Building Rudy Kouhoupt's Fore and Aft Compound

[gerritv]

From The Shop Wisdonm of Rudy Kouhoupt Vol 1 book, I started this in Jan 2019 and promply a) ran into problems, b) got distracted with other things.

a) was due to inadvertently trying to use copper instead of brass for the bearing blocks. After endless problems cutting this material and breaking 2 taps I moved on for a while
b) I diverted to the world of electric clocks, specifically repairing a clock made by Lawrence Bateman based on a Froment escapement. This appeared in an article in ME, Issue V134, No 3359 (1968). The clock appears to be partly based on a series by JRL Orange in ME in 1966 although Lawrence made design changes. I am confident I had met Lawrence at TSME meetings in the early 1960's, my father used to take me along frequently.

I then got sucked further into that vortex by building a Synchonome from a 1960's casting. That clock is waiting better weather so that I can get into the garage to build the case. And of course I need to make some repeaters to spread around the house.

We left the engine in this state in January 2019:

[crueby]

Glad to see you back in the engine world. I've  gone down the clock path a few times too, both are fun!  Watching along on this one.   

[gerritv]

Subsequently I replaced my 'interesting' second op horizontal mill with an Atlas MF and more recently replaced that with a King KC20 (like a Grizzly G0704). Wanting to gain experience with the new mill I dusted off the project box for this engine.

New support rails (previous ones had misaligned holes for the bearing blocks) and from my much improved stash of brass, new bearing blocks.

The UPT came in handy as always when tapping, esp. M2. (I am using hardware from https://kingmicroschroeven.nl) and also follow the advice of my dad's friend Bill Huxhold that metric tooling is much less expensive and easier to buy (and now of course from AliExpress :-)

At this point it is ready to drill and bore for the crankshaft.

[Dave Otto]

Looks like you are off to a great renewed start, that is one that I had a desire to build many years ago but never got past collecting some materials.
Looking forward to seeing your progress.

Dave
 

[steamer]

Nice build!   Rudy was a nice guy.   He did a talk at NEME-s once.   I got the chance to meet him and I got his autograph,  Very interesting guy!

Dave

[gerritv]

thank you for the welcome  back to MEB, I wish there had been a clock section :-)

I took some time to 3D print a mount for the newly arrived ring light. It works very well although there is a shadow from the drill chuck. But overall much imporved lighting.

I puzzled for a while over how to best bore the crankshaft hole. Rudy mounted his to carriage of his lathe. that did not appeal due to the length of drill needed, and the likelihood of it wandering off its required path. So I stacked the 3 bearing blocks on a piece of sacrificial aluminum and clamped the sandwich in the vise. A piece of wire at the moveable jaw end helped ensure all 3 were indeed trapped.
5mm drill followed by 5/16 and then a bit larger got me a hole close enough to ream. I wanted to keep enough metal so that the reamer actually had some work to do, else it would have cut undersize.
Once mounted back on the rails a .375 drill rod lined up for a very smooth running crankshaft sample. Tomorrow I will make the 3 oil cups and then start on the crank webs.

Gerrit

[Kim]

There's always the 'oddball' sub-forum for clocks.  I'd have enjoyed seeing your clock work there!

But I'll enjoy following your RK engine build now!

Kim

[tghs]

looking great, I used RK's book quite a bit in building my compound navy engine, copied and enlarged (so it was easier to read) the section on tuning and timing.. RK's books have lots of great info...

[gerritv]

Made the oil cups so 1 of 10 groups of parts are done (barring finishing and polishing of course).

I cut the key way for flywheel, my first time doing this. I usually file/mill flats but this will result in a cleaner installation.

Next up some creative work holding to make the crank webs. 1"x .125" cold rolled, milled to .5" width and then clamped in the vise. This turned out very well, the holes are a close fit on the pins which should make for a pleasant silver soldering experience. Next up is making some filing buttons for the rounded ends.

So far doing this without DRO, just layout lines and a sharp pointer to locate, followed by dial counting.

[gerritv]

A question for those more experienced in making crankshafts. Rudy says to silver solder and while I think I might be proficient enough in that art form to pull it off I wonder if retaining compound and 2mm pins would do the job just as well.

The webs are bored and radiused. Bores are a very close fit on the crankshaft and crankpins.

gerrit

[crueby]

I've done several as built up with retaining compound and taper pins, worked out great. Have not tried straight pins, they would need to be a good close fit. Roll pins can work too.
 

[gerritv]

Thank you Chris. I just happen to have taper pins and the reamers.

gerrit

[Kim]

I've used Loktite and straight pins for a built-up crankshaft before.  Hasn't fallen apart yet.  And I'm sure it's had hours (maybe one at least?) of run time in it's hard life! 

The straight pins were a press fit and I added Loctite just for fun.

Kim

[gerritv]

With that encouragment I made some progress.

The first web was drilled, then glued and pinned. The second web was then aligned, spaced andd the crank pin glued in. Then the second web was drilled and pinned to the crank shaft. A bit fiddly in the end so for the next webs I will glue the first half into place, then drill and pin it. Followed by the second web and crank pin.
Part of the reason for the sequence change is to enable me to align the pin parallel with the crankshaft.
Once the webs are attached I will drill the crank pin ends and pin those as well.

gerrit

[gerritv]

Annnnd, we have a crankshaft. Glued (Weicon 306-38, similar to LocTite 638) and pinned.
It needs a bit of running in but overall very very pleased. I did knick one crank pin with the hacksaw while removing a crankshaft piece :-( but I expect it won't matter much in the end. I will smooth the edges of the cut. At worst it will retain oil.
I still need to pretty it up but for this stage of the build it is good to go.

That completes group 2 of 10 in the assemblies. Next up is the flywheel.

Gerrit