# Two New Engines



## Captain Jerry (Sep 25, 2011)

I'm starting a new project. I'm either going to build this engine:







Or I'm going to build this engine:







Here are a animations of the two engines:

http://screencast.com/t/lBLrfnGypa

http://screencast.com/t/iegJUGdOk


The two engines are not very different so if I can keep my head straight I will try to build both engines at the same time.
I have enough of the design work done to start making chips. None of the chips will be yellow, no brass, no bronze.

Jerry


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## steamer (Sep 25, 2011)

I like them both Captn.

Did you model that in Alibre? and then create the animation?

Nicely done!

Dave


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## Captain Jerry (Sep 26, 2011)

Dave

I modeled and animated both engines in Alibre' but the version that I have does not include the "motion" option so I have developed a work around method of creating animations that gives good results but it does not have anyway to export the motion. The only way I have to show the animation is to use a screen capture. I use JING and SCREENCAST (both free) to capture and share the output.

These engines are inspired by the "overcrank' or back-acting mechanism as built and shown by Stew Hart and Brian Rupnow. Researching the mechanism on the web and with the help provided here by other members I find that the back-acting type was used in marine engines which were usually compound engines. 

They are derived from the table engines and steeple engines of Henry Maudslay. My engines bear little resemblance to any of the predecessors except for the back-acting connecting rod. All of the examples that I could find except for Stew's wall engine used round rods instead of the flat plates so I have used round rods.

Taking a big clue from Elmer Verberg, the two engines share almost all of the mechanical part and only the structure or framework is different. The parts are bigger than Elmer's engines because I really dislike tapping #2-56 holes. Most fasteners will be #4-40 and the cylinders will be 5/8" bore and 1 1/4" stroke. 

I'm itching to get started but Monday's are mostly devoted to the entertainment of Marley, my two year old GREAT granddaughter. I'm re-learning the enjoyment of peanut butter, Cherrios, and Sponge Bob Squarepants.

Jerry


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## Ken I (Sep 26, 2011)

Both great looking designs - I'll be following this thread.

Great-grandfather - how are you so computer literate - I'm only up to grandkids and I'm stuck in a time warp of DOS based Acad10 - which I still use professionally - I'm a dinosaur.

Ken


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## tel (Sep 26, 2011)

My vote goes to the table engine!


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## lazylathe (Sep 26, 2011)

The same engines basically, one horizontal and one vertical.

I vote for the table engine, No 2!
Especially if you make the valve slide cover clear!!

Nice designs and animations!!!

Andrew


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## Brian Rupnow (Sep 26, 2011)

Nice work Jerry. I will be folowing along, best of luck.---Brian


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## Harold Lee (Sep 26, 2011)

Captain Jerry,

That is a very intriguing design. One thing is not clear from watching the animations or looking at the model is the detail on the back crank mechanism. I assume it also functions as a crosshead to transmit the linear force from the piston to the side force for the connecting rod and crank. It is not clear how it is located. do the four rods slide on the inside crank journals? 


Like Ken I am still at two year old granddaughters (two of em) and have found they much prefer Shaun The Sheep over Spongebob...

Keep us posted of your build.

Harold


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## Brian Rupnow (Sep 26, 2011)

Harold Lee  said:
			
		

> Captain Jerry,
> 
> That is a very intriguing design. One thing is not clear from watching the animations or looking at the model is the detail on the back crank mechanism. I assume it also functions as a crosshead to transmit the linear force from the piston to the side force for the connecting rod and crank. It is not clear how it is located. do the four rods slide on the inside crank journals?
> 
> ...




Harold---It shows up best in the first animation. There is a "spool" mounted inboard of the bearing supports that guides the cross head rods.


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## Captain Jerry (Sep 26, 2011)

Brian

Thanks for the terminology. Hereinafter it will be called a "spool" although I doubt that it will be freewheeling. I don't think I can let it roll and still have it provide the control needed without a ball bearing. The spool will be cast iron and the contact will be a sliding contact. If wear gets to be a problem, it can be loosened and rotated to present a new contact point. This is an untried method and may be subject to change if it doesn't work out.

Harold

You have zeroed in on an obvious design problem. As I said "most of the design work is done" but there are some details yet to work out. The slide assembly relies on the box structure of the four rods and the two end blocks for rigidity. I'm not sure that I can maintain that rigidity on the outboard end block and still have the con rod rotate on it. The con rod will have a typical marine style split end and bushings.

Things sometimes change between the computer and the shop which is 1/4 mile away.

Ken

I have two great grand daughters the same age but I get more time with Marley. It is an important part of my continuing education and sometimes the discoveries are as profound as they are entertaining. For example "If it doesn't have a tail, its not a monkey". [ame]http://www.youtube.com/watch?v=--szrOHtR6U[/ame]

My computer skills are self taught but I did spend some time developing computer software and formed my own company that distributed it nationally. I was old at the time.

Jerry


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## Harold Lee (Sep 26, 2011)

Captain Jerry  said:
			
		

> ... snip ...
> Harold
> 
> You have zeroed in on an obvious design problem. As I said "most of the design work is done" but there are some details yet to work out. The slide assembly relies on the box structure of the four rods and the two end blocks for rigidity. I'm not sure that I can maintain that rigidity on the outboard end block and still have the con rod rotate on it. The con rod will have a typical marine style split end and bushings.
> ...



In looking a Brian's avitar, which I am assuming you were referring to in your opening statement, it looks like his back crank mechanism is supported by two slide blocks. It will be interesting to see if you get the rigidity out of your design that you hope for. I will be following your build very closely. Thanks for sharing it with us.

Harold


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## Brian Rupnow (Sep 26, 2011)

Jerry---One point.--Using a "spool" as you have shown, you will only get "point contact" with the slide mechanism. If you change that round spool to a rectangular shape, then you will get greater contact area, thus greater guidance.


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## Captain Jerry (Sep 26, 2011)

Brian

My first thought was a square guide internally located, then two square guides externally located which would allow for adjustment. If this were to be a large scale design, I might go for external rollers. I like the appearance of the spool but it can be changed if needed.

Jerry


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## Brian Rupnow (Sep 26, 2011)

Jerry---The spool will probably work, and its a heck of a lot easier to put that radius matching the part being guided on a round turned part. The spool will have to be fixed---it cant contact both upper and lower guides AND roll. I don't think you need much more than point contact anyways, because those guides are ultimately rigidly fixed to the piston rod.


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## tel (Sep 26, 2011)

Can't see it being much of a problem really - the crosshead only has to keep the outer end of the piston rod travelling in a straight line.

Here I've got around a similar problem with just rods sliding in plain holes.


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## Captain Jerry (Sep 26, 2011)

I dont think the guide spool will be a problem but that is way down the road and there are a lot of bridges to cross before that one. 

Bridge One: Cylinders

I got s little start today so here it is. Two blocks of aluminum 1 1/4" square by 1 5/8" long worked out of a larger piece using the table saw and brought to dimension on the mill. 







The first task is to locate the center of the bore on opposite faces. This is not the center of the face; it is .500" from each of two adjacent edges. A 15/32" hole is drilled in each face for centering in the lathe






Yes, I know I could use a 4 Jaw chuck to hold the part but I haven't gotten around to ordering one for the lathe and I think my method is just as accurate and much faster. This is much like turning between centers. The headstock center that I will use is a piece of 1/4" rod on which one end has been turned a shallow taper. The rod is held in the 3 jaw and one end of the cylinder is seated on it. The tailstock with ball bearing center is brought up to the other end of the cylinder and used to force the 15/32" hole onto the tapered 1/4" rod and the jaws tightened.

When the cylinder is well seated on the rod, the 3 jaw is loosened slightly and the tailstock ram is used to drive the cylinder into full contact with the ends of the chuck jaws. The combination of the forced fit on the tapered rod and the pressure on the jaw faces may be enough to drive the workpiece but in this instance I add a little insurance by putting a piece of double sided sticky paper to the end of the workpiece before seating it on the rod. 

Sticky paper is just a square of printer paper that is sprayed with 3M adhesive and stuck on the workpiece. The other side of the paper is sprayed and when pressed against the jaw ends, provides additional traction. I have seen double sided carpet tape used for the same purpose but the paper is more stable than the cloth tape and is much easier to clean since I control how much adhesive to use.

Here is the piece in the lathe ready to turn the first flange:






Now to turn the flange without that anoying "THUMP-THUMP-THUMP" I take the biggest bite that I can. You can use HSS but I have come to rely on cheap brazed carbide bits that I have honed to a super sharp, thumbnail scraping, edge using a cheap $1 diamond wheel in my mini grinder. The brazed carbide chip limits the depth of cut to about 3/8" which sounds like a huge cut, but my 9x20 lathe has plenty of power to handle this cut and I don't think the smaller mini lathes would have a problem with it either. 

Why so deep? After a lot of experimentation, I believe that the magnitude of the "THUMP" is not so much a function of the depth of cut but is much more related to the amount of time that the bit is not in contact with the cut. If you only take a small cut, the bit will be in contact 10% and free of contact 90% of the time. As you get closer to a full round cut, the contact percentage increases until it is 100% and the "THUMP" decreases proportionally until it is gone. Taking the deepest possible cut results in almost no "THUMP" and you get to full round in only two passes. Don't take my word for it, watch the following video.





The job here is to turn a 1" diameter flange, 1/4" long on each end. To get the second end just reverse the work piece and repeat. Now, wasn't that easy?

Tomorrow, I'll try to get to profiling the rest of the cylinder and the valve ports.

Jerry


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## Captain Jerry (Sep 27, 2011)

Cylinders continued.

I got a little more done yesterday but I was falling asleep at the computer while posting last night so here is the rest of it. I hope it doesn't put you to sleep.

After the two flanges are turned, I grabbed one flange with the 3 jaw (loosely) and used the tailstock center to center the bore. I did set up an indicator to verify (you can see the mag base in the picture) and it was dead on. I then opened up the bore with a 1/4" bit followed by a 3/8" and then a 1/2" bit. 

This next step is a modification of the method that Brian showed on his "Overcrank" thread. I mounted a 5/8" bit and drilled to a very shallow depth, just deep enough for the corners of the flutes to penetrate the face. As Brian pointed out, if the bore is opened up to the full 5/8 diameter, you risk having the small drill bit wander into the bore while drilling the slanted steam passage. By drilling the 5/8' to a very shallow depth, it is easier to locate the starting point for the steam passage but you still have plenty of metal to prevent problems of starting and wandering.

Centered, ready to drill





Drilling 1/4"





After the 3/8" and the 1/2" drill its ready for the shallow 5/8" bit





Ready for the mill





I got so involved with the process that I forgot to take pictures but the cylinders were profiled in the mill by resting the flanges on the vise jaws and repeated milling passes followed by a small angular rotation through a total of 90 degrees and then touched up with a file to remove the ridges.






Now ready for the valve face and the steam passages. The next time I do this, I will drill and mill the valve before profiling the cylinders so I have a better grip in the vise. I still have one flat face that is 90 deg from the valve face so I can put that against the fixed jaw in the vise and slip a little packing between the flanges to keep the moving jaw from scarring them.

This post is long enough, and I've got some mowing to do. Florida grass is still growing. Next up will be the valves and if there is any interest, I'll show how I used Dockstaders great Zuener Diagram simulation to calculate the dimension. Its a lot easier than it sounds.

Jerry                                                                       628


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## joe d (Sep 27, 2011)

Captain Jerry  said:
			
		

> This post is long enough, and I've got some mowing to do. Florida grass is still growing. Next up will be the valves and if there is any interest, I'll show how I used Dockstaders great Zuener Diagram simulation to calculate the dimension. Its a lot easier than it sounds.
> 
> Jerry
> 
> ...


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## Brian Rupnow (Sep 27, 2011)

Jerry---Even in Canader, the grass is still growing. Your progress looks very good, and I too will be interested in your diagram.---Brian


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## Dan Rowe (Sep 27, 2011)

Captain Jerry  said:
			
		

> if there is any interest, I'll show how I used Dockstaders great Zuener Diagram simulation to calculate the dimension. Its a lot easier than it sounds.



Jerry,
I am always interested in valve gear discussions. I know how to construct a Zuener Diagram and I have used the Dockstader module but I do not find it nearly as handy as the Bilgram diagram which will give exactly the same answer.

The way to see the curves for this engine is to use the slip eccentric program. I know that you are not using slip eccentric but the curves will look the same as a nonreversing engine with the same port design and cylinder dimensions.

Dan


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## ronkh (Sep 27, 2011)

"I hope it doesn't put you to sleep".

Hi Jerry,

Not one of your builds has me anywhere near asleep and nor could cutting Florida grass compete with what you do.
Also, I am sure I could speak for the majority on here who must feel the same, but who do not always post a comment, that they love to watch talented machinists build these wonderful creations. 
I take the greatest pleasure in following these threads and to listen to the dialogue on the posted videos, as I do messer's Brian Rupnow, Chuck etc. Plus for Bogs comments and advice of whom I have made no replies to either. Perhaps it's time I did along with other "watchers"!!

Kind regards,

Ron.

PS, I have only mentioned a couple but there are so many talented people out there that I would have to mention almost every member!!

PPS. I have been a machinist for about 42 years and with some of you, I cannot compete on this scale.

Yet! Rof}


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## Captain Jerry (Sep 27, 2011)

The real problem with Florida grass is the almost daily rain. The grass barely gets dry before the next rain. There are 10 acres here so you have to get to it when the opportunity presents itself. Things will get easier when my helper gets up to speed. I need to make some riser blocks for the clutch and brake pedals.







I'm just taking a iced tea break and decided to check in on the forum. I'll get to the valve post tonight but it will be late so look for it tomorrow.

Dan, I don't know how a Bilgram Diagram works and I don't really understand the Diagram part of the Zuener Diagram. My first advice is to put away the compass and straight edge and just work the numbers. It will be a long post so I'll get to it tonight


Jerry


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## Brian Rupnow (Sep 27, 2011)

I like your helper Jerry!!! I have 3 helpers about the same age.


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## Captain Jerry (Sep 28, 2011)

Thanks to all who have expressed an interest in ANOTHER steam valve and my apologies to anyone who thought that I was going to explain how to construct a Zeuner Diagram. I can't.

What I said I would do is explain how I use Charles Dockstader's Zeuner Diagram to develop the dimension for this engine. I am not a steam engineer so when someone says "That would run better with a little more cutoff" I have to assume that he know what he is talking about. That's not really the problem that I need to solve right now.

Right now I have a steam chest whose internal dimensions are .850" long by .650" high. The corners have a .063 radius from the 1/8" end mill that was used to make it so I have about .625" of working space for the D-valve. How do I establish the correct dimensions for the valve and how do I tweak it for performance.

this is where Charles Dockstader's Zeuner Diagram comes in. I'm afraid that I don't know who Zeuner was or any of the history of his diagram. Early engineers often used graphical means to resolve complex relationships with multiple factors and to visualize the affect that changes in one or more factors had on the result. Today's "What if" scenarios are plugged into a spread sheet. The value that Dockstader's program has is that it combines an interactive spreadsheet like interface with a digital as well as a graphical representation.

If you don't have the Dockstader prorams, ask Google where it is. Fire it up and select the "Zeuner Diagram" option in the lower right hand corner.

This opens up a screen that looks like this:






Unless you are used to solving complex relationships with a compass and a straight edge, I would recommend that you ignore the diagram and concentrate on the parameters column on the left. Like this:






You can move any of the sliders in this column and see the effect that the change has. Ignore the diagram, it will drive you whacky!

Of the factors that you can change directly, only 4 are actual dimensions. 

   1. Valve travel  (equal to eccentric throw)
   2. Steam port width
   3. Bridge width  (distance between steam and exhaust port)
   4. Exhaust port width

There are 2 dimensions that you will have to reproduce but cannot directly change on this program:
   1 Width of valve  (width of D-slide valve)
   2 Width of cavity ( the width of the cavity in the face of the D-valve )

The other changeable factors are not direct dimensions. Changes to them will cause changes in one or both of the last two dimensions.

I hope no one says "well how about the length of the valve slots" to which I would have to answer "Huh?"

For reasons of simplicity, I will limit the width of the ports to end mills that I have and because of common practice, the exhaust port will be twice as wide as the steam port to allow for the increased volume of the expanded steam (even though I 
plan to use compressed air) so the exhaust port will be 1/8" wide and the steam ports will be 1/16" wide. That leaves only the width of the space between the ports to determine. I will arbitrarily start with a 1/16" bridge width. The total width of the three slots is 3/8" almost twice that amount of space inside the steam chest. That will probably work and I did not need any higher math or exotic diagram to figure it out.

If I make these changes to the Dockstader input screen, the screen will display a needed valve width of .585" and because the starting point for valve travel is set at .500", travel plus body width = 1.085" which will not fit within my steam chest.
I will have to change the eccentric.

If I grab the valve traver slider and drag it to the right left, keeping an eye on the valve width dimension, at about .165" of valve travel, the combination of travel and valve width falls to just under .600" which will fit my steam chest. If I reduce the valve travel to .150", the valve width drops to .429" and the cavity width to .251"

The default values of 80% cutoff, and .015" lead can be reduced to 95% cutoff, and .010" lead bring the valve width to .400". and additional changes to cutoff and lead show a corresponding chnge to valve width.

Changing the exhaust lap from .000 to .010 reduces the valve cavity dimension to .231"

With this information, I have the ability to tweak the valve anyway that I want and if I find the possibility to change from air to steam, all I have to do is change the D-valve. Nothing on the valve face changes.

I hope I have made sense of this. Its very late and my eyelids are banging shut so I may have left something out or misstated. I'll look at it again tomorrow and add any clarification needed.

Jerry


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## Maryak (Sep 28, 2011)

Nice one CJ :bow:

Just a suggestion but try 0.7 as the starting point for cut off and double the lead for the bottom of the valve to account for the angles and weight of the gear on the up stroke. You end up with 2 diagrams for 1 valve. If you leave the lead the same then the diagram is simply reversed through 180o to show the steam v exhaust on the other stoke.

Hope this helps.

Best Regards
Bob

PS If there is any interest I can start a new thread on how to construct a Zeuner Diagram


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## Captain Jerry (Sep 28, 2011)

Bob

Thanks for jumping in. I understand your suggestion up to a point, but I have some questions.

1. The calculations as I have used them, assume a symmetrical valve and gives a single solution as to the valve width. It also asumes that the cavity is centered in the bottom of the D-valve. If I change the cuttoff and lead, the width of the valve changes but the width of the cavity remains the same. So... to get the benefit that you suggest, the actual width of the valve should be the average of the two calculated values and the cavity is offset towards the top of the valve by the same amount. Is that right?

2. This modification would only apply to the vertical engine. Right?

3. The differences are extremely small at this scale and I'll be damned lucky if I can hit the mark. Right?

4. Unless I mark the top of the valve somehow, I'll probably assemble it wrong. Right?

5. I will have great satisfaction, knowing that I have designed the best possible valve. Right?

I am going to go draw this up and I'll post it for review. The digital solution, accurate to 3 decimals provided by Dockstader's program give far more accurate design dimension than I could get from a purely graphical construction.

If you have the time, I would like to see how a diagram is constructed.

Thanks for your input.

Jerry


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## Dan Rowe (Sep 28, 2011)

Jerry, 
Thanks for that explanation. I use the Dockstader Zeuner module the same way as even though I do know a bit of history about the Zeuner Diagram and I can construct one. I find the construction hard to master.

With a casting the bridge width is normally the same thickness as the cylinder wall to make a good casting. That does not apply here but I thought it worth a mention.

We were posting at the same time. I can to a step by step construction of the diagram. I have been thinking about doing a thread on the 3 most common valve diagrams.

Dan


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## Captain Jerry (Sep 28, 2011)

Bob

Here is a quick drawing of an asymmetrical valve. Note the different width of the valve faces with the wider face on the bottom. 






After thinking about this for awhile, if I want more push from the bottom of the cylinder to compensate for the weight of the frame, why would I reduce the amount of air or steam by increasing the width of that face. Do I have something backwards?

Jerry


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## Maryak (Sep 28, 2011)

Captain Jerry  said:
			
		

> Bob
> 
> After thinking about this for awhile, if I want more push from the bottom of the cylinder to compensate for the weight of the frame, why would I reduce the amount of air or steam by increasing the width of that face. Do I have something backwards?
> 
> Jerry



Jerry,

It's very early morning here, I am up because I have to be  Anyway this bit is important. LEAD is achieved by moving the eccentric and LAP is achieved by adding bits to the valve. For a D valve with outside admission that's why lap + lead = angle of advance, steam lap on the outer edge and exhaust lap on the inner edge. Lastly Lap + Lead is equal at the top and bottom. Lap can sometimes end up as a minus figure.

It takes a bit of getting used to but it's been stuck, (hammered), into my head since 1960.

I see Dan is going to show diagram construction which is great as I only know Zeuner so we all benefit from your and Chucks questions.

Best Regards
Bob

PS I will answer the rest of your questions, hopefully at the weekend.


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## Dan Rowe (Sep 28, 2011)

Bob,
I am wondering if making the valve different at the top and the bottom is worth the extra effort on a model.
Shays used square valves on a vertical engine and they were built in sizes up to 18" bore by 20" stroke. 

Pat, the best way to design a valve or choice of method is largely a matter of personal choice. I think most folks stick with the one that they first mastered.

Dan


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## Captain Jerry (Sep 28, 2011)

BigOnSteam  said:
			
		

> So if I haven't sold you on using standard scaled dimensions of a known valve and ports, plus a spreadheet to create displacement diagrams and verify valve events, then it is not for lack of trying.



Pat

You have certainly tried many times but I am not sold. If I understand what you are saying, Stanly had it right so all of us should follow that form. I'm sure that would work but it seems a bit restrictive to me. Does an automotive design apply to a constant speed mill engine? Have you posted the spreadsheet that you mention?

I don't mean to criticize your approach but I hope you understand that there are other valid methods. I find the Dockstader programs convenient, flexible, and useful. As far as I know, a Zeuner Diagram represents only event timing and makes no allowance for steam passage dimensions so that is for another discussion.

That's an interesting way to construct a displacement diagram. Does the paper have to move at a fixed speed or does it vary as a function of shaft rotation? The number of pens might be a problem. I don't think I can get that many mounted on this little D-valve. Couldn't I just use one pen and use line offset function in Alibre'?

Thanks for you interest and participation.


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## Captain Jerry (Sep 28, 2011)

On with the job at hand. I did get some work done today. Drilled the exhaust passage in the bottom of the cylinder, 9/64" diameter:






Milled the ports in the valve face, 1/8" exhaust, 1/16" steam, 1/16" bridge:






Set the cylinder block in the vise at the required angle using a protractor, 16 degrees and then used an 1/8" endmill to cut a flat seat for the steam passages. The endmill was eyeball centered on the 5/8" diameter ridge left by drilling the shallow 5/8" while still in the lathe. The steam passage holes will be 3/32" diameter so the endmill position was shifted 3/64" toward the outside so that the steam passage will clear the cylinder bore at the starting port. The endmill was sunk into the face of the flange to a depth of 1 RCH , again by eyball. The depth locked and then the "Y" axis was cranked .050" each side of center, forming a flat seat for the start of the steam passages. I was confident of the angle and the starting point so that the hole would intercept the milled slot of the steam port but I was less confident of the necessary depth so I set it by moving the "X" axis so that the drill bit cleared the edge of the valve face. I inserted a feelerguage into the port slot and brought the tip of the drill bit down to touch it and set the depth stop. Returning the X/Y back to the previous coordinates, I drilled the first hole without problem, Shifted the "Y" over .100" and drilled the second. Job done. Set up the other end and followed the same procedure. Looks like this:






or this:






Next up, the steam chests:

Jerry


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## Captain Jerry (Sep 28, 2011)

Steam chests:

Starting with rectangular plates .28" thick. The length is the same as the valve face plus twice the length of the valve rod spigot. The height is the height of the vlve face plus twice the height of the steam inlet boss.






Each face is centered and a shallow 1/8" dia hole drilled for the lathe centers.






Mounted in the lathe using the same method that was used to turn the cylinders. The first action is to turn the inlet boss on the top edge.






Then the valve rod spigot on the front and the back:






The spigot on the bottom is turned just to reduce the height of the block to the height of the valve face and then is milled off. As a final step the faces are faced to a .25 thickness with the valve rod spigot centered.






Time out, important phone call coming in. I'll continue later.

Jerry


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## Captain Jerry (Sep 28, 2011)

Progress will be suspended for a few days while I take a short trip. Nothing critical but an old friend has a boat that is taking on water at his dock. He needs help with the pumps until we can get it to a haul out point in the morning, about an hour's run at normal speed. May be slower this time. I'm leaving now.

Jerry


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## Maryak (Sep 29, 2011)

Captain Jerry  said:
			
		

> Bob
> 
> Thanks for jumping in. I understand your suggestion up to a point, but I have some questions.
> 
> 1. The calculations as I have used them, assume a symmetrical valve and gives a single solution as to the valve width. It also asumes that the cavity is centered in the bottom of the D-valve. If I change the cuttoff and lead, the width of the valve changes but the width of the cavity remains the same. So... to get the benefit that you suggest, the actual width of the valve should be the average of the two calculated values and the cavity is offset towards the top of the valve by the same amount. Is that right?



If I understand you correctly then YES



> 2. This modification would only apply to the vertical engine. Right?



YES



> 3. The differences are extremely small at this scale and I'll be damned lucky if I can hit the mark. Right?



YES, it's a lot of fiddle for very little return at model sizes.........see Dave's, (steamer's), comment re condensation and heat loss.



> 4. Unless I mark the top of the valve somehow, I'll probably assemble it wrong. Right?



What can I say ??? ;D



> 5. I will have great satisfaction, knowing that I have designed the best possible valve. Right?



You surely will


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## pcw (Sep 29, 2011)

Ken I  said:
			
		

> Both great looking designs - I'll be following this thread.
> 
> Great-grandfather - how are you so computer literate - I'm only up to grandkids and I'm stuck in a time warp of DOS based Acad10 - which I still use professionally - I'm a dinosaur.
> 
> Ken



hehe i am little more advanced using AutoCad 14 

great enigines, cant wait to see them finished. the overcrank i like best though.
pascal


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## Captain Jerry (Sep 29, 2011)

My Friends boat is saved and all is well. We did not need to haul out. Water was entering at the rudder post packing gland which is an in the water repair after we got the water out. The automatic bilge pump should have handled it but the switch failed. By the time it was noticed that the boat was low in the water, water was up to the floorboards and panic set in. I'll be back in the shop tomorrow. Here is some stuff that I didn't get finished posting.

Cylinder hone:

After the steam passages were drilled, the cylinder went back onto the lathe and was centered using the tailstock center and indicator. The bore was drilled with a 5/8" S&D bit in the tailstock chuck. It is a nearly new and sharp bit and the result was acceptable but a little honing will make it better.

The hone is a piece of hard maple dowel turned to diameter in the lathe for a length of about 3 inches. On either end oof the 5/8" working area, the diameter was reduced to 1/2". I covered the ways with paper and coated the hone with brasso.






The reason for the reduced area is to allow the cylinder to be pushed completely past the abrasive area on each pass. Each pass over the hone is at a steady speed and completely past the abrasive before being reversed and pulled completely past the abrasive area. This prevents any taper being caused by the honing process. Repeated passes were made until the bore was evenly bright.










Then I turned a piston out of cast iron and threaded #6-32 for the 1/8" piston rod. Mounted on the piston rod, and brought to final diameter and grooved for an o-ring. 

Sorry, no pics but nothing really new in this process. Now I have a question. Most, if not all of the cylinder wall contact will be with the o-ring. Should I leave the cylinder wall shiny bright or should I de-glaze it like you would do with a cast iron piston ring?

Jerry                                                                                             1564


----------



## robcas631 (Sep 30, 2011)

Capt,

They are both terrific and aesthetically pleasing. The design is amazing. Everyone here seems to come up with a design that is not only functional but revolutionary in design.


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## Brian Rupnow (Sep 30, 2011)

Jerry--for what you are doing, I would leave the cylinder wall shiny and bright. If you de-glaze it, the de-glazing stones will crosshatch a microscopic ridge pattern which will reduce the o-ring life. You want that de-glazed surface to help wear in the sliding surface of a metal ring. When using a rubber or nitrile o-ring, you don't want to do that.---Brian


----------



## danstir (Sep 30, 2011)

Thanks for the explanation of lapping the cylinder. I have read about it but your pictures helped make more sense of it. The simple oscillator engines I've built so far didn't need it, but I'm hoping to start building more complex engines.


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## Captain Jerry (Sep 30, 2011)

Brian Rupnow  said:
			
		

> Jerry--for what you are doing, I would leave the cylinder wall shiny and bright. If you de-glaze it, the de-glazing stones will crosshatch a microscopic ridge pattern which will reduce the o-ring life. You want that de-glazed surface to help wear in the sliding surface of a metal ring. When using a rubber or nitrile o-ring, you don't want to do that.---Brian



Brian, that is what I thought but a second opinion is reassuring.



			
				robcas631  said:
			
		

> They are both terrific and aesthetically pleasing. The design is amazing. Everyone here seems to come up with a design that is not only functional but revolutionary in design.



Thanks, Robcas631, that's what I was aiming for.



			
				danstir  said:
			
		

> Thanks for the explanation of lapping the cylinder. I have read about it but your pictures helped make more sense of it. The simple oscillator engines I've built so far didn't need it, but I'm hoping to start building more complex engines.



There are other, and perhaps more precise methods, but if the starting surface is straight and even, this is a quick and cheap method. Brasso works well on softer metals and I mix it with light oil for the final few passes. If the starting finish is uneven or deeply ridged, a reamer might be needed first. 

Jerry


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## Captain Jerry (Oct 1, 2011)

Good news...bad news...good news.

First good news...I have 3 days of nothing but shop time. My wife has gone with my daughter to visit my granddaughter at school. All the grass is mowed. All the horses have gone to the training center. Nothing to do but play in the shed. I ought to get a lot done!

Bad news... I left my camera in her car so it has gone to Tennessee with her. I could wait for her to get back or I could just plow ahead and tell you about it without pictures.

Good news... I did get a lot done today. I decided to plow ahead. I think that I will concentrate on the horizontal version and when I get the camera back I'll resume the vertical version. 

Today I got the cylinder and valve complete. I started to work on the crankshaft and connecting rod. The crankshaft is an ordinary built up design using 1/4" TGP steel for shaft and journal held together with locktite and pins. The webs are from 1/4" mild steel. To be absolutely sure that the shaft and journal holes are parallel, the webs were glued together with locktite and drilled and reamed as a unit. The mating faces were marked before they were glued together so that they can be assembled right. 

After they were drilled and separated, I faced the inner faces of the web, leaving a boss at the journal hole. This was done by putting the ball bearing tailstock center into the journal hole and forcing the web against the chuck jaw face as I have done on other parts in this build. I know this method seems odd to many people but it is quick, accurate, easy and safe. Three very light passes and I nice .030" boss , 1/2" dia. was standing proud on each face.

For this facing cut, I start as close to the center as I can get the tool without hitting the center and feed outward. This is a long interrupted cut so light cuts are a must. At one point, I got a little overzealous with the feed and the bit dug in and stopped the rotation of the part. I just eased off the cut, checked the pressure on the tailstock ram and continued. Nothing hurt, no underwear change.

If the part had been on a mandrel or in a chuck there is a good chance that something would have got bent or the part would have been ruined. I like this method of work holding and use it a lot. Crankshaft will be finished tomorrow.

On to the con rod and frame. The outer end of the frame has been a little fuzzy in my design, I wasn't quite sure how it was going to work. If I used a fixed shaft pin, I would have to build a split bushing and rod end. If I used a removeable pin, and a solid rod end with bushing, I would have to add a second connector bar for rigidity.

Here is my solution:












It will have a removable 3/16" pivot pin and a solid aluminum con rod end with a cast iron bushing.

The frame is very rigid. I had some worries. The rods are 1/8" SS threaded #6-32 in tapped holes in the piston end brace. The outer end of the rods will also be threaded but the brace will be drilled for clearance and secured with nuts so that it can fit over the crankshaft at assembly. The space for the nuts is a little tight. I think I will order some model scale nuts for a better appearance.

It has been a busy and productive day. Sorry about the lack of pics but I will show these parts and procedures when I get to the vertical model.

Jerry                                                                                                  1829


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## Brian Rupnow (Oct 2, 2011)

Jerry---I use your method of turning all the time, and it works good. It even works better if you buy a roll of carpet tape. (thats the kind with "sticky" on both sides.) and put a layer between the part you are turning and the chuck jaw face. It lets you take much deeper cuts without stalling the part. The tape is vry easily removed afterwards.---Brian


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## Captain Jerry (Oct 2, 2011)

Brian Rupnow  said:
			
		

> Jerry---I use your method of turning all the time, and it works good. It even works better if you buy a roll of carpet tape. (thats the kind with "sticky" on both sides.) and put a layer between the part you are turning and the chuck jaw face. It lets you take much deeper cuts without stalling the part. The tape is vry easily removed afterwards.---Brian



Brian - I have used the double sided tape but I can't always find it. Its here somewhere. For very small parts it is easier without the sticky stuff so I go bare or maybe a piece of paper, sometimes with spray adhesive on the paper.


I had another productive day in the shop. Finished the crankshaft. I couldn't find a soft nail and a drill bit that were close enough but I had a piece of 3/32" SS rod and my matching bit is nice and sharp and the hole is a tight push fit so that's what I used. 

I made several connecting rods before getting one that I liked. I was trying for a very light rod since there is no counterweight on the crank webs. This is a very short rod and a flat bar just looked heavy. Turned rods, even with fish bellies didn't look right either. I don't know of any precedent for what I came up with but since this is not a historical model, so I feel free to take some liberties. The structure is two parallel 3/32" SS rods with cast iron ends, split on the big end, plain on the little end. It is light and strong and carries the parallel rod theme from the guide frame.











Sorry about the lack of pics but models are better than nothing.

Jerry                                                                                           1979


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## Ken I (Oct 3, 2011)

Still better than a 1000 words Captain.

Ken


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## Captain Jerry (Oct 3, 2011)

Good news, my wife is home and my camera is with her.  She got home late this afternoon so I had time to get some pics of the project as it stands and some of the parts that are finished.

Here is the slide frame top end. The wrist pin is 3/16 TGP shaft rod freen in the brace and held in position with set screws at both ends.






Here it is in a trial fit on the guide rod frame.






Here the two bar con rod is fitted to the wrist pin and the crank shaft.






And this is the whole guide frame with crankshaft and con rod as it will be oriented in the vertical engine.






Before I can fit the horizontal engine I need the base and the bearing stands. I need to make some minor changes but I'll post the design before I quit tonight. 

Tomorrow will be a workout with the tablesaw.

Jerry


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## Captain Jerry (Oct 4, 2011)

This is the base that I will work on tomorrow. I want to try to achieve the appearance of a cast iron base common on small engines. A big part of that look is the sloped perimeter from the draft needed to pull the pattern from the mold and the lugs to bolt the frame to the floor. The angle of slope on this model is 10 degrees which might be a little excessive for draft but I'm not trying to be subtle. A pattern maker would use a table saw to get this slope on the pattern so thats what I'm going to use. It would be fairly simple if the base were just a rectangle but the narrowed section under the cylinder presents a special problem in the corner where the adjoining faces meet. 

The elongated holes are needed to clear the crank. I can't think of a method to slope these interior edges so they will be square but I don't think it will show.

The feet are just separate parts, fitted into milled slots.







Jerry                                                                                           2205


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## joe d (Oct 4, 2011)

Cap'n Jerry:

If this part is being made out of aluminum, you could do a finish pass on the edges of the openings
with a vertical panel-raising router bit.... could use the same bit for the outside as well so that the
angles match, would take some careful filing in the corners ;D

Joe


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## Captain Jerry (Oct 4, 2011)

joe d  said:
			
		

> Cap'n Jerry:
> 
> If this part is being made out of aluminum, you could do a finish pass on the edges of the openings
> with a vertical panel-raising router bit.... could use the same bit for the outside as well so that the
> ...



Joe - I did a search for that kind of bit but didn't find anything usefull. Can you point me to something? I used round ended slots in the design that can be drilled with a 5/8" bit but I have been thinking of changing that to square ended slots that might be more authentic and which I can slope with a file. I will probably leave the holes until after I have the bearing stands installed to be sure of location to clear the crank.


----------



## GailInNM (Oct 4, 2011)

Cap'n Jerry,
Looking good.
Tapered endmills are available for mold and pattern making. I have a selection that I have acquired over the years as needed and use regularly.
Many tooling supplier have them. Here is a link to Enco's page on them.

http://www.use-enco.com/CGI/INPDFF?PMPAGE=157&PARTPG=INLMK32

Gail in NM


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## joe d (Oct 4, 2011)

Jerry

Lee Valley Tools is where I get most of my router bits, but I see Gail has posted a source for the right tools!

Joe


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## Captain Jerry (Oct 4, 2011)

GailInNM  said:
			
		

> Cap'n Jerry,
> Looking good.
> Tapered endmills are available for mold and pattern making. I have a selection that I have acquired over the years as needed and use regularly.
> Many tooling supplier have them. Here is a link to Enco's page on them.
> ...



Thanks Gail, that would be the way to go if I thought I would last log enough to get a fair return on investment. I'm now thinking I'll mill it square and slope it with a file.

Here is what I did today.

Starting with a big chunk of aluminum 1.68" x 2.25" x 12" I'll rip a piece .4" x 1.68' on the saw. Using a 9" 60 tooth carbide tipped blade. I can't get the full cut in one pass. I have found that it is better to do it with 5 cuts. The first cut is about 1/4 of the thickness. Two cuts, one on each face, keeping the same face against the rip fence. The depth o cut is the set to just under 1/2 of the thickness and a cut is made on each face.  The blade is raised enough to complete the cut and one last pass separates the parts. Doing it this way keeps the part from getting too hot to touch. You must be sure that your rip fence is parallel to the blade to eliminate binding and friction.






With the slab cut to thickness, the blade is tilted to 10 degrees and the blank is cut to length. I cut it slightly over finished length. leaving just enough for filing to length. Next time, I would save this step for last, after cutting the shoulders for the narrow section. That would leave me room to make correction if I foul up the shoulder.

To cut the shoulder, the depth is set to cut to the wide part of the base and the miter guage is angled to 10 degrees. I clamp the part to a waste fence and the clamp the fence to the miter guage. 






 Cutting to the mark by eye is not that hard.






The mitre guage is swung to 10 degrees the other way and the second shoulder is cut to the same depth.






The blade is vertical for all of these cuts.

Now I'm ready to free the waste. Leaving the miter gauge set to 10 degrees. The part is stood on end and the blade depth is set to the length of the shoulder. Cut one shoulder, swing the miter gauge the other way and make the other cut. 






These last two cuts do not free the waste. The waste is still attached by a small amount of material in the corner. Break it free with pliers.






this is what is left in the corner.






Clean it up with a hacksaw:






and a file






and this is the result:






Now you can tilt the blade to 10 degrees and cut the long sides and the ends.

At this point, my eyes spotted my random orbit sander on the bench with a 100 grit disc. I wonder if that will give the appearance of a casting from a sand mold? I tried it. Maybe, I'll experiment with this later.






I then turned my attention to the two bearing stands. Nothing really spectacular here. I milled a piece of 3/8 thick plate to .300" thick, cut out two appropriate sized pieces, screwed them together through the center of the guide spool and profiled them on the mill.

Then the whistle blew and it was time to clean up and go home. I got a few mock assembly pics before I quit.






and






Its shaping up. Lots more to do but its beginning to look like the plan.

I'm beginning to get concerned about all of the unbalanced reciprocating weight without any counterweights on the crankshaft. Stew or Brian, did you find that to be a problem?

Jerry


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## Captain Jerry (Oct 4, 2011)

If you are comfortable with a table saw, thus is simple and straight forward. I have spent many hours with a table saw, making just this kind of special cuts (on wood) while under the watchfull eye of hundreds of spectators at woodworking demonstrations. I worked for both Shopsmith and DeWalt in my youth and have owned a number of table saws. This work was done on a cheap Hitachi portable saw. One of these days, I may get around to building a sliding table jig for this kind of cut but for now, clamps and a waste fence work just fine.

Aluminum can be cut on a table saw as easily as most wood and much easier than some. If you want to try something difficult, try this on a piece of gummy Georgia yellow pine.

If you are not as comfortable with a table saw, try it first on a piece of scrap wood. 

That chunk of aluminum is from my local scrap yard. Big chunks of top quality aluminum at great prices. If you are having a hard time finding a big chunk of aluminum for an engine block or some special project., give me a PM and maybe I can help.

Jerry                                                                                             2472


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## Brian Rupnow (Oct 5, 2011)

Jerry---I didn't noticie the lack of countetrewight as being a problem, but these are a slow running engine. What you are doing is looking very good.---Brian


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## kustomkb (Oct 5, 2011)

Great progress Jerry. It looks great!


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## Captain Jerry (Oct 6, 2011)

I made some more progress today but it was difficult what with stopping every few minutes to kick myself in the butt for the stupid mistake I made yesterday.  When I stopped yesterday, I had the bearing stands profiled and this morning I mounted the bearing caps and drilled the crankshaft hole on the line between the stand and the cap. This is not a finished bore. It is just going to be used for checking relative position and for locating the stands on the base. Later the bore will be enlarged and fitted with cast iron bushings.

The butt kicking is because, I misread or mis set the radius of the curve where the guide spools will mount. This is critical because the 30 degree slope on the face is tangent to this curve. Now when I positioned the crankshaft on the slope, it is spaced too far from the center of the guide spool. Kick butt. I can't just reduce the radius and re mill the slope because the bearing caps and the shoft hole won't work out. The only solution is to reposition the guide spool in correct relationship to the shaft bore and mill a new curve tangent to the slope. Got this worked out and here is the result






The only evidence of the mistake is the large tapped hole to the right of the hole at the center of the radius. I will call this a mounting location for an as yet unreleased future option.

I spent a little time reprofiling the brace blocks at both ends of the slide. They just looked a little too heavy.






The bearing stands are now positioned and mounted on the base so now I can mark out the clearance holes and get that job done tomorrow. Then I'll turn my attention to the guide spools.

A view from the top shows how tight the clearances are but it is going together nicely.






Jerry


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## Brian Rupnow (Oct 7, 2011)

Karma for you Jerry, for the great save and the great documentation. I'm enjoying your build.---Brian


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## SBWHART (Oct 7, 2011)

Wow Jerry you've certainly got a move on with this build, its looking real well.

As for the recipricating forces with my twin cylinder they were no problems at all, and Brians single ran well so i don't think you should have any problems.

I think you're going to have a real nice running engine real soon.

Stew


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## Captain Jerry (Oct 7, 2011)

sbwhart  said:
			
		

> Wow Jerry you've certainly got a move on with this build, its looking real well.
> 
> Stew



Moving pretty quick for an old guy. Would you believe, this is the first single cylinder engine I ever built? It goes a lot quicker without the extra cylinders and all that goes with them.

I got the clearances marked out an opened up the base to clear the crank:






I decided to taper the ends of the holes. I'll leave the sides straight. There is almost no way that will be seen through the works:






It started to look more like a casting and then I realized that if this were a casting, the whole top surface would not be flat. There would have been raised bosses for the mounts so that only those small areas would need to be surfaced, so I milled away about 1/16" of the top except where the cylinder and the bearing stands are bolted. This didn't show up well in the pics so I painted the dropped surfaces with magic marker so you can see it.






I decided to use four holes to mount the cylinder. Less chance of breaking into the bore.

Cylinder and bearing stands mounted on the raised bosses:






I turned up the guide spools from cast iron and parted off:






Sorry for the fuzzy pic. I'm not so hot with a camera. The cylindrical part of the spool is straight with no radius. It will limit vertical movement. Lateral movement is limited by the wide shoulder which has a nearly flat conical face so there should only be line contact with the rods. Here they are mounted inside the frame:






All clear, top-bottom-sides:














Friday night...Pizza and Beer!  Cheers!!                                                           2900

Jerry


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## Brian Rupnow (Oct 7, 2011)

Looks good Jerry. I kind of thought that this might be your first single cylinder build. I followed your "donkey" thread with interest, and then a bunch of swashplate type engines. This is looking really good.


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## Captain Jerry (Oct 8, 2011)

When I started this project, there was always the great possibility of failure. After all this is not a proven plan. It is an adaptation of a model and does not even follow the form or structure of the original model or even the form or structure of the simplified one cylinder version that Brian presented.

Well the possibility still exists but I have just past a major milestone. The geometry of the mechanism and the function of the reverse connecting rod are as good as I could possibly hope for, smooth, even, and amazingly friction free. No tight spots, no binding. The o-ring is not install on the piston and that will make a difference.

The distance between the two end braces is critical and the morning was spent fine tuning that and the piston rod length. The result is in this video.





The careful viewer will notice that the eccentric is not connected and might also notice the devining rod at the lower right hand corner that is providing the "force" but still, this is a major milestone.

Jerry                                                                                              3026


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## Harold Lee (Oct 8, 2011)

Jerry - you amaze me... Not only the creativity but the speed that you are able to make your model.. While you have built your model I have built two parts. My hat is off to you.

This is incredible work!!!! Thank you for sharing it.

Harold


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## Brian Rupnow (Oct 9, 2011)

Very nice, Jerry. Have you patented that devining rod drive? It might be the answer to our energy crunch here in North America!!! Beautifull work!!!---Brian


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## Captain Jerry (Oct 11, 2011)

Harold Lee  said:
			
		

> Jerry - you amaze me... Not only the creativity but the speed that you are able to make your model.. While you have built your model I have built two parts. My hat is off to you.
> 
> This is incredible work!!!! Thank you for sharing it.
> 
> Harold


Thanks, Harold. I'm working as fast as I can. So much to do, so little time.

Brian, if you think the devining rod is cool. check out the video at the end of this post.

I spent yesterday with the eccentric and strap. The eccentric is nothing special, just a cast iron disk with a single flange. The second flange will screw onto the face. This will let me use a one piece ecc strap. Well, not really one piece, it has a 1/8" SS rod with a plain steel pivot at one end and an aluminum circle at the other end. The inside diameter of the aluminum is shrink fitted with a thin cast iron ring to wear against the cast iron eccentric. 

I fiddled with the valve adjustment and was ready for an initial test. I flipped the switch to start the compressor and no response. The compressor is in the next room so I went to check it out. IT IS GONE. MISSING. DISAPPEARED.

I called my son-in-law to see if he new where it was and he said that he had taken it out to the training center (horses) because he had some carpentry to do. I reminded him that just because he owns the compressor doesn't mean that he can use it any time he damn well pleases!!! I'm going shopping for a compressor tomorrow.

Well, I was all set for a test so that's what I did. Here is the results:





I'm satisfied.

Jerry


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## kvom (Oct 12, 2011)

If you didn't have a compressor, how did you run it?  ???


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## Brian Rupnow (Oct 12, 2011)

Nifty trick, with no airline running to the steamchest. Are you sure you weren't involved with the original Godzilla movie?? nice looking engine.


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## Captain Jerry (Oct 12, 2011)

kvom  said:
			
		

> If you didn't have a compressor, how did you run it?  ???



Kvom - I didn't say That I ran it. I said that i tested it. I hope I didn't mislead anyone. The purpose of the test was to check the operation of the valve and the only way I could think to do that was to spin it in reverse and see if I could feel air pulses in the inlet tube. I hooked it up to my little unimat with a variable speed control and it pumped air just fine so I was satisfied.

Brian - My only connection with the Godzilla movie was laughing at the visible wires and the hokey effects. Is that what you mean't?


I went to Harbor Freight and bought a 1/3 HP 3Gallon compressor for $50. It ought to be good enough for inflating balloons and blowing chips off the bench and running an occasional low pressure engine.  I got it home, hooked it up an put the engine to the test. 

It takes a long time to upload videos to Photobucket so After dinner, I will show the results. Honest! No tricks!

Jerry


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## Captain Jerry (Oct 12, 2011)

The video is uploaded and ready for viewing.

I should apologize for rushing this engine to this point, it is not "finished" in any way. I just got so anxious to see it under power. I was concerned about the balance. I was concerned about the effectiveness of the guide spools and their location and would they provide the stability needed for the crank, or would the whole frame flop around at the end of the stroke. Well, now I know. It works just great. I am amazed at how well it works. In the following video, the base is just sitting on the wooden block to provide clearance for the 3" flywheel. At the hoped for slow speed operation, it just sits there. If I speed it up to about 250 rpm, it starts to slide back and forth but does not hop up and down.

here is the first run under air:





I think now that I know the design is sound, I can slow dow and pay a little more attention to completion. Once that is done, I can turn my attention to the vertical version. I look forward to that because it will let me proceed with confidence and put in place all the design refinements that I learned with this one.

Jerry                                                                    3478


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## Brian Rupnow (Oct 12, 2011)

Marvelous Jerry. A beautiful, well built engine.---Brian


----------



## kustomkb (Oct 12, 2011)

Man, what a nice engine Jerry. As you said, smooth and well balanced.

Beautifully made, and quick too.

Congratulations!


----------



## lazylathe (Oct 13, 2011)

WOW!!!! That was a super fast build!!!
And a very slick running engine Jerry!

Congratulations on Engine #1!!!

Can't wait for #2!

Andrew


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## Captain Jerry (Oct 13, 2011)

Brian, Kevin, Andrew - Thanks for the kind comments. There is lots more to finish this engine and if I can stop watching it for a while, I'll get on with it.

No engine test is complete in this shop without a run with the Big Baton. With this setup, I was able to bring the speed down to 54 RPM.





Jerry


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## Captain Jerry (Oct 19, 2011)

While waiting for some material to start the 2nd engine on this thread I decided to refine some of the parts that were hurried over in the rush to trial. You probably didn't notice the clunky over sized eccentric and eccentric strap. That is because they were carefully hidden from view and will remain hidden now that there is a new and much more presentable set. The new eccentric has been reduced from 1" diameter to .625" while retaining the .100" offset. The strap has been changed from a solid type to a split type and while I was at it I decided to try the style where the split is not at 90 degrees to the valve rod but is set at an angle, in this case a 20 degree angle. 

I first noticed this angled eccentric strap when I started the American Hoist Steam Donkey (as yet un finished but getting closer to re starting). And I have seen it on other engines as well. I'm not sure what the purpose of the angled split is but I have seen it most often on engines where the components are closely arranged so I'm guessing that it is an aid to assembly and service in tight quarters.

In any case, I like the look so here it is:







I also decided to put a little bend in the rod. This necessary because the valve and the eccentric do not line up. This could have been remedied by putting the eccentric inside the shaft bearings but I wanted to keep the engine compact and I wanted the bearings as close together as possible. I made the pivot joint with an offset but due to miscalculation, the offset is not enough, it still needs a bend.

This style of engine (over crank/back acting) brings the crankshaft closer to the cylinder so the valve linkage is also shortened. The length of rod between the pivot and the strap is only about 1 inch and the offset is only about 1/8". The rod is only 1/8" diameter so just put it in the bench vise and bend it. No problem until you try it after threading the ends. Threading concentrates the stresses and maybe eve work hardens the stainless steel so after breaking two rods in the attempt, a light went on and I annealed the rod after threading and the the bend was easy. Here it is:






This is so much more in more in proportion to the rest of the engine that I can now show it without the flywheel on that side. It also shows off the lug feet on the base "casting".






Now I will have to do something about the mounting.

Jerry


----------



## steamer (Oct 20, 2011)

Awesome build Gerry!  I like the feet and the angle split eccentric.

Nicely done!  :bow:

Dave


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## Maryak (Oct 20, 2011)

Very Nice CJ, :bow:

I well remember our discussions over bending the eccentric rod on the donkey engine. ;D

Best Regards
Bob


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## Ken I (Oct 20, 2011)

Very nice Captain, I like your choice for asthetic reasons.

So fast as well - keep up the good work and the posts.

Ken


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## steamer (Oct 20, 2011)

Maryak  said:
			
		

> Very Nice CJ, :bow:
> 
> I well remember our discussions over bending the eccentric rod on the donkey engine. ;D
> 
> ...




As do I!  :big:

Glad that's old hat now!

Dave


----------



## Captain Jerry (Oct 20, 2011)

Bob, Dave, and Ken - Thanks for your support and encouragement. This has been a fun project and surprisingly easy. No real setbacks or surprises except for the extra tapped hole on the bearing stands but I'm working on a cover up for it. 

COMING SOON - AT THIS LOCATION - ENGINE NUMBER TWO - THE VERTICAL!


Jerry                                                             4265


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## SBWHART (Oct 21, 2011)

Great Job Captain, some interesting design features in their woohoo1 woohoo1 woohoo1

Looking forward to No 2

Stew


----------



## CMS (Oct 21, 2011)

Very nice, really enjoy watching all the extra moving mass, adds eye appeal.


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## Captain Jerry (Oct 25, 2011)

I'm about ready to start #2. The table has been a problem for me. Dimensions, proportions, material, style just haven't been working, at least not for this design. To my eyes, its just a little too fancy, requiring lot of detail and bling, and brass and the idea here is just to take the back acting mechanism from engine #1 and present it in a vertical design with minimal changes to the working parts, so ... while browsing in the scrap yard, I scored a 5" length of 4" OD aluminum pipe. It seems to make a more compatible engine design. Not really a table, but a vertical engine anyway.

What do you think?

Jerry


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## Maryak (Oct 25, 2011)

Jerry,

To be honest, I'm not sure that I like it all that much and if you have to ask us, then I suspect that you too have doubts.

Best Regards
Bob


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## kvom (Oct 25, 2011)

I like your version on page 1 better.


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## Captain Jerry (Oct 25, 2011)

Bob, Kvom - Thank you for the responses. Its not that I just ignored them. Its just that I spent all day hacking away at that piece of pipe before I got a chance to read them. Now I've got sweat invested so I'm going to continue with the pipe version. It won't take long. This is a really easy engine to build and I already have the cylinder about half done from earlier in the project.

I have some pictures of today's work on the camera that need to be uploaded so I'll post the progress later tonight.

Jerry


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## Captain Jerry (Oct 26, 2011)

The first thing to do to the pipe was to set it up in the lathe. Both the inner and outer surfaces were crusty but the cutoff end was clean and nearly square. I was able to grip it with the inside jaws and coax it into alignment with some hammer taps. The surface was too crusty to read with a DTI so I just used a tool in the toolpost and rotated the chuck by hand until I got constant contact through a full revolution. 

The diameter was to big to fit in the steady and I was not going to power up without some outboard support so using a VERY sharp tool on the inside diameter and rotating the chuck by hand (belt tension off), I turned a clean contact area about 3/8" deep from the outer end, and also faced the outer end square. Then I reversed the part in the lathe and did the same process at the other end. It sounds tedious but it only took a few minutes.

Now that I had a true inner face, I turned a 3/8" thick disc to a tight push fit and now I had a place to put the live center for outboard support and could power up the lathe and turn the outer surface, just deep enough to remove all of the warts and gouges. It only took a few thou to get a nice clean surface from end to end.






Now I have to figure out a way to hold it on the mill. I've got a 3 1/2" pipe and a 3" vise. My two tiny V-blocks won't help any. I resolved it by opening the vise as wide as it would go and using a table clamp to hold the pipe down. The pipe does not bottom out in the vise. Now I'm ready to mill something.

If I hadn't been paying attention when Stew Hart showed how he cut the popcorn engine trunk crosshead guide, I would have gone about this all wrong and made a mess of it. Thanks for the tip, Stew.

Here is how it works, just mill a notch deep enough to penetrate through to the inner face.






Do that on both sides and then use a hacksaw to remove the waste.






The purpose of the rectangular plate bolted onto the cylinder is to index the cylinder when it is rotated to do the other side and to set the depth of cut for the endmill so that I end up with two upright columns that are centered, parallel, and of equal width.






Finish off the filet with a 1/2" ball nosed end mill.






I still need to mill the shoulders for the bearing supports and to mill the openings in the two remaining faces to create the four column structure. That's for another day.

Jerry                                                                      4616


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## Shopguy (Oct 26, 2011)

Jerry
I like the way you are turning that piece of pipe into what should be an attractive engine frame. 
Ernie J


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## Captain Jerry (Oct 26, 2011)

Thanks Ernie, I guess the jury is still out on how attractive it will be but it's beginning to take shape. Even after taking most of the waste off in chunks, there is an amazing amount of swarf coming off of this thing. The shop is a mess.

This is a picture left over from yesterday. Today's pictures were the victim of dead batteries in the camera.






I won't get back to the shop until Monday. I'm going to visit with some old sailing friends who have gone ashore and headed for the hills of eastern Tennessee.

Jerry


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## Captain Jerry (Nov 2, 2011)

Full day in the shop today. I made lots of chip but it was very slow progress. Here is the end result:






Four notches to support the bearing beams and two openings through the pipe to give the four columns.

Not much to say about the notches. They are .75" by .28" but holding the pipe which is big for this mill is a bit of a challenge. Here it is held on the surface of the vise and held parallel to the X axis by the raised edge of the vise jaws spread open. A tall clamp reaches over the base to hold it down. The four notches required 4 separate setups because the "Y" axis travel is limited by the mounting of the "X" axis scale behind the table so I was unable to do two notches with one setup. There are other ways that I could have set the part and used the longer travel of the "X" axis but it would mean removing the vise.






The rest of the day was used up cutting the two openings in the sides that are 1" wide and 4" tall. I had been thinking (fuzzy) that I would remove most of the waste with overlapping drilled holes but by the time I got the part clamped in the vise and held by two other hold down clamps, I had only about 1" between the part and the chuck. The only drill bit that I could get in the chuck was a centering drill so thats what I had to use to make the first entry into the hole. I could then get a 3/16" endmill in the hole. I had more overhead clearance when I switched to the R8 collet for the endmill but that is the largest endmill that I could get in the hole. I now began to make 4" long passes in a clockwise rotation around the slowly widening hole until it was the 1" wide needed. 

This was a very long and slow process because I was making cuts the full depth of the material (about 3/8") but with only .030" DOC.  The setup was as stable and rigid as I could get it but the top of the part was more than 4" above the table and the head was at the upper end of the "Z" travel and although I was able to find a speed/feed rate that did not produce much chatter it was slow, dull, boring, repetitive cranking of the table. It was so dull that I almost fell asleep at the job. Really! The final few passes around the perimeter of the cutout were made with a 1/2" diameter end mill to provide the filet at the top and bottom of each column.

I was not willing to risk any greater depth for fear of ruining the part. Partly because of the time already invested in this part but also because there is no replacement for it. This is a big chunk of aluminum at scrapyard prices but I didn't see any more like it at the scrapyard and way more oney that I want to spend to order new on line.

I know a picture would be nice, BUT, when I got home from the shop, I went to get something out of the trunk of the car and when I was closing the trunk lid with the hand that was also holding the camera, something happened and the camera fell from a height of over six feet to the concrete driveway. 

The camera still works, as far as I can tell, but the mem chip and the batteries popped out and now the chip refuses to give up the pictures that were stored on it this afternoon. Sorry. The only evidence that I have for this day's work is the picture at the top of this post of the progress made on this part.

I have another chip so there will be ore interesting stuff to come. Next up are the bearing support cross beams that have a fairly large arc on the bottom edge that I don't know for sure how I will do it. Maybe the boring head, maybe a fly cutter.

Jerry


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## Captain Jerry (Nov 4, 2011)

On the way to the shop this morning, I was thinking about how to produce the arc at the bottom of the bearing support beams and not even thinking about what would prove to be the biggest problem of the day. But first, I have to fit the beams to the base. A little touch with the file to be sure that the beams fit flush in the notches and then beam and base drilled, counter bored, and tapped #4-40 for a 1 1/4" SHCS. Turns out the longest #4-40 SHCS in the bin is only 1" long so an odd mixture of screws are filling the job until I can get to the fastener shop. Looks like this:






Now the big challenge becomes obvious. The overhanging ends of those beams need to be made flush with the curve of the base columns. All sorts of bad ideas came to my head, like hacksaw and file, disc and belt sander, but those thoughts were just putting off the obvious. It needs to be done on the lathe.

I can get a good grip on the base with the inside jaws but the beams are 5 inches out from the chuck and an interrupted cut at that. The outboard end needs support. Here is the final setup:











The aluminum disc fro the bottom is moved to the top, under the beams. The center hole has been enlarged to 3/8" and an oillite bushing pressed into it. A 1/4" tool steel rod is held in the tailstock chuck and the bushing turns on the rod. I was just mucking around, looking for inspiration and not at all sure that this would work out but when I put a DTI on it I was only about .012" out and with a few taps with a block of wood, I had it down to less than .002". I didn't think it would hold up to the interrupted cut but I thought I would give it a try. There was almost a 1/4" overhang on the ends of the beams so I could take a few passes and check again. This demands a sharp tool and a light cut so I touched up the tool on the diamond wheel and set a cut of .005" and had a try. I am using brazed carbide tools that are honed to a razor sharp edge with no top rake, minimal front relief, and a small radius on the tip. In the past I would have used HSS for this job but since I have learned how to shape a carbide tool effectively, I rarely use HSS. 

On the first pass, only one beam end was sticking out far enough to take the cut and there was considerable pounding but when I checked the run out afterward, It had not moved. so I continued taking cuts of .005" until all four beam ends were flush with the cylinder. The I made a few passes on the full length of the cylinder at .002" DOC so everything was fair.






End of challenge. Piece of cake. I think the biggest challenge with jobs like this is overcoming fear. By this time, Ive got a lot invested in this part. 

Now I can get to the job that had me worried all night. The curve on the bottom of the beams:






The hatched area needs to be cut away in a nice smooth circular arc. I got it done but it was not what I had planned. Its now after midnight and the story is to long to finish tonight. More tomorrow.

Jerry


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## SBWHART (Nov 4, 2011)

Good job, and a nice set up well shown and explained.

Thanks for showing

Stew


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## Captain Jerry (Nov 4, 2011)

sbwhart  said:
			
		

> Good job, and a nice set up well shown and explained.
> 
> Thanks for showing
> 
> Stew



Thanks for the comments, Stew. I was surprised at how well it worked out. I' getting better about figuring out how to get these unusual jobs done. Most of the time, the setup that works is not the one that I had planned the night before. I know that is from lack of experience. The arc on the bottom of the beams shown above is a good example.

Usually, when I encounter a long curve like this, it is an outside curve but on an inside curve like this there is no place to put a center pivot unless I bolt or clamp it to a larger plate. That was plan #1 and could have worked out if I had a plate big enough. Clamping would have to be worked out but I didn't have the necessary plate so on to plan #2.

Plan #2, Boring Head. My little 2" head doesn't swing a wide enough circle in the normal setup with the boring bar vertical, but there is a horizontal hole in the head that would swing a wide arc but when I started trying to work it out, it seems that I would have too have a reversible mill or left hand boring bars and a big dose of courage to make that work. I rejected the idea of a flycutter for reasons of courage. That's a big arc to swing.

Plan #3 involves using the rotary table but my table is only 4" so I would need a carrier plate or I would have to find a way to mount the cylinder on the table. That's the path I chose. The part is too big or the table is too Small to get a good clamping solution so I put a threaded rod up through the center hole and clamped it with a bar and nut across the top. I had to raise the base of the table to clear the nut on the bottom and use the outside jaws on the table to position the cylinder. All of that got pretty tall but R8 collets don't take up any Z so I have just enough room.  

Positioning was not difficult. The center of the table must be centered under the spindle on the "Y" axis. The "X" axis will be used to adjust the depth of cut. The part must be centered on the RT in the "Y" as well. The "X" axis position on the table sets the center of the arc. That must be a thousand words, here's a picture:






A 3/16" end mill and moving the table to the right in small increments with repeated passes to bring the cut to final radius.






Job done. Easy.

I'm off to the shop. Upper bearing block with guide spools is next on the agenda.


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## Ken I (Nov 4, 2011)

Cap'n - I once flycut a 9&1/16 radius using a flycutter - mounted a boring bar with HSS tool through the horizontal hole in the boring head - set the radius and went for it.
I was young and stupid at the time and all the old hands said it wouldn't work - but it did.

This was on a Bridgeport - the job was an Aluminium dipole mount for the centre of a radar dish - eliptical about 6" long and 2" wide with the 9&1/16 rad in the face an approximation of the parabola at that point.

Got a lovely finish as well.

Chance favours the brave (and possibly stupid) - a cutter sticking out that far is damn dangerous.

Ken


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## Captain Jerry (Nov 5, 2011)

Ken, I sometimes wonder why we fear big swinging cutters like that. I guess its just natural. After all, you don't intend to grab the thing! Fifty years ago, when I was learning how to demonstrate woodworking machinery in public, my instructor gave me some guidelines that I still rely on.

1. Know where BOTH hands are at all times.
2. Do not lean on the machine.
3. Know where your hands AND the part will be when the cut is finished.
4. Swing the cutter once by hand and be aware of what the cutter path is.
5. Be sure all guards are in place, but treat the machine as if it has no guards.
6. Have confidence, you don't want to scare the customers.
7. Don't joke about lost fingers, bad karma.

Woodworking machinery can be particularly dangerous because most of the time, you are holding the part in your hands and pushing it towards the cutter. Running a two bladed milling cuter with an 8" radius at 3400 RPM (basically a big flycutter) taking full profile cuts on a radial arm saw was an every day occurrence.

Now, on with the engine. Today's progress was just straight forward sawing and milling and drilling and counter boring and tapping but there were no critical or unusual setup problems to show. The result is that both upper halves of the bearing supports are installed on the cross beams. 






The small hole in the center of the top radius is where the cast iron guide spools will be mounted. The crankshaft bore is located on the parting line between the beam and the top half. Tomorrow that will be drilled and reamed for the CI bushings that the shaft runs in.

This is a short post during halftime, Alabama vs LSU. The games starting up again, tied 3-3.

Jerry


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## mklotz (Nov 5, 2011)

> 2. Do not lean on the machine.



Although a bit OT and not a safety issue, I want to add to this. Next time you have an "I don't really care that much" piece mounted on the lathe, try leaning on the headstock. I don't mean touch it but rather lean the way you might lean on the bar after three Glenfiddichs at the local watering hole. Curse me if you won't see some interesting patterns in the workpiece assuming that you're using power feed.

The lesson: don't lean on the lathe/mill while trying to make a precision cut.

.


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## Captain Jerry (Nov 6, 2011)

Just a small job but I can make it last all day. Crankshaft bushing are needed. The shaft shouldn't run in the aluminum frame and since I'm avoiding brass or bronze for this project, I'm going with cast iron. I toyed with the idea of split bushings but that's not really needed here. Here are the pics






Upper left - Cast Iron              Upper right - Cast iron without the rust and pipe threads drilled 15/64"

Lower Left - Turned to 3/8" for .28"    Lower right - Parting off.






Here the bushing is pressed into the frame (Thumb Press):

I couldn't resist the urge to see how things are shaping up, so after hand reaming the bushings in the frame, I stuck a flywheel on a short shaft and gave it a spin. These CI bushings are slick, maybe better that oil-lite bronze. I couldn't stop there so I placed the unfinished cylinder in the base and propped the guide frame on a bar for this positional mock up.






Its beginning to look like an engine. If you compare this guide frame to the frame on the horizontal version, you might notice that the assembly nuts are not showing at the con-rod end of the frame. They have been moved to the piston end of the frame and the guide rods are threaded into blind holes in the top bracket. This will be a big focus point on this engine and I wanted to give it a cleaner appearance.

Crankshaft coming next.

Jerry


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## Captain Jerry (Nov 7, 2011)

Well, I got a little more done today. The target was a crankshaft but it didn't quite get finished. I did get the webs finished but not yet glued or pinned to the shaft. They are a little different than those on engine #1. The lesson learned on #1 is that there is no room for counterweights. To make room for counterweights would mean moving the crankshaft further from the piston and that is counter to the purpose of a return crank engine which is to get the shaft as close to the cylinder as possible or more accurately, to get the piston as close to the crankshaft as possible.

On engine #1, when running at low speed 100-200 RPM the out of balance condition is not noticeable but at 300-400 RPM, the engine begins to slide back and fourth due to the unbalanced reciprocating mass of the piston, rod and sliding frame. Not much I can do about that on a single cylinder engine. At over 600 RPM, the engine starts to hop up and down. This is due to the unbalanced rotating mass of the crank webs and the connecting rod. Balancing the web and con-rod forces is the function of counterweights which are usually part of the crank web but can be added to the flywheel. That works fine on a dual flywheel engine but0 if added to the flywheel on a single flywheel engine it introduces a new off balance.

One thing that would help is to reduce the mass of the web and con-rod. The two rod con-rod on engine #1 is about as light as I can get it but I can reduce the mass of the webs in two ways. I can reduce the volume of material in the webs by careful profiling.  I used the crank web style that is shown in this link:

http://www.shipsnostalgia.com/guides/William_Doxford_and_Sons

That shows the works of the William Doxford and Sons Ship Building. If you haven't seen these pics, be prepared to spend some time gawking. See if you can tell which pictures of the webs are at Doxfords and which ones are of the webs for engine #2 in my shop.






If you have trouble telling the difference mine are the ones in the pictures that do not include very small people. Here is a pic of the webs positioned on the shaft:






One other thing that I can do is to change from steel to aluminum. I know this may be controversial. I have seen aluminum used with full disk or large profile webs but I don't think I have seen it with small profile webs like this. I still think it should work. This is a low power, low impact steam engine and the web/shaft joint will be assemble with steel pins. Tell me if you have tried this and had a bad result. If it doesn't work, I can always make another one out of steel. It will just mean another day spent doing what I like to do.

Thanks for watching and thanks for your comments.                                             5580

Jerry


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## Captain Jerry (Nov 9, 2011)

Pardon me for rushing. I really want to finish engine #2 before the end of the month. Holiday commitments, family visits, and trips to visit family will make it difficult to concentrate much after that. In addition to that, I got a call from an old cruising buddy who wants me to help him identify all of the damage that a lightning strike has done to his boat. The insurance co. is sending a surveyor but this is a good chance to hang out on the boat and sample some rum. This is the third time his boat has been hit. It is alongside his dock at his house and this time it got the house as well. Electronic thermostats and sprinkler controls are shot.

Back to the engine. Working on the crankshaft. The locktite has sat overnight so I can cut away the shaft between the throws and grind the stub ends of the pins and generally clean it up.











Next up is the con-rod. As on Engine #1, It will be a double bar connecting a split cast iron big end and a one piece cast iron small end. The CI for these parts was salvaged from a cheap import drill press vise that broke from over tightening.




































These pics are pretty much self explanatory. I'm in hurry-up mode and the setup pics are suffering but this is very repetitive from engine #1 and I don't want to bore anyone and drag this out.

But if there are any questions about any of these shots, just ask and I will give more of an explanation.

Thanks for watching.                                                           5762

Jerry


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## Brian Rupnow (Nov 9, 2011)

Jerry---your work just keeps getting better and better. Very nice.---Brian


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## Captain Jerry (Nov 27, 2011)

Hello All, I just wanted to say that this project has not been abandoned. I just haven't been in the shop for a few weeks. I have been in a big hole in the ground, wondering how I got there. This is a 15' by 35' concrete swimming pool that has not been resurfaced in 40 years. No structural defects but the surface is full of hairline cracks, some of which have pitted and a few spots that have spalled to the concrete surface. Pressure wash, acid wash, pressure wash, grout, epoxy sealer and top coat. I am just about finished with the grout phase and so I will be at it for a few more weeks before I can add this to the list of things I have never done before and will never do again.

Jerry


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## Captain Jerry (Dec 22, 2011)

For the past few weeks my shop time has been limited to short visits and the camera work suffered but I was pushing to get the second engine running so I could put it out of my mind for the holidays. The functional details of the vertical engine are the same as the horizontal one so It was just a matter of getting the fiddly bits done and adjusted. The only thing that is really different is the mounting of the cylinder and adjusting of the cylinder rod. Since the cylinder can't be moved, all adjustment must me made at the rod/slide frame connection. I was slightly short on the cylinder but I thought I could recover by reducing the piston thickness. I got it worked out but it is very close to hitting the head at either end. As it stands, there is a slight tap at one end of the stroke but I can't be sure whether it is the piston hitting the head or maybe a little slop in the valve rod knuckle. Anyway, The Vertical Back Acting Engine Makes it first public appearance:






I got a few ore videos to show but uploading is slow at the moment. More later.

Jerry


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## Brian Rupnow (Dec 22, 2011)

Very, very nice Jerry. Well done!!!


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## Captain Jerry (Dec 22, 2011)

Brian

Thanks for the comments. There is still more to do on both of these engines. Proper piping is clearly needed and maybe even a governor and certainly som clean and buff. Neither of the engines have any gaskets on the heads or steam chests but I may just play with them as they are for a while until inspiration strikes.

This is about two engines so here they are together:





And here they are* connected *together:





Jerry


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## SBWHART (Dec 23, 2011)

Real cool Jerry very well done two nice engines 

Stew


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## Ken I (Dec 23, 2011)

Very, very nice Captain - I know the feeling - once you get 'em turning over, you're loath to tear them down again to do the refinements.

I can'y open the You Tube video on my steam driven Win98SE PIII so I presume you have coupled them at 90° - to make it self starting.

Ken


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## Captain Jerry (Dec 23, 2011)

Stew

Thanks for the kind comment. My son-in-law stopped by during the photo session and was surprised when I told him the engines weren't finished. "Looks finished to me. What else do they need?" So I showed him your finished Popcorn engine. "Oh, can you do that?" he asked. I could only try, maybe.

Ken

Thanks for the comments. I connected them at 90° using a piece of tubing over the shaft. Self starting of course! The videos are hosted on Photobucket. Can you open other vids or is it just these?

I have to say that this has been one of the most enjoyable builds I have done. It had some challenges but no disasters and the end result is two engines that run better than I had hoped. The honor of having the project highlighted on the masthead for November makes it all the better.

Jerry


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## Path (Dec 24, 2011)

Very impressive ... I can only hope that I will be able build something like these. :bow:

Although I do like the vertical the best ... a little more unusual.  

Looking forward to the finishing touches.

What could be next? 

Pat H


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## Captain Jerry (Jan 6, 2012)

I hope you don't mind a little update on the vertical back acting engine. I saw a thread on making globe valves with the PMResearch kit and that reminded me that George Brittnel had posted a thread sometime in the past about buillding globe valves from bar stock so I looked it up. Great stuff! 

I didn't have the right stuff on hand so I got some ordered. I couldn't wait for the delivery so I started without it. Only enough stuff for one try and I didn't follow George's design exactly. George used a very small screw ( #0-80 or #1-72) and while my eyes are still good enough to see them on the bench, my fingers hate them and send them to the floor where they love to hide so the smallest thread on this valve is the stem thread, which is a #6-32, a very manageable size for me. I built a 90° style with side outlet which is much easier that the 180° with side control knob. When I get the ordered material, I'll try the 180° and maybe a gate valve as well. Here is a pic of the valve on the steam chest of the vertical engine. There is not room for a flanged mount so it is joined with a close nipple threaded #10-32.







I immediately discovered that this gave me far better control of the engine than I had using a cheap regulator in the air line. One of the features of steam engines is low speed torque which allows a load to be started and accelerated smoothly without the need for a clutch or low ratio gearing. It is difficult to demonstrate this on a small model and I was never able to demonstrate that in the past. 

Here is a short video of the engine connected to a 5.5 to 1 step up gearbox, spinning my big brass baton. Since this is a single cylinder engine, the crank must be set a few degrees past TDC to get it to start, but it starts smoothly and accelerates slowly to about 100 RPM and can be controlled to run smoothly at about 25-30 RPM. Turn your sound up!

If anyone is interested in the globe valve, I can post a new thread after the supplies arrive next week.





Thanks for watching                                                             7539

Jerry


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## dsquire (Jan 6, 2012)

Captain Jerry

Very nice. When you give it a bit of air to start it seems to step right into it and make a nice pull to speed. Even more impressive knowing that it is 5.5 step up with that heavy weight to spin. :bow: :bow:

Cheers 

Don


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## ozzie46 (Jan 6, 2012)

That sound majestic!! Love it.

  Ron


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## arnoldb (Jan 6, 2012)

:bow: Very nice Cap - I really like the way it runs so slowly !

Regards, Arnold


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## Ken I (Jan 6, 2012)

Love the throttle addition.

Ken


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