# Another Paddleducks Build



## kvom (Apr 28, 2009)

I have abandoned the CO2 engine, as I have come to believe that the laws of physics will prevent me from getting it running. Some things don't scale up well.  

I think I will have a go at the Paddleduck plan Bogs posted on HMEM. I'l let this thread be a placeholder until I actually make some parts.

My current idea is to scale it up by 1.5 times and use Imperial threads and fasteners (I have a lot of 5-40 and 6-32 screws and nuts). I will also use non-metric drill rod in places where that's called for. Otherwise I will just multiply the dimensions by 1.5 and convert to inches. I have a DRO on both the mill and the lathe, so odd numbered lengths shouldn't be a problem.

I will also go somewhat for the "bling" look. I probably won't try the separated cylinders as I don't yet have a good rotary table, and as I will be running it on air and not steam I think I can skip the displacement oiler. I'm pretty sure I have enough scraps lying around for most of the pieces (I plan to do the block in steel rather than cast).

I've skimmed through the "book" once, but now I'm going to read it more carefully before starting out. The printer is going as I type.

And of course I also have shred's build thread to reference.  :bow:


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## steamboatmodel (Apr 29, 2009)

"I will be running it on air and not steam I think I can skip the displacement oiler."
Remember that the engine will still require lubrication. One of the fellows in our engineering group builds fantastic models of steam engines, but only runs them on air. He uses the FRL (Filter Regulator Lubricator) units from Air Tools with them and has no problems.
Regards,
Gerald


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## kvom (Apr 29, 2009)

OK, I have one part made to justify this thread. I decided to tackle the eccentrics, as the technique in the book is interesting. I also had some suitable sized steel cutoffs.

In interpreting the plans I calculated that 1.5mm = .059", so any dimension needed is quickly calculated needing to remember only one number. So the diameter of the eccentric is 18mm -> 1.06".

The initial turning to length and cutting the end flange and groove were not too difficult. I recently acquired a very veteran B&S height gauge and a cheap ENCO granite surface plate, so that I was able to measure the lengths and face to the desired dimension fairly easily, if slowly.

I don't have a rotary table, but I used the following setup clamp the disc in the mill vise and to find the center quite rapidly:







The indicated 5mm hole defines the diameter of the crankshaft, and so would fall between 1/4 and 5/16 inches. I happened to have some 1/4" drill rod, so that's the size it will be. That said, I can always enlarge the hole should a thicker crankshaft be needed.

Then my trouble of the day started, as my run-of-the-mill automotive class die was incapable of cutting a 1/4-20 thread in the end of the hardened rod. So I had to resort to trying to thread the rod using the lathe. Once the threading tool cuts through the hard layer the interior of the rod is a rather gummy steel that resists cutting cleanly. So after any number of tries I finally got some partial threads cut and was able to finish them with the die.  Then it was a matter of bolting the eccentric piece against the face of the 5C collet/block as shown here:






The reason for this setup is that the 6-jaw vise won't tighten on a 1/4" rod, so this is my "collet chuck" setup for small rods. The chuck is very accurate, so that the runout with this setup is quite low. It's necessary to really tighten the collet when taking the interrupted cut or else the rod will just turn in the collet jaw. My turning technique was to touch the lathe tool to the innermost point of the boss and set the DRO y-axis to zero. Then when turning I could watch the DRO count down and would know when to stop the cross feed, which was running at the lathe's slowest speed of .0006/revolution.

So after 4 hours work I have 1 part to show:






I used a lock washer under the bolt, which scratched the surface a bit. For the next one a flat washer might be better.

And of course as soon as I was finished I remembered that I had a piece of 1/4-20 threaded rod that I *could* have used instead of threading the drill rod.

At least I'm "underwauy" roj:


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## shred (Apr 30, 2009)

Cool.. 1.5x is going to be a good two-hand size with lots of bling opportunities since some of the parts will have extra meat on them when scaled up. Weird your drill rod wouldn't thread-- it's usually soft as shipped and I've had no troubles until I hardened it. I do usually turn it down a little to match the correct thread diameter, which helps a lot.


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## kvom (Apr 30, 2009)

The rod was air-hardened as ordered. In any case, today I fabricated the other eccentric using the threaded rod. It went much faster, about an hour start to finish.

I then went through the book noting the dimensions, calculating the 1.5x dimensions and writing them on the pages, and comparing these to the brass material I have on hand. It seems I either have pieces that are too small, much too big, or else I need to make a part to fit another part that gets made first.

However I do have a number of pieces of 1/4" thick brass sheet that was originally 3" wide. Since I now had the eccentrics made it seemed logical to make the straps next. I found two pieces that were reasonably close to the top and bottom sections, squared the sides on the mill, measured each with the height gauge to calculate how much needed to be milled off, and then milled both to the calculated size.

The only point of interest to a reader might be this "technique" for clamping a part in the mill that is thinner than your parallels:






These hardened precise cylinders are also useful in ensuring proper clamping when the surface against the moveable jaw is not flat.

Once both pieces were sized and precisely squared, I drilled the holes for the screws. I am using 6-32 screws. Once the top piece was drilled and tapped, and the mounting surfaces deburred, I screwed the two tightly together and camped in the vise in order to bore the hole. 

The diameter of the groove in the eccentrics is ~.830, so I wasn't going to be able to find a "lucky fit" drill bit as Bogs did. So after edge finding to locate the center of the bore, I center drilled and drilled through with the 1/2" drill bit. Then I remembered that I have a .75" end mill, and used this to enlarge the hole further. Then I had to resort to the boring head to reach the final dimension. I recently acquired a set of bore gauges, and these were immensely useful in measuring the bore with the piece still in the vise. I used Bogs' tolerance of .05mm, which is ~.002.

Next I used a 1/2" endmill to reduce the thickness of the strap (still screwed together) to fit the width of the groove in the eccentric, taking equal amounts on both sides. This also cleaned up the surface on the sides.

When assembled onto the eccentric it turned, albeit stiffly. Some lapping and run-in should take care of the fit (I hope).

Then I reclamped the top portion in the vise to drill the holes for the coupling. It seems that 3/16" rod would be a bit too big, so I drilled it 5/32. Then drilling the oil hole completed the day's shop activity. Here's the result of about 5 hour's work:


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## shred (Apr 30, 2009)

kvom  said:
			
		

> I then went through the book noting the dimensions, calculating the 1.5x dimensions and writing them on the pages, and comparing these to the brass material I have on hand. It seems I either have pieces that are too small, much too big, or else I need to make a part to fit another part that gets made first.


That happens even with the regular-size plans.. lots of convenient metric dimensions are just a leeetle larger than common imperial stock; at least the stock in my scrap pile. If I'd really gone through the plans, I might have tweaked them some in that regard. The biggest chunk of material by far is the main block, after that the control valve and valve blocks, then the bearing blocks.

Next up for me happens to be boring the eccentric straps too.


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## bearcar1 (Apr 30, 2009)

Yer off to a good start KV, Thanks for sharing with us. Keep after it. :bow:

BC1


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## kvom (May 2, 2009)

I spent a couple of hours in the shop after dinner starting on the packing gland.

For the screws, I decided to use a diameter of 15/32 so that later, when I need to turn the flange to fit the cylinders and drill for the piston rods, I will be able to hold the glamd in a collet rather than the chuck. The thread is 3/8-16. I had no real issues turning the screws as I had a piece of 1/2" brass rod to start with.

I then turned the gland itself, with the inner diameter 15/32 to match the screw, and the outer diameter 1", turned from a piece of 1" brass rod (took .001 off for finish). Then drilled and tapped to match the screw. After parting there is enough extra length left to turn the inner boss for the cylinder bore.

My only "problem" is that the screw won't go in all the way, because the tap won't cut enough threads (pointed part is too long). If I can find a bottoming tap at school I'll fix it that way; otherwise I can always shorted the screw portion.

Thoughts?

I finished only one gland, so the other is on the agenda for next time.


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## Metal Butcher (May 2, 2009)

Don't know if its a good idea, but I solved the long point problem on a few taps with my grinder. I ground for less than a second then dipped in a container of water. This kept the temperature from messing up the taps hardness. The pointy ones do seem to need a trim.

Wish I had a dollar for every screw I had to shorten. Then I could afford more boxes of various screw lengths! ;D

-MB


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## deere_x475guy (May 2, 2009)

I have done the same thing with a few of my taps also when I break one it becomes a bottoming tap.


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## bearcar1 (May 2, 2009)

Been there and done that many times as well. Unless a bottoming tap is available, grinding one down is my choice as shortening the screw lessons the clamping pressure supplied by the smaller fasteners. That's just my $.02 on the subject. 

BC1


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## shred (May 3, 2009)

With a packing gland that's where the packing goes so it's not such a problem, but otherwise the bottoming tap is where it's at. 

If you have enough thread, you can also turn down the end threads on the plug. Sometimes the problem is the threads on the plug aren't completed by the die. The trick I've used there is to flip the die around backwards and finish the threads.


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## kvom (May 3, 2009)

> The trick I've used there is to flip the die around backwards and finish the threads



Did that too. I ground down the tap this morning, and now the screws go "almost" all the way in, probably .01" gap left. I'll try a little more grinding on the tap, and then maybe a bit of filing on the end oif the screws.

I turned the other gland and tapped it. Then had to attend to family affairs. Still need to drill the mounting holes in the flange and mill the flats on the screws.

I also found a place on some cut up brass plate where another crankweb could be cut, and turned that. So one more to go.


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## kvom (May 4, 2009)

A little progress this afternoon:

Reading through the book I noticed that the valve packing gland is almost identical to the piston gland (flange is a bit smaller). So since the 1" round stock was still chucked in the lathe, I turned two of these. I left the flange diameters to be turned down when the boss for the bore is turned.

I found out that my class is cancelled for tonight, so I won't be able to get any more brass material until Thursday, unless UPS arrives with the 1/2" bar I ordered.

I decided I could make the plain pipe flange from the 1" round stock. I chucked the bar in the billing vise using v-blocks and cut the flats wide wide enough for two flanges. Then I chucked the bar in the lathe and drilled it assuming 1/4" pipe.






Then it was just a matter of turning it down to the correct diameter and parting off.






Looking at the photo it seems they're slighly unbalanced, but I can correct that when it's time to drill the mounting holes.

Given the larger size, I'm wondering if brass will be strong enough to make the long flanges. I may try to make a couple.

Both of my packing gland screws need to be redone. One isn't straight, and the other got gouged cutting the flats. Since I need identical screws for both the piston and valve glands, I will be making 4 of them. I plan to mill the flats for all 4 before doing any lathe work. That way I can hold the bar with a collet in the square collet block.


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## SignalFailure (May 4, 2009)

Re unthreaded bits... I've ground all my taps (2mm-6mm) so that they are virtually bottoming taps and never had a problem. Mind you I've never used Aluminium so not sure how I'd get on with that metal 

A useful technique when the thread doesn't go all the way to the underside of the head on a screw is to cut a 'shoulder' (i.e. a groove) directly under the head to it will screw all the way in. A blade-type parting tool or pointy HSS bit is useful!


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## kvom (May 4, 2009)

Spent the evening making 4 identical packing gland screws. Mounted a 1/2" brass rod securely in the square collet block in the milling vise. This allowed me to mill flats on opposite sides for all 4 screws. The flats fit a 3/8" wrench.






Then I chucked the bar in the lathe and turned the OD to 15/32. Then for each screw:
 - turn the end section to be threaded to .370" for 3/8-16 threads
 - undercut the end of the threaded section at the head
 - single point the threaded section on the lathe to a thread depth of .06"
 - finish the thread form with a die
 - test fit to a glad for good measure
 - part off

Took about 1:15 for the 4 pieces


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## kvom (May 6, 2009)

I don't have much to show for 4+ hours of work.






My first goal was to mill the brass to size for the conrods, but I was having all sort of problems with the finish. After changing endmills a few times without success, I noticed a little light on the control panel of the VFD : *rev*. I had been running the spindle in reverse.  :hammer: This is not something that would be likely to happen using the normal mill switch. Either I left it in reverse after boring the eccentric straps in back gear, or I fat-fingered the button (which is right above the *run* button. As I was running the mill at 2000 RPM I didn't really notice that it was turning back-asswards.

So after wating a fair amount of time I did manage to mill the brass to size, center drill the ends, and drill/ream the holes at 1/4". My intention is to turn the conrod like John's, between centers. Since I need to borrow a lathe dog from school to do this I'm leaving the rest of the milling for afterwards.

I then decided to make the crosshead guide bars from some 1/4" drill rod. After some calculations on dimensions I settled on drilling and tapping the ends for 6-32 screws. Rather than mess around with the collet blocks to hold the rod, I switched to the rubberflex collet chuck. Drilling the rods was not much of a problem. However, when I attempted to tap the first one still chucked, I broke my automotive-quality tap off in the hole. I was able to extract the tap, and decided to tap the rods later using the mill as a tapping station. This rod didn't take will to parting either, as once the parting bit is halfway through the rod snaps off, and also causes the chucked end to bend at the chuck jaws. So after the first one, I just used the DRO to mark the length, parted just enough to show where to cut, and cut it off with a hacksaw.

Now that I had the 4 drilled pieces, I proceeded to tap them at the mill. The first two went fine, but on the third I snapped off my only remaining, good quality, 6-32 tap. So that was then end of that for now.  :bang:

I decided it was time to take a break. 

Perhaps I need to anneal these rods before tapping!?


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## shred (May 6, 2009)

kvom  said:
			
		

> I don't have much to show for 4+ hours of work.


I know the feeling.. 


> So after wating a fair amount of time I did manage to mill the brass to size, center drill the ends, and drill/ream the holes at 1/4". My intention is to turn the conrod like John's, between centers.


Did he do them between centers? I sort of assumed he stuck them in that self-centering 4-jaw he has (which I am mildly jealous of) and turned them with that.


> Perhaps I need to anneal these rods before tapping!?


Probably a good idea. My drill rod turns and taps fine in it's 'au natural' state


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## kvom (May 6, 2009)

> Did he do them between centers?



I meant turn them as opposed to leaving them square bars.

According to the Enco site, there are two types of drill rod. I think I ordered the "water hardened", where I possibly want the oil hardened type.


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## kvom (May 7, 2009)

This morning I attempted to machine an eccentric coupling fork. Unfortunately when I started to mill the slot I discovered that a 1/4" slot is too wide. It scales to .236. And in addition my 1/4" end mill is slightly oversize as well. So on to a redo with the 1/8" endmill. On the bright side I came to undestand that it's quicker to square off the stock for both forks at the same time and then cut them apart.  :smart:

I had an excellent trip to school this afternoon to discuss my engine issues with the instructor, and to borrow some needed gear. So to total it all up:

- He recommended that for tapping the drill rod for the crosshead guides, I should drill the hole with 1 or 2 sizes up on the drill bit and somewhat deeper. That will lessen the chance that I will break the tap (and I got a new tap to try it with).

- borrowed a 1/16" slitting saw on an R8 arbor for slitting the crankwebs. Here he suggested that clamping all 4 of the discs together and slitting them at one time might make for a more rigid setup. By leaving the pins in the holes used for milling level, the setup can be the same, and the pins removed as the saw blade nears the hole. He suggested slow RPM and slow feed.

- Borrowed 2 lathe dogs for turning the conrods between centers (looks as if either will work). I also got a piece of steel from which I plan to make an adjustable dog that fits my chuck.

- scored a piece of brass plate 1/4" x 3" x 8" that will serve to make the bottom plate, the 4th crankweb, and some of the other smaller plates as well.

- Found that the block of mystery brass alloy in my lockers is large enough for the block, and possibly even two of them. Another piece of the same allow can make all 4 bearing blocks.

- The 2" round silver brass that Cedge gave me will get a slice cut off for the flywheel.

So it looks as if I am set for material except for the top plate. But there is a fellow on eBay who sells pieces that will be suitable.

Nothing stopping me at the moment but lack of energy.  

Here's the result of the evening's efforts. Two forks for the eccwentric coupling. Haven't drilled the holes for the pins as yet.


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## shred (May 7, 2009)

kvom  said:
			
		

> This morning I attempted to machine an eccentric coupling fork. Unfortunately when I started to mill the slot I discovered that a 1/4" slot is too wide. It scales to .236. And in addition my 1/4" end mill is slightly oversize as well. So on to a redo with the 1/8" endmill. On the bright side I came to undestand that it's quicker to square off the stock for both forks at the same time and then cut them apart. :smart:
> ...
> - He recommended that for tapping the drill rod for the crosshead guides, I should drill the hole with 1 or 2 sizes up on the drill bit and somewhat deeper. That will lessen the chance that I will break the tap (and I got a new tap to try it with).
> ...


Later in the text, John explains why he calls for drilling deep holes then tapping them-- to save on swapping out taps. You don't have to tap them all the way to the depth listed by any means.


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## kvom (May 7, 2009)

Shred,

Can you point to where the "adjusting screw" between the fork and the valve is described?


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## kvom (May 8, 2009)

I did some measurements and discovered that I indeed have enough brass for both the top and bottom plates, so as of now the only material I am missing, AFAIK, is the correct diameter drill rod for the spool valves.

My first task this morning was to cut the ~6"x3" bottom plate blank out of a 9x4 piece of 1/4" brass. I could have done this on the bandsaw, but decided to mill it out with a 1/8" endmill. It took longer, but in the end I wasted less material. From the cutoff, I then cut out a piece big enough to turn the disc for the 4th crankweb. My boo-boo was to crank it a little too hard and broke the endmill. Luckily it's a double ended mill, so I still have one to go.

I was going to post in detail about another fubar I did, but I'll just summarize it by stating that when tapping a hole, look to see that you do indeed have the correct size tap in the tap wrench.  :hammer:

After lunch I tackled the crankwebs, now that I had all 4 discs cut out. Drilled the holes and pressed in the drill rod. I am using 1/4" for both shaft and pin:







My little arbor press was handy here. Milled the first side:






I used a 3/8" ball-end mill to get the rounded inner corner. Then the other side:






All ready to be slit:






I'm not sure whether to drill and tap the lock screw before slitting.


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## shred (May 8, 2009)

kvom  said:
			
		

> I'm not sure whether to drill and tap the lock screw before slitting.


I drilled right through for the tapping drill, then slit, then clearance-drilled (the bolt heads on mine are above the surface, Bogs counterbored his) with an old broken slitting blade in the slot to stop the clearance drill from going too far. That worked ok except for the time the old blade was in the wrong spot and the drill pulled straight through. If I had better drill downfeed control (must make a stop one of these days), I'd probably clearance drill & tap before slitting. You can go a little over on the clearance drill without too much trouble, but leave plenty of area for threads.

The adjusting screw (a bit of threaded rod) is mentioned in the drawings, and later in the text where it says in passing that it will be silver-soldered to the fork end. I'd make it a tad longer than the specs call for-- one of mine only has a few threads engaged-- you also may want to go easy on the silver solder or re-thread the filleted part if you need those threads.


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## bearcar1 (May 9, 2009)

Great looking crank webs KV. I think that I would opt out for drilling and tapping them before you slit them. It would provide a a more stable piece for that step and it wouldn't hurt a thing. Keep up the good work. :bow:

BC1


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## kvom (May 9, 2009)

Yesterday evening I had squared up the base plate and flycut the top surface. As it was still in the vise this evening I continued to drill the holes in the plate. After center drilling all of them, I came to the conclusion that the scaled metric screw for the bearing blocks was between a 6-32 and an 8-32 SAE. Since these are not visible, I decided to go with the larger screw. I used a #20 drill bit for the 8 inner holes, leaving ~.003" clearance. Since my parallels were under the points for the perimeter holes I decided to defer drilling these. I'm not sure how I will be mounting the finished engine. 

I then proceeded to slit yesterdays crank webs using the borrowed slitting saw/arbor. This went nicely and quick fast. I used the same drill rods in the holes to clamp the webs parallel to the top of the vise jaws. The mill was running in back gear at 200 rpm with a feed rate < 1ft/min. The exposed radius of the saw was "just" enough to reach the small end hole.

Having been out and about in the sun all day I decided I was sufficiently tired to call it an evening, before I did something silly.


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## kvom (May 11, 2009)

I spent a few hours today starting on the engine block. It took some time to square it all up as the material doesn't like big cuts or fast feeds. Too fast and it throws off dark chips and smoke. In addition it creates a lot of tough burrs, so lots of filing to debur the edges after milling each side was necessary.

The dimensions ended up right on for thickness, and about .100" large on height and width. Based on the material I have, the steam chests may be somewhat thinner than spec, so I am planning not to adjust the block width until I can measure them.

In any case, the cylinder bores are positioned relative to the center lines, so I proceeded to drill these. I am going to leave the bore at .500, which although somewhat less than scaled, is the size of my largest reamer. Were I to bore it to .590, the displacement would be 3.375 times greater than the original. As it is, the displacement will be 1.907 times.






I was concerned that scaling up the steam holes from 1.6 mm might not work, as I would presumably want the area of the opening to be approx. twice as large. Since a hole with twice the area is .089" in diameter and a hole 1.5 times 1.6mm is .094", it seems irrelevant.


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## kvom (May 12, 2009)

After milling the main block, I was determined to make the rest of that bar serve for the steam chests and bearing blocks, as I have no other thick brass. 

The piece destined for the steam chests was just wide enough for two, but I was afraid that if cut on the bandsaw one piece would be too small. So I used the slitting saw to slide it in two on the mill. I can say that the level of "chatter" was more like a scream, but feeding at less than 1 ft/min at 300 rpm finally got the job done. After squaring the two resulting bars, I found that the height would be less than scale, but still enough for the computed valve bore with a decent amount to spare. I then milled one side to the proper width, but left the depths unchanged. Given that the datum lines are center lines, I can drill all the holes and clean up the depths at the end (I might possibly need to reduce the depth of the block slightly as well). 

The remainder of the material was 1x1", meaning that the depth of the bearing blocks will be slightly smaller than scale. Before I mill the width I need to calculate an allowance for the smaller than scale crankwebs.

So not a lot to show in finished parts, but a lot of time spent on the mill.

The scale for the valve bore is between 5/16 and 3/8, so I will need to order some drill rod. Luckily Enco is running a free shipping + 10% discount the next two days.  ;D


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## kvom (May 14, 2009)

Not having any bar stock large enough for milling the crossheads, I did some calculations and found that I could get a block cut from some 2" round stock. I still has a chunk of mystery brass alloy that Cedge gave me, so I cut off a 1" slice on the bandsaw and milled it into an ablong block. This was yesterday; today I decided to continue. I didn't get far.  :big: As I was drilling one of the holes for the guides, I noticed a hot spot on the side of the block. Seems this metal gets hot when drilled, and actually melted at the bottom of the hole:






Since I also had a piece of 360 brass 2" rod, I went to Plan B and repeated the milling operation. Once I had the first block, I calculated that it was 62% of the original disc:






Here's the machining sequence for anyone that's interested. First, since the sides of the disc are reasonably straight, I chuck the disc in the vise with one side flat against the fixed jaw and mill one face flat to remove saw marks. Next I reverse the disc with the flat face on parallels and mill the other face. Now I can clamp the two flat faces on the vise jaws and mill one side (after calculating how much to cut). This flat side is then clamped flat on parallels to mill the opposite face. I now have something that looks like this:






I then use a square to clamp it vertically.






Once I had an oblong block it was a matter of *carefully* drilling and milling the crosshead out of it. I didn't find the optimum milling sequence, but all was fine in the end.






Hopefully I'll finish the other one the next time in the shop.


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## kvom (May 16, 2009)

Rather than finish the other crosshead, I decided to work on the bearing blocks that I had roughed out last week. It was tedious work, but nothing fancy. The vise stop saves a lot of time in repetitive operations on multiple parts. I did drill the oil holes before reaming the bores so as to avoid burrs.

For turning the bosses on each side, I used the same fixture I used for the eccentrics: a piece of aluminum round drilled and tapped 1/4-20. The first one turned out poorly, with a lot of tearing. I was using a medium speed and slow machine feed on the crossfeed. This alloy needed just the opposite: lots of RPMs and fast feed. Here's the results:






I did discover a potential problem. I drilled the holes for mounting the blocks on the base plate according to the plan. However, the material I had for the blocks was smaller than spec, so the blocks ended up .18" shorter in the longest dimension. Fortunately the blocks cover the holes, but using the planned 8-32 screws to attach them will mean that the tapped holes in the base of the block will be extremely close to the edges. I think I will just use 5-40 screws, leaving more "meat" around the holes. However, I'm going to sleep on it before making any decision. I could conceivably drill a second set of holes in the plate inside the ones I already drilled. In any case, I have not drilled mounting holes in the base of the blocks.

Any other ideas are welcome.


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## Maryak (May 16, 2009)

kvom  said:
			
		

> I think I will just use 5-40 screws, leaving more "meat" around the holes. However, I'm going to sleep on it before making any decision.



Kvom,

Reads like that's the best option.

Best Regards
Bob


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## kvom (May 17, 2009)

My first goal of the afternoon was to finish milling the second crosshead. I did it in a different sequence, and although it required an extra reclamp in the vise, I was able to clamp solidly against the jaws more often. The first operation was to expose the conrod bracket (three cuts in one vise position):






Then two cuts on the "cheeks":






Afterwards it was just the cross cut on the Y-axis and milling the slot.






After patting myself on the back and enjoying a soft drink, I drilled and tapped the bearing blocks.






There was just enough room for the 5-40 screws. Right now the bores are a tight fit on some 1/4" drill rod that I lapped with some fine sandpaper. I need to do the same thing with a longer piece to lap out the bores and align the blocks precisely on the plate, as shown in John's writeup.  I'd like to get the base cutouts done next so that I can trial fit the eccentrics and cranks.


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## kvom (May 18, 2009)

Thanks for all the advice. I'm actually looking foward to trying it. I'll use the citric acid as it sounds simpler and safer.

Today I had a couple of hours in the shop before going off to school. Ny task today was the cutouts on the base plate.  I started by measuring the faces of each of the bearing blocks with an edge finder. I then used my height gauge scribe to make very faint marks on the plate. These were just as checks on where the cutout corners are supposed to go. Since I was going to use a 1/4" endmill, I spot drilled each corner 1/8" in from the computed dimensions, using the scribed lines as a check. I then drilled 1/4" holes (end mill is the type with the small hole in the center, hence not useable as a dril).
Here's the result:






Next I made all the horizontal cuts using the table feed:






The Y-axis slots I had to do by hand.






After deburring the edges I remounted the bearings to check my work. I looks as if I will need to slightly enlarge under one of the bearings a bit.






I had a little time left, so I drilled and tapped the lock screws for the crank webs (did I ever mention I hate tapping?)


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## shred (May 18, 2009)

you'll get lots of tapping practice, like it or not.. I think there are 50+ screws and attendant tapped holes on this thing.

Clearance around the bottom of the bearing blocks is also a good thing-- if the crank rods stick out even a little, they have a habit of banging into any protruding baseplate bits.


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## kvom (May 19, 2009)

I had a few hours today interupted by several honey-dos. Got the steam check holes drilled. I am going to hold off on reaming the valve bore until I'm ready to fit the valves. I decided to go with a .375" bore and ordered some drill rod of that size today. In any case I drilled the bore 1/32 smaller. The steam ports are .177". The flange mounting screws will be 5-40. I didn't tap these yet (did I mention I dislike tapping?). For mounting the steam chest to the block I will use 8-32 screws, hence the mounting holes are drilled accordingly.






I also made a flywheel from the Cedge mystery alloy (silver bronze). It's hard to work with, but is very "pretty" when polished. I used the badsaw to cut off a 5/8" slice from the 2" diameter rod, but since the saw didn't cut straight the wheel ended up .55" thick rather than the scale .59". I wanted to machine a rim/hub recess, and normally would use a parting tool. However because the cross slide on my lathe has a very short travel, the parting tool in the QCTP holder won't go close enough to the center. So I needed to grind a HSS tool blank into an appropriate cutter. That took quite a while, but gave me a chance to use the new 46-grit grinding wheel for the first time. I plan to bling it up a bit, but here's the first version mounted up for a trial fit:


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## Maryak (May 20, 2009)

Kvom,

Really starting to look the part now. :bow:

Best Regards
Bob


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## kvom (May 21, 2009)

Today I decided to make the upper plate, as I had limited shop time available. I started with a 4"x4" piece of .25" thick brass plate that had been flycut on one face. After squaring the sides I used a 1/8" endmill to saw the short side, then used an endmill to bring to the final dimensions.

Since all of the holes are or can be referenced from the center, drilling them was an exercise in cranking the handles and watching the DRO. I drilled all of the mounting holes to take 6-32 screws. The large holes for the glands needed to be slightly over 1" in diameter. I used a 3/4" end mill (my largest) to make the initial hole, and then the boring head enlarged them to ~1.05 (loose fit around the gland).

I didn't make any cutouts as I want to see how the plate looks when mounted before deciding on any blingification.






As I was taking the photo UPS arrived with my 3/8" drill rod, so machining the valves may be the next task.


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## kvom (May 22, 2009)

A full afternoon's work in the shop resulted in exactly one useable part:






The two other valves that I started ended up in the scrap bin because of various operator errors. On the positive side I did learn the best way to turn this rod to get a better finish, and I can probably make a valve in less than half an hour if I don't mess up.

I decided that the lathe karma was lacking, and decided to move to the mill for a "simple" piece, the blanking plates. Well I messed up there somehow as the holes didn't end up centered. So I figured it was time to call it a day.

As for wiggle room, I think I need to plan for that on the steam chest/blanking plates. I drilled the holes with a #20, which is a close fit for an 8-32 screw. Using the DRO to drill the holes for the plate, I found that the screws would "just" go through the plate and the steam chest. I plan to enlarge these holes by a couple of thousands so that when attached to the block I will be able to wiggle them slightly in case the bores on the block and steam chest are not perfectly aligned.


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## PhillyVa (May 22, 2009)

kvom,

Don't you love it when you learn something new every day...today you made one part, tomorrow one more part and before you know it you'll have a sweet little engine.

By the end of it and when you start the next one there will be more challenges but less mistakes, better parts = nice engines.

Keep it up :bow: the good work...by the way :bow:

Regards

Philly


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## shred (May 23, 2009)

The valves were one part I botched a number of times too.. I think I made four through various stages and got two usable ones


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## Maryak (May 23, 2009)

kvom  said:
			
		

> A full afternoon's work in the shop resulted in exactly one useable part:
> 
> I can probably make a valve in less than half an hour if I don't mess up.



See you gained quite a bit but sometimes it sure doesn't feel like it. 



			
				kvom  said:
			
		

> I decided that the lathe karma was lacking, and decided to move to the mill for a "simple" piece, the blanking plates. Well I messed up there somehow as the holes didn't end up centered. So I figured it was time to call it a day.



An excellent decision, trust you imbibed some suitable fluids to maintain your electrolyte balance. 

Best Regards
Bob


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## kvom (May 23, 2009)

Here's the summary pic of today's progress:







Got the other valve made, although it took longer than the half hour I estimated yesterday. I also reamed the steam chest bore to .375" to match the valves. Of course now it's a press fit at best, so some lapping is due there.

The same is true for the block, where I re-reamed the bores to .5" to remove the burrs caused by drilling the steam holes.  I then drilled the holes on each end for attaching the steam chests. The afternoon finished with turning the pistons, which are likewise a press fit and require lapping.


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## kvom (May 26, 2009)

I had a couple of "days off": Sunday my daughter had invited 15 or so of her closest friends to have a party to celebrate the end of the school year, as well as to inaugurate the playroom upstairs from the stop. Dad was "politely" asked not to run any noisy machines during that event.  Monday we had a long afternoon invite with some friends. But today I had most of the afternoon to play in the shop.

The first task was to turn the top caps, after which I drilled and tapped both them and the block. I also tapped the mounting holes for the upper plate, allowing a test fit:






I then made a pair of blanking plates and tapped the mounting holes in the block. The DRO did manage to get the holes in all three parts to line up, so I was able to screw them all together. The only "glitch" is that one of the valve holes is slightly obstructed by the plate, but taking apporx .01" off that end should solve that.

Since I had the top section chunks lashed together, I was interested to see how it would look connected to the bottom. I'm going to make the columns during the summer CNC lathe class, so I decided to quickly make a set of plain columns from some 3/4" Al round I had previously scavenged. I had only enough time to finish two of them:






The soda can is included as a size reference.

Now it's time to get cranking on the crankshaft.


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## Maryak (May 27, 2009)

Kvom,

Very nice it's really starting to look like an engine. :bow: :bow:

Best Regards
Bob


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## kvom (May 27, 2009)

I finished the other two temporary columns this afternoon, and started on getting the sliding pieces to fit. First up were the bearings. Here's my alignment/lapping setup:






I ran it about a half hour with the toothpaste, cleaned it up and oiled it. The drill rod turns pretty smoothly now. I then did a bot of catchup by drilling and tapping the holes for the setscrews on the eccentrics. Next I lapped the bores of the crossheads in the same manner as the bearings. I discovered that one of my crosshead guide bars was slightly bent, so that's a job for another day.


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## kvom (May 31, 2009)

I had the afternoon to play in the shop, and worked on getting the crankshaft and its attachments done.






The assembly does turn without binding, although I don't have the bearing blocks clamped down really tight. I discovered that I need to enlarge the central baseplate opening slightly, probably .01", as one of the crankwebs is hitting the corner.

If I can get the conrods finished next I can connect up the crossheads and get them lapped in.


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## kvom (Jun 2, 2009)

Today I narrowed the heads of the conrods to fit the cross heads. I removed the top section and attached the crosshead guides to check for fit. The crossheads went on fairly cleanly, even without any extra "wiggle room" with the guide mounting screws. I did find that one of the guide rods was slightly bent, so I needed to make a replacement. I found that my rear temporary columns were too thick and interfered with the crossheads; so I needed to turn them down to clear.

Then I made one of the link pins to connect the conrod to the crosshead and put it together with the crankshaft, as shown here:






I am able to turn the cranksahft by hand and move the crosshead up and down, albeit somewhat stiffly. The conrod is still a bit wide and rubs the crankweb. Since I plan to taper the conrods this issue will go away.

Progress might be slow the next week as we will have houseguests.


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## shred (Jun 2, 2009)

As I remember, my crossheads worked ok until I assembled everything.. then I had to enlarge the mounting holes a little , so don't be afraid to do that if needed.


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## kvom (Jun 3, 2009)

Only had a couple of hours or less today. Turned the conrods between centers. I couldn't taper the entire shaft but got reasonably close:






Here's the setup:


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## kvom (Jun 7, 2009)

Better progress today in a short 90 minute session. I finished the glands for the valves, where previously I had made the gland and screw. Tonight I drilled and reamed the through hole for the valve stem as well as the two mounting holes. I was apprehensive about this step, but all went smoothly.






Although I didn't see anything in the plan about where to drill the mounting holes in the steam chest, John's photo shows them fore and aft. That's a job for another day, as well as lapping the valves into both the glands and the valve bores.


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## shred (Jun 7, 2009)

kvom  said:
			
		

> Although I didn't see anything in the plan about where to drill the mounting holes in the steam chest, John's photo shows them fore and aft. That's a job for another day, as well as lapping the valves into both the glands and the valve bores.


FWIW, I put the gland mounting holes in the orientation you have them in the photo. Done like that the holes will likely intercept the cross-holes for the valve block mounting, somewhat limiting the length of screw you can use, but it's not a big deal and it makes tapping easy with a 'gun'-type tap. Put 'em the other way and you may hit the steam inlet for the bottom of the cylinders, which I think would be worse.


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## kvom (Jun 11, 2009)

Today I milled the steam slots that connect the steam chest holes to the block holes. As mentioned in a previous post, it's possible to mill the slots in the block rather than the steam chests, and that's what I did. I used a 1/8" endmill cutting .11" deep.

I also made V3 of the pistons, this time threaded 10-24 for a stronger joint with the piston rods. The other end of the rods are 8-32 for connecting to the crossheads.






I managed a better fit on the pistons by taking tiny cuts on the lathe. One is already a tight slip fit on one cylinder; the other will require some more polishing. If I can get the pistons lapped I'll drill and mount the glands next.


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## shred (Jun 11, 2009)

Lookin good.. that block's growing holes by the day..


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## Maryak (Jun 11, 2009)

kvom,

I'm with Shred. Looking good. :bow: :bow:

Best Regards
Bob


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## kvom (Jun 12, 2009)

The only holes left to do in the block are for the steam glands for the pistons. I'll be glad when that's done as I don't have any material for a redo if I were to screw up.


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## kustomkb (Jun 12, 2009)

Looks real nice, going to be a beauty!


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## kvom (Jun 12, 2009)

I lapped the pistons so that I have a good sliding fit. I tapped the hole in the crossheads to accept the piston rods, and assembled the block and top plate to the bottom with one piston in its cylinder and the rod screwed into the crosshead. Although the mechanism operates fairly well (able to turn the crank by hand), there is an obvious issue: at TDC the piston protrudes through the top of the block.  ???

Since I had made the piston rod to the same scale as the rest of the parts, I am wondering if the 75mm on the drawing is correct. I checked the rest of the critical elements (stroke, length of conrod, height of columns, height of bearing blocks), and all seem correct. Doing some measurement of the piston postions I concluded that my piston rod is .45" too long, corresponding to 7.5mm off the plan's size.


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## kvom (Jun 13, 2009)

One step forward, two steps back.  :'(






I drilled the gland mounting holes and the block, as can be seen. Why the missing screw? Because there's a broken 5-40 tap in the hole.  :wall: So I will get a chance to try to dissolve it out a bit later. In the meantime it's not holding up progress.

After screwing down the glands my piston rod/piston assembly wouldn't go in; turns out the thread on the piston iend of the rod is slightly tilted, so scrap one piston rod. In addition, I had a bright idea that instead of cutting an external 8-32 thread on the crosshead end of the rod, I would drill and tap an 8-32 hole in the end and use a bit of 8-32 screw for the connection. In theory it should work, but the two I tried ended up with the hole slightly off center. At least the threads were straight. I still have enough 3/16 drill rod for 4 or 5 more tries at good piston rods.

It's getting "tricky" to figure the sequence for putting everything together. I believe the best approach to connect the bottom and top sections is to have the crossheads as part of the top, so that you need only bolt the crosshead to the conrod and the top plate to the columns (haven't made the eccentric linkages yet).


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## kvom (Jun 14, 2009)

Here's my results for the day's activities. Rather than worry about getting straight threads on both the piston and piston rod using my crappy dies, I decided to experiment by turning the piston and rod from one piece. The first one worked well so I made the second. ;D

Because there are fairly tight fits on both the cylinder bore and glands, any deviation would tend to bind. By turning them together, they're concentric and (hopefully) straight. I still have to thread the ends for the cross heads, but any issue there can be adjusted by enlarging the mounting holes for the crosshead guide rods to allow "wiggle room".






In any case, I have a good sliding fit on one cylinder, while the other needs a small amount of lapping.


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## ariz (Jun 16, 2009)

you are making a great work kvom, well documented and with many interesting points :bow:

I'm anxious to see the engine completed and running!


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## kvom (Jun 16, 2009)

Today I started on the steam control block, which is the last component needing to be machined and the last assembly that can be completed until I am able to silver solder pieces together. Here's the block and spool, along with the elements of the eccentric linkage completed since the last photo:







I made several errors in machining the block, none of which I think (hope) will require remaking it. 

The first issue was in drilling the mounting holes for the flanges. I was using the vise stop to center all of the holes on the edges, and apparently a piece of swarf or something got between the block and the vise jaw, causing these holes to be slightly off center. To work around this, I will need to offset the mounting holes in the two flanges, but this seems reasonably easy to do.

The second issue was in the size of the 4 steam holes. I just scaled these up from the 4mm plan spec, which means I drilled them 15/64. I should have realized that I would be soldering 1/4" tube into these holes. Since I machined the block out of 2" round stock, the block is slightly smaller than the plan scale would require (1.4" each side vs. 1.47"). This means that the holes are closer to the edge, and enlarging them would make them even closer. However, it appears that I can enlarge the holes to 1/4" while keeping enough material between the hole and the edge.

Finally, I made the center hole overlarge. I entended to drill it to 1/2" and then bore to .59". To save time I drilled the hole using a 1/2" endmill. At least the shank was 1/2" but the flutes made it a 5/8" endmill. So after boring, the hole ended up with a diameter of .645". This can seemingly be handled by making the spool larger to fit, and that's what I did. I also made the spool shaft slightly oversize at 1/4" as I need to find an o-ring with a matching ID. Once I get the O-ring the front and back caps can be machined.


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## kvom (Jun 17, 2009)

I had a full afternoon in the shop making the front and back plates for the steam control. It took a lot longer than I expected as I had to turn both pieces down from 2" brass round, and I wanted to keep the waste of material to a minimum. In addition, the boss on both is a close fit to the block, so some attention and repeated measurements took time. I had located a 1/4" ID by 3/8" byt 1/16" O-ring at the local hardware store this morning, so I had what I needed.

Here's the assembly:






I didn't have any 6-32 SHCS so had to use these for the trial fitting. I had been thinking of using stud and nuts here, but standard 6-32 nuts are too large and inerfere with the shaft.

The rear cap turned out to be a press fit to the block, so after screwing it in tio align the holes I pressed it in with the arbor press. I don't see it coming out again. I realized at that point that this part is unnecessary if you have the ability to bore a blind hole in the block for the spool.

Once I could measure the depth of the hole and the size of the boss on the front cap I could mill the spool to length. I probably cut it too close as once the 4 pieces are fastened tightly together there's a lot of friction; I can turn the spool holding it with pliers, but not with finger pressure alone. I imagine there is friction between the end of the spool and the bottom cap as well as the sides and the o-ring pressing against the front cap. Once I make a handle I'll be able to assess if it's too tight.

Here's the parts disassembled. I still need to mill the slots, pending some thoughts on other dimensions.






On the soldering front I located local sources for both firebrick and citric acid, so tomorrow I should have everything needed to get started. The first joints to be attempted will likely be the eccentric straps to the linkage blocks.


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## shred (Jun 18, 2009)

Cool.. I've been sidelined making the spool and control block ends for a while now. That's looking nice.


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## ariz (Jun 19, 2009)

very nice, and surely efficient, steam control
well done kvom!!!


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## Maryak (Jun 19, 2009)

kvom,

Very nice :bow:

Best Regards
Bob


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## kvom (Jun 21, 2009)

I finally got back in the shop this afternoon. The first order of business was to finish up and test something that a lot of people here have made: a diestock for the lathe:






The small part is 1" CRS drilled and reamed .5" and turned down to .65", which is the largest diameter the lathe chuck can clamp.

The larger part started as 1-3/8" aluminum round, bored 1" x .4" deep for the die, with the opposite end turned to .5" to fit the other part. Handles are 3/16" drillrod, and screws are 6-32 (I'll cut them down some later).

I also made a second try at silver soldering, and this time it seemed to go a lot better. Here's the joint in a piece of scrap after 1 hour or so in the pickle:






This time I used a very little flux and chamfered the hole manually with a countersink.


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## ariz (Jun 23, 2009)

it's perfect kvom, but...

all my tests go always well, perfect like your piece
then, when it's time to solder seriously, lot of problems from everything :big:


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## kvom (Jun 23, 2009)

Past few days in the shop have been dedicated to working on the Jeep, after breaking a control arm bolt on Saturday that also resulted in a busted shock absorber.  

That said, this morning I took a little while off wrenching to silver solder the eccentric straps. This is the result after 2 hours of pickle soak:






I used 3/16" drill rod turned down to .150" on each end.


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## kvom (Jun 25, 2009)

Crawling under the Jeep replacing shocks left not much time for any engine building, esp. as I have a sore back as a reult. That said, I spent a couple of hours making some temporary air inlets, copied from shred:






I also had to re-do soldering one of the eccentric straps. Seems as if the solder did not go where it was supposed to.

Seems as if the only machining needed to be able to try out the engine under air is to fabricate the pins for the eccentric joint and thread the piston rods for connecting to the crosshead, and then I can try to put it together and do the "tuning". If I can get it to run then I'll need to make some feet and try to figure out if I'm going to make the bent copper lines like shred or make the straight flanges. I'd like to make gbritnell's tube bender, so I will investigate that option soon.


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## shred (Jun 25, 2009)

Good plan making them to use flexible hose. I thought I'd be all clever and soft-solder mine to the copper pipe in-situ and ended up soft-soldering one of the inlets to the block.  :


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## kvom (Jun 30, 2009)

With all the working pieces fabricated, I wanted to put it all together for a trial fit. Here's the result:






It's not quite ready to run yet, as it's still too stiff to turn by hand. The main culprit is the right hand piston rod, which binds in the gland.  I think I will progressively test each eccentric and each piston separately to try to get them loose enough so that the tuning process can be done. The bottom end (crankshaft) does turn by hand fairly easily, and the valves and one piston slide freely when not connected, so hopefully I can get it to run quite soon.


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## ariz (Jul 1, 2009)

you have almost finished kvom, compliments, very nice engine :bow: :bow: :bow:

surely you'll achieve your goal and the engine is going to run soon

we are waiting for see it


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## zeeprogrammer (Jul 1, 2009)

Looks great.
Really appreciate your comments on getting the engine ready to run.
I'm learning a lot here.


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## kvom (Jul 13, 2009)

Aside from making a rough set of support bars from 1/2" square brass bar to replace the 4 screw "feet", I've been spending what shop time I have in doing the fiddly bits to get it ready to run.

With some advice from others I went back to square 1 to ensure that the crank assembly is straight. After verying the bearing blocks on the durface table, I re-deburred the mounting holes and opeining in the base plate. Upon reassembly I can now turn the entire crank and components with finger pressure. Previously I was getting some binding. There are lots of parts that slide together on this engine, so getting all the sticky parts to work together can be tedious.

I will ensure that the crank is parallel to the centerline by mounting the base in the mill vise and using an edge finder at each end.

My summer CNC class starts up again tonight, and I hope to use the Haas to turn 4 "bling" columns.  I would also like to make some dies to use in making gbritnell's tubing bender.


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## kvom (Jul 16, 2009)

My first try at running failed.  ???

I went through the chapter on tuning, and as far as I can tell the various components are set as indicated. I tried to adjust the bottom with the engine assembled, but found that tightening the crank webs sufficiently was a problem. Having a set of T-handle allen wrenches would have been an advantage. So I removed the top to adjust the bottom. Of course, when I put it back together things were stickly again. Eventually, as usual, the issue is traced to the crosshead guide rods, which seem to have to be "just so". I decided to ignore the problem for the time being and removed one of the rods from each crosshead.

My bits of threaded rod connecting the valves to the eccentrics were too long, so I had to reduce the lengths to get the valves set in the indicated positions. Once that was done I screwed on the top caps and replaced the blanking plates. 

Then I discovered that while the input barb for the engine is for 1/8" tubing, my regulator takes 1/4". Sp it was off to the local hardware looking for a reducer with different size barbs on each end. No luck there, so I came home intending to make one on the lathe. While rummaging in some storage drawers, I found a Schrader valve with 1/4" NP threads, so I decided to put that as the engine input and hook up the regulator used for filling tires.  :

Since it takes two hands to maneuver the hose, I couldn't see everywhere the air was escaping (engine didn't turn whatsoever). I did see oil all over one of the joints between the block and the steam chest. I need to enlarge the holes in the blanking plates and shorten a couple of the screws to get a tighter seal. I'll also make a double barb connector so that I can run the air hands-free and try to see where the leaks are.

Any other ideas gratefully solicited.


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## shred (Jul 16, 2009)

A little leaking isn't fatal by any means. With a decent compressor pushing a good volume of air in at 50+ PSI, leaks won't matter (make sure air is getting to the right places at least-- a leak could be the only exit if a passage is blocked, but other than that, leaks can be dealt with later). I still haven't put sealer in mine and it leaks quite a bit as well as having imperfect valve timing.

I needed a good strong hex key and a degreasing of the crankshaft rods to make it all stay put. The crank takes a lot less force when the engine is actually running, so don't sweat it if it moves a little when you lean on it hard by hand (it's just annoying and frustrating, is all )

Binding and tight spots are what you need to chase down and get rid of. 

I blamed the crossheads for a lot of things that were really glands and packnuts binding and slightly off-round valve spools (those are tricky-- with the engine apart everything looks and feels good.. assemble and rotate a little timing it in and now they're dragging..)

Getting the timing 180 degrees out manifests itself as the engine kicking over a little when you turn it over by hand with air applied, but not all the way. Proper eccentric timing is the fat part of the crank webs at the same side of the engine when their respective eccentric is all the way lifted up (obviously the two cranks are still 90 degrees apart, so they aren't both on the same side at the exact same time, it's the relationship of crankweb-to-eccentric that's key). 

Keep at it as time allows-- tune one part at a time, don't be afraid to take stuff apart and work on the subassemblies one at a time and you'll get there. It took me quite a while to get mine to run the first time as well. Oh yeah, if you're using the temporary intakes, try switching them to the other set of ports every so often-- sometimes it really prefers to run one direction than the other.

Here's a copy of the MM post for completeness here:



			
				Shred said:
			
		

> Since I just went through and re-turned my engine the other night, here's how I went about it-- Starting with an assembled engine that doesn't want to run, even if timed correctly (check this! I messed it up for days of frustration)
> 
> 1 - Separate the top and bottom halves. Pull the piston and valve pins and undo the tops of the columns. Now you have the crank half separate from the block half .
> 2 - While you are separating, check the con-rods and eccentric joints are free-- I found that bead-blasting peened one enough to rub. Fix those.
> ...


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## zeeprogrammer (Jul 16, 2009)

kvom  said:
			
		

> My first try at running failed.



No, no failure yet. This is first run at adjusting and tuning. So far you've only had success. Looking forward to the video of it running.


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## kvom (Jul 17, 2009)

Shred,

Thanks for the feedback. As soon as I make the air connector and free up my hands, the first thing I want to do is remove the top caps to ensure that air is entering the cylinder. Since the crank does turn with finger pressure, I would expect that a pressurized cylinder would at least cause th pistons to move.

It will work eventually I'm sure.


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## kvom (Jul 21, 2009)

[ame]http://www.youtube.com/watch?v=GlX9dvjIcgA[/ame]

 ;D

I haven't been posting my birthing pains here, but it has taken a fair number of disassemblies and fiddling to get it to run longer than a few seconds. Today was the magic hour.

Run in the video is with 1 guide rod per crosshead at 40 psi. The engine still needs to have 1 piston just past TDC to self-start, but once started it will run for minutes on end. Perhaps I need to do the 10 hr. run in that Bogs did. The only change I made since last night was adjustting the #2 valve a few degrees. It then ran for 4-5 minutes until stopping. 

I then discovered that the vibrations had loosened the grub/set screws on the #1 valve allowing the timing to go off. On the second long run the same thing happened on the #2 valve screw. I am thinking that the #2 eccentric can be loctited to the shaft without causing any problems. For the #1 valve I might need a deeper notch in the shaft or else a hole drilled into the notch.

I'm guessing the reason the engine won't self-start in all positions is that there is still a fair amount of static friction to overcome, and that a half-stroke of the piston doesn't generate enough momentum. It might be interesting to mount a heavy metal disc on the end of the shaft. One area of friction that I'm aware of is between the eccentric clevis and fork. I think a bit of filing on each will help the next time I do a disassembly.

Another thing to try is moving the air to the lower inlets to see how it runs in reverse.


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## Maryak (Jul 21, 2009)

kvom,

Congratulations on a successful build. :bow: :bow: :bow:

Best Regards
Bob


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## Groewrs (Jul 21, 2009)

Good work, kvom 

It must have been frustrating, but it has to be worth it in the end, hey?!

What's next? ;D

Gordon


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## kvom (Jul 21, 2009)

Now I need to finish the reversing spool valve, but that will require making George's tubing bender. I'm also making new columns on the CNC lathe at school; hopefully they will be done next week.

Then there will be a lot of bling polishing to do.


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## ksouers (Jul 21, 2009)

Congratulations kvom!

Looks like a really nice runner :bow:


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## rake60 (Jul 21, 2009)

Congratulations Kirk!

Beautiful build!!! Thm:

Rick


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## zeeprogrammer (Jul 21, 2009)

Nice kvom.
Glad to see the video.
Always inspirational to see success.


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## shred (Jul 21, 2009)

Sweet!

The eccentrics on mine pretty much stay put on the shaft flats with just a setscrew, but there's probably not much harm in sticking them there a little more permanently or loctiting the setscrew at least.


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## lugnut (Jul 21, 2009)

:bow: :bow: :bow: I like it, I like it!
Mel


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## ozzie46 (Jul 22, 2009)

I knew you would get it! Hurray. woohoo1 woohoo1 woohoo1

 Ron


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## ariz (Jul 22, 2009)

congrats kvom, very nice running engine :bow: :bow: :bow:

perhaps it isn't many blingy at first glance, but it is a quite difficult work that requires many skills and work and patience

very well done!!!


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## kustomkb (Jul 22, 2009)

Congratulations!! Looks great and sounds real smooth.

Nicely done.

Kevin.


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## kvom (Jul 22, 2009)

There's still work to do on this, especially the control/reverse valve. I need to make a tube bender for this. I'm also making some nicer columns at school on the Haas CNC lathe.

Today, on advice from Bogs, I injected motor oil into the air lines as an aid in "bedding" the engine. I ran it for an hour, with many intermittent stops. Since it vibrates quite a bit, I had various fasteners loosening up. I needed to tighten up the piston gland nuts with a wrench. I also found that the screws holding one of the steam chests had gotten a bit loose allowing it to tilt slightly and pinching the valve stem.

At the end of the hour it would run a bit more smoothly and at 30 PSI. It still doesn't self-start unless one of the pistons is just past TDC. I notices at the end that the jam nuts on the valves had worked loose as well, so I think it's likely that the valve has adjusted itself further out.

I'll keep working on it. Since the compressor runs full time when the engine is working an hour at a time is about all I can stand.


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## kvom (Aug 6, 2009)

I finally was able to get the columns made on the CNC lathe at school. 







On the left is a temporary column, followed by one that's been tapped and the others I need to drill and tap. To get the same profile manually would have required grinding some form tools, plus cutting the taper either with the TA or the compound. This was my second project for actually making a part, and the first that I designed myself. There were two g-code programs:

The raw material was 5.5" lengths of 1" 6061 rod. For the first program, the rods are clamped in a 1" collet with 2" exposed. This program faces the rod and turns the 1st .5" down to a diameter of .49". It then centerdrills to form a 60 degree chamfer, then drills 3/4" deep with a #36 drill for later tapping 6-32.

For the second program, the pieces are clamped with 4.5" exposed. A live center is used in the chamfer created in step 1. The program turns the profile using a 3mm round tool, then parts off the column at a length of 4.16", a few thousands overlength.

To finish for mounting, I chucked the column on the lathe using a rubberflex collet, with the bottom exposed. I could then face the bottom and drill and tap for the 6-32 mounting screw. I then tapped the top end at the workbench. Once I do all 4 I'll use the height gauge to measure each one, and then face so that all 4 are the same length to with .001.


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## Maryak (Aug 6, 2009)

kvom,

Great columns. :bow:

Best Regards
Bob


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## kvom (Aug 28, 2009)

Getting a little more done on this. I drilled/tapped/mounted the new columns, and also made a pair of flanges for the input/exhaust pipes. I decided to make 1-piece flanges rather than separate, and I think that will make the fitting a bit easier when I finally get the little tube bender finished and can attach the valve assembly.


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## kvom (Sep 28, 2009)

Here's a photo log of progress on the engine.

First, the mini tube bender for making the 90 degree bends in 1/4" tubing:






A trial fit once the tubes are trimmed:






The side flanges with some temporary tubes for fit:






The top/bottom plugs soldered:






And them milled flush:






The tubes soldered into the valve body:






The handle for the valve:






Valve after soldering tubes to the flanges:






And the problem gaps where the tubes enter the flanges:


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## Kermit (Sep 28, 2009)

Could it be repaired by flairing the pipe internally?


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## ozzie46 (Sep 29, 2009)

Could you not just add more flux, another ring of solder and resolder? Keep the heat on the flanges and you should be ok. IMHO.

 Just soldered up my control block. Everything went well even though I missed the part where Bogs said to use 2 rings of solder on the joints. I used 1 ring, still got nice fillets.

 Am taking pics and will post them at a later date. 

A bit off topic but... Trying to get shop ready for new addition http://www.grizzly.com/products/10-x-22-Bench-Top-Metal-Lathe/G0602

 Really like your tubing bender. Thm: Thm: Thm:


 Ron


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## zeeprogrammer (Sep 29, 2009)

Very nice kvom.
This is an interesting thread.


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## kvom (Sep 29, 2009)

> Really like your tubing bender.


George Britnell contributed the plans, so credit to him.


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## shred (Sep 29, 2009)

Looking good. A pickle soak and re-solder with another ring of solder should fix up those tube joints in no time.


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## ariz (Sep 29, 2009)

I agree with shred, the position of tubes and flange is favorable for a new try

this engine is always intriguing, good works on those tubes and flanges anyway kvom :bow:


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## kvom (Jan 20, 2010)

I _finally_ got around to resoldering the flanges and finishing the reversing valve. Only took 4 months since the last post.  

But here is it, ready for disassembly and some polish. I am going to remake the blanking plates.


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## 4156df (Jan 20, 2010)

Great looking engine! Glad to see that re-soldering works. I've been wondering.
Dennis


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## kvom (Jan 20, 2010)

After several months of 2-56 screws on the Halo, those 5-40 screws seem HUGE.  ;D


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## shred (Jan 20, 2010)

#5-40?? Oh yeah, you made it 1.5X, right? That'll be a pretty good handful of engine.

Looks good. I like the reversing arm. 

We wants video!


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