine thread.

I see someone asked (but was never answered) why a "donkey" engine - I presume because it was used to repace mules in haulage applictions - or am I off beam here ?

Definitely interested in plans - should you care to post them in the downloads section.

Regards,
      Ken


----------



## Captain Jerry (Apr 13, 2012)

Ken

This project is so old that it predates a lot of things. I'm glad you dropped in. There has been some discussion of the term "donkey" and I am mystified why it isn't called a "steam horse" or a "steam mule" which are the animals that it replaced in the logging industry where they were used. Maybe its because, like a donkey, it can refuse to work for no apparent reason, or maybe the donkey had a better public image in the late 1800's when they first appeared.

They got their start in logging but were also widely used in mining, heavy construction, industry, and marine applications. They did so much more than just drag logs out of the woods, and there are lots of things that can be put on the end of the cable besides a hook. When I picture this machine at work, I see it mounted on a barge with an "A" frame boom and either a clamshell bucket or a piledriver but that's just my point of view.

Thanks for watching.
                                                                          27621
Jerry


----------



## Brian Rupnow (Apr 13, 2012)

Jerry---Have you had the engines running yet?


----------



## Captain Jerry (Apr 13, 2012)

Not yet Brian. Funny you should ask as I was just thinking about that today. One reason I was thinking about that part of the came for the recent trial assembly. I have recently changed from a 3" aluminum pipe to a 3 1/2" aluminum pipe for the faux boiler. To be true to scale, it should be 3 1/4" but you use what you can find. The bigger pipe looks better but when it is positioned on the deck there is no room to remove the steam chest covers. I think you mentioned this problem. I had not thought too much about this until I realized how difficult it was going to be to move the boiler after the piping is fitted. I plan to shave about .050" off of the valve face on the cylinder and about .020" off each side of the steam chest so that will increase the clearance by .090" on each side. That is still not enough space to work but it will look better.

The biggest problem that I have to deal with is the way that American Hoist designed the valve rod and the guide. The rod is a single piece, from the valve to the guide which is on the hoist frame and it has a large bend. When the rod is disconnected from the eccentric rod, there is no room to rotate the valve rod a full turn to adjust the valve, because of the bend.

The usual method of using a small bar with a tapped hole captured in a channel on the valve is going to have to be changed. I need to be able to adjust the valve nut instead of rotating the valve rod, and I need to be able to do it without removing the steam chest cover.

I have a plan but I won't get to it until next week.

You have said 'engines' before but since there is only one crankshaft, I think of it as one engine with two cylinders.

Jerry


----------



## Brian Rupnow (Apr 13, 2012)

Don't get too hung up on an exact, authentic scaled down model. There isn't anybody left alive today who really remembers exactly how these things looked/went together. The world of model building is a lot like the world of hot rodding----If it looks right, then it probably is right!!!


----------



## Maryak (Apr 13, 2012)

Captain Jerry  said:
			
		

> This project is so old that it predates a lot of things. I'm glad you dropped in. There has been some discussion of the term "donkey" and I am mystified why it isn't called a "steam horse" or a "steam mule" which are the animals that it replaced in the logging industry where they were used. Maybe its because, like a donkey, it can refuse to work for no apparent reason, or maybe the donkey had a better public image in the late 1800's when they first appeared.



A donkey could be described as an auxiliary horse

donkey boiler - auxiliary boiler

donkey engine - auxiliary engine

donkey man one who looks after and or operates the auxiliaries.

Best Regards
Bob


----------



## Captain Jerry (Apr 18, 2012)

Last week, I said that I had to come up with a different way to adjust the valves on this engine. That's because the one piece valve rod with a bend can't be disconnected and rotated to change the length. Here is what that looks like.






 Even if there was room to make a full revolution of the rod, the 56 TPI thread would move the valve about .018" which might be a little coarse for best performance so instead of rotating the valve rod, I decided to rotate the valve nut. The usual valve nut is a tapped bar that lies in a slot in the valve and can only be rotated in increments of 180&#176; and then only by loosening and lifting the valve chest clear of the valve face. So I decided to replace the valve nut with a spool that can be infinitely adjusted. It is accessed by a screwdriver through a port in the back end of the valve chest. The port will be sealed by a screw in plug after adjustment is made. The initial adjustment will be made by eye with the cover off and the fine tuning carried out with the cover on after test runs.

Here is a video of the valve being adjusted.





To keep the spool from rotating under use, the spool/rod thread is made TIGHT! I can't do much about the tap but when threading the valve rod, I used and adjustable die that was opened to produce a slightly oversize thread. That, plus the length of the spool should be enough to keep it in place. The adjustment takes some effort to turn.

I don't think that this is an original idea. I can't remember if or where I have seen it used, so if it was your idea, "Thank you, whoever you are," but if it turns out to be original, "You're welcome."

Thanks for watching.
                                                                     28162
Jerry


----------



## Blogwitch (Apr 19, 2012)

A wonderous creation you are making there Jerry.

When it is finished, people will be able to admire it for what it is, a good representation of an engine long gone, and I am sure no-one will pick you up for using a tiny bit of artistic licence in recreating missing or unseen parts.


John


----------



## krv3000 (Apr 19, 2012)

HI Jerry. fantastic


----------



## moconnor (Apr 19, 2012)

Hello Jerry,

Fascinating project. So glad that you are working on it again.

Is the access port in the valve chest for the screwdriver slot on the opposite end as the valve rod? I was wondering if you couldn't drill and tap that end for a socket head set screw to lock your spool in place after the adjustment. It looks like there may still be enough of a screwdriver slot left at the outside to adjust the spool after a set screw in installed. You have probably already considered this, but thought I'd mention it just in case.

Thanks for sharing your project. It is very interesting watching the design and problem solving as you progress. Great job documenting it too.

Kind regards,
Mike


----------



## Captain Jerry (Apr 20, 2012)

John, KRV3000, and Mike

Thanks for posting your comments. I have taken so long to get to this point in the project and am making such slow progress that I fear most of the viewers have been put to sleep. This may be the project of a lifetime but only because of the slow pace.

I did think about using a locking screw in the spool as you suggest, Mike. The spool is tapped for the full length so it could be done easily and there is plenty of room for it. But I really think it is unnecessary. The spool is a very tight fit and if I don't wear out the thread with to much fiddling, I think it will hold. This is just the first attempt and will be refined. You can see the cross slot that previously held the regular nut. 

Thanks for watching.

Jerry


----------



## arnoldb (Apr 20, 2012)

Captain Jerry  said:
			
		

> I have taken so long to get to this point in the project and am making such slow progress that I fear most of the viewers have been put to sleep. This may be the project of a lifetime but only because of the slow pace.


Not at all Jerry ;D - just following along without additional comments to add except for that you're doing a great job :bow:
Build it at your own pace - it's not a race; just a pleasurable pastime Thm:

Kind regards, Arnold


----------



## miner49r (Apr 20, 2012)

Jerry,
This build finally caught my attention. Very impressive work.
Alan


----------



## ronkh (Apr 20, 2012)

Jerry,

I am still watching with much growing greatest interest and I for one have not, and COULD NOT, fall asleep with this!
Don't you dare stop showing your posts/build.

Kind regards,

Ron.


----------



## tel (Apr 20, 2012)

I'm still here as well - I really want to do one of these, but not until I've got a few other half done things out of the way


----------



## Jared (Apr 21, 2012)

I'm here!


----------



## bearcar1 (Apr 21, 2012)

Nicely done Jerry! I especially appreciate your attention to the finer details. The models I find most attractive are the ones that are in fact built, not as stand-off scale, but ones that possess at the very least, true representations of the part or parts involved. On such a project as this one, the more detail you can put into it the better and boy have you done a terrific job so far. :bow: Of course all of these finer things takes a lot more time obviously, both in the thought process as well as the making of the pieces themselves. The final result .... a masterpiece such a this one. Tally Ho!

BC1
Jim


----------



## rebush (Apr 27, 2012)

Jerry: Have enjoyed watching your progress. What a great build. Between the pictures and your narrative I feel like I'm a part of your project. Thank for taking the time to share your knowledge. Roger


----------



## Captain Jerry (Apr 30, 2012)

I haven't posted much on this for quite a while but I have been working on it. The problem is that the progress has been difficult. Lots of effort, little success. Not spectacular failures that you might enjoy. Just disappointing results. The problem is scale.  At a scale of 12:1 there are some things that can't be done without the skills of a watchmaker but still need to be represented in some way.

In their brochure, they specifically mention that steam and exhaust piping to the steam chest uses bolted flanges so that is what I have been wrestling with. Both steam inlet and exhaust flanges are on top of the cylinder and the exhaust piping leads up into the funnel where it aids draft and takes the steam away from the operator. The steam piping passes through a control valve and then branches to the two cylinders in an unusual 3 way elbow. Here is a cut from the brochure:







From the day I started this project, I have dreaded the day that I had to deal with this elbow and the valve. The valve has a very long stem (about 4' that has two handles that are convenient to the operators location. The branching 3 way elbow below the valve is unique. No such thing from PM Research and not easily found in full size either. And at 12:1 scale, these things are very small. My usual approach to things like this is to ignore them until a solution pops out of thin air.

Today, under pressure, a solution appeared. I decided to make the valve and the three way elbow as a single piece. This is a departure from the original design but it keeps the flavor of the original (SORT OF).  I have convinced myself that if I had been there as a consultant on the original design, it might have been done this way.






The bottom end of the control valve is ball shaped and the lines to the individual cylinders branch from there. I have decided to bend the steam pipes instead of using elbows. The flow should be better. All piping connections at the cylinder use flanges and ferules as per AmHoist specs.

Much more to work out In this piping. I don't want to use anything smaller than #2-56tpi and SHCS will be used until all other assembly details have been worked out, just for convenience. If I ever get to a point of completion, one of the final steps will be changing to studs and nuts.

Thanks for watching.

Jerry


----------



## kustomkb (Apr 30, 2012)

It looks really good Jerry.

I am sure the original designers would be proud. You should be too.

Keep at 'er!


----------



## miner49r (May 1, 2012)

The flanges and pipe bends really clean up the look. They were probably easier too.
Alan


----------



## Jasonb (May 1, 2012)

Surprised you went through all the worry about the look of flanges and then just opted for bent pipes, to me the cast pipe fittings are more a feature of American steam than flanges. Its also quite easy to solder a socket to the side of an elbow to make the 3-way.

Just for an idea of scale what size pipes are you using for supply and exhaust?

Hard to tell from the old illustration but did the end of the valve have a support from the boiler stay, this would have saved excess strain on teh valve and spindle.

J


----------



## Captain Jerry (May 1, 2012)

Thank you Kevin and Miner49er for the kind comments, and thanks for leaving a note that shows you are watching.

Thanks Jason for the critical comment. This forum needs a little more of that. It is easy to say "nice job" and much harder to say "think again". So I thought about it. My solution wasn't all that great. My next one may not be either.

I got into this situation by lack of experience and lack of forethought and choice of a scale (1:12) that makes some of the finer points of the model very difficult to reproduce. I started with the larger parts of the project when I should have given more thought to the smallest. If I had chosen a larger scale, I wouldn't have this problem.

Pipe size:






This is the steam pipe on the port side. I measure it at 2" OD which at 1/12 scale equals 1.67" so I will use 5/32" tube for air in and 3/16" for exhaust. I might have been better of to choose 3/16" inlet and 1/4" exhaust. Then I could use the PM research cast elbows, but for some reason they just look too big to me.

Can I do any better? Probably not but I tried. Here is the results of a lot of filing on a three way elbow. Does this look better?






Here is another cut from the brochure. It seems to show that there is a bracket of some kind that supports the shaft of the steam control on the boiler stay. I circled it in red for emphasis. The other item that is circled in red on the steam pipe above the control valve is a mystery to me. What is it?






While taking a look at the brochure, it is clear that "truth in advertising" was not all that important at the time. Do the gentle bends of the exhaust pipe really add 17% to the power? At the top of those pipes with the gentle bends is a 90&#176; elbow. Does that help or hurt?

The next paragraph shows how important AMHOISt thought the flanges were. I couldn't think of any other way to make it work. The piping can be assembled and then bolted to the cylinders.






I am still undecided on this.

Jerry


----------



## gbritnell (May 1, 2012)

Hi Jerry,
I would say that the device you have circled is a lubricator. 
gbritnell


----------



## Jasonb (May 2, 2012)

3-way looks a lot better. Agree it may not seem nice to say it sometimes but there are a lot that just like to say nice job but a bit of constructive critisisum should not go amis now and then.

I also think that it is a displacement lubricator, condensate would form in it, sink to the botton and displace the oil which overflowed (being lighter than water) and was drawn into the steam pipe.

That bracket on the valve rod looks like it joined onto the diagonal boiler stay that is shown of the drawing you posted yesterday just behind the clutch handle so looks like you will have to add the stays.

The other way to avoid having to unscrew the pipework is to use unions which I mentioned in Brians build.


----------



## miner49r (May 2, 2012)

Jerry,
My read on the exhaust paragraph says two things...
a) The gentle bends reduce back pressure... I would agree but it is a minimal reduction
b) The separate exhaust pipes increase power by 17%... That's dual pipes as opposed to teeing both cylinders into on pipe. An engine is an air pump. The more you can do to help it breath the more efficient it is.
Alan


----------



## Captain Jerry (May 3, 2012)

I ordered some elbows. We'll see what it looks like.

Today's effort was the control valve. A simple project except for the size. The valve body is a 3/8" brass cube with spigots for pipe connection top and bottom. The valve spool is 1/4" polished shaft steel with a 1/8" through hole and a 5/32" sticky out part for the control shaft. The sticky out part is drilled 1/8" for the shaft with a 1/16" cross drilled hole for a pin. A 1/16" thick cover is held on with 4 #0-80 SHCS and nuts. It is simple and seems to be air tight and smooth operating, on/off in a 90° turn. There is room for some packing if it is needed.






The shaft is a piece of 1/8" stainless and the control handle is a piece of 1/8" CRS with a turned handle. The rest of the the shaft was then hammered to a square cross section and tapered before being finished with files and bent to shape.






Now I have to decide on the correct relation of this handle to the valve. Usually a handle is lined up with the valve, but I am not sure that is how I would want it if I was the operator. Straight down would be full on and off would be sticking out horizontally at the 9 o'clock position. I think, that if I were the operator, I would want to pull down to throttle up, so I would put the handle up between 10 o'clock and 11'oclock for full off, like this:






and pull down to between 7 o'clock and 8 o'clock for full speed, like this:






 The control shaft is at about the operator's shoulder height. This is adjustable with a grub screw on the prototype but I am going to have to cross pin the handle to make it secure so I have to decide. If there are thoughts or opinions or personal knowledge, please post it. I am really undecided on this.

Thanks for watching.

Jerry


----------



## Blogwitch (May 4, 2012)

Jerry,

For operating handles on machinery, they usually revert to off under adverse conditions.

So in fact, if gravity took over, or someone was to fall whilst still holding the handle, then going down would be the safe way to to turn the pressure off. 

To turn something on should always be more difficult than turning it off, hence larger red buttons on control boxes etc. So in your case, using safety logic, going up would be used to turn pressure on.

But on the other hand, it all depends who made the original engine, he might not have had safety in mind, just ease of operation, in which case, your method would be correct.


John


----------



## Jasonb (May 4, 2012)

I'm inclined to agree with John that the handles would ideally have a dead man action if they were down for off, looking at the illustrations you posted on the previous page that also seems to show them vertically down. Worth looking on the net for some old photos of donkeys in steam to see if any info can be gotten.

Nice bit of forging on the handle.

J


----------



## Maryak (May 4, 2012)

Bogstandard  said:
			
		

> So in fact, if gravity took over, or someone was to fall whilst still holding the handle, then going down would be the safe way to to turn the pressure off.
> 
> To turn something on should always be more difficult than turning it off, hence larger red buttons on control boxes etc. So in your case, using safety logic, going up would be used to turn pressure on.
> 
> John



Spot on Bogs with one notable important exception........"Boiler Gauge Glass Cocks for the steam and water connections." They are designed open in the down position so that they can't vibrate shut. The drain valve is down for shut, again so it can't vibrate open.

Best Regards
Bob


----------



## ProdEng (May 4, 2012)

Thanks for the details on making the handle, nice to see how it is done.

Jan


----------



## Blogwitch (May 4, 2012)

Jerry,

I hope that these couple of pics show you what you need to know.

By the looks of them, they are in a stopped position.












John


----------



## Captain Jerry (May 4, 2012)

John, Jason, Bob,

Thanks for the input. The consensus is clearly down for off. It is hard to disagree from a safety standpoint in today's environment. It is also hard to imagine a machine like this, with all of the open, unguarded mechanism and pinch points being allowed anywhere in today's environment. I guess I will go with that because that is what people would expect to see.

Thanks for the pictures, John. I really enjoy these and the skill of the illustrators of the time is amazing. They reveal a lot of interesting information. It is too bad that there is no detailed design information to go along with them. The differences in the two pictures is worth noting. In the top illustration, it appears that the normal operator's position is toward the rear of the machine. The brake pedal is just in front of the cylinder head, the throttle lever is moved back and the clutch lever pulls to the rear.

On the second illustration, the brake pedal is at the front, as is the throttle lever and the clutch lever pulls forward. They are clearly used in different applications.  It would be great to know why the difference.

Jan and Jason -- Thanks for noticing the forged handles. Hammer and anvil work is a nice diversion from the usual stuff. You will notice that I only show one throttle handle even though there will be two on the model. Getting the second one to match the first one will be a challenge. I will probably end up making several and choosing the best match.

Thanks for the input.

Jerry


----------



## Captain Jerry (May 7, 2012)

Here it is with cast fitting from PMR. Yeah, I think it is better. Thanks, Jason, for the tip on making the 3-way elbow.
















It will look much better than bent pipe at the top of the fake boiler, where there is a concentration of fittings.

Jerry


----------

