Idea for air/steam engine

[PStechPaul]

While I figure out the "plumbing", I am working on the details of the flywheel assembly. There are two 3.5" 1/2" thick aluminum disks with crankpins on opposite sides and a synchronizing bar connecting the pins:
 

I am trying to use some 3/8" O-1 tool steel drill rod for the standoff shown in the upper right. It should be a press fit into the 3/8" hole in the synchronizer bar, but the hole is a little too large. I could remake the piece (actually I am trying to salvage the piece I made for the previous design), but I might be able to use a chisel to make some knurl marks on the surface to make it fit tightly enough. I might also use some Loc-Tite.
 
Another idea I had was to tap the holes for 1/8-27 NPT and make mating threads on the standoff. That would make a tight joint, but it may be difficult to get the right depth.
 
The turned-down section is made for a 6x13x5 mm ball bearing, and it then should be a tight fit into the flywheel, where it will be secured with a #8-32 SHCS. The ball bearing will be pressed into the connecting rods, so it will become a fixed assembly not designed to be disassembled, although it could be. I may be able to add a setscrew in the flywheel to keep the standoff from twisting once it has been assembled and adjusted. From my experience with the previous design, the alignment is rather critical. I really don't know how much torque will be exerted on the joints - hopefully not too much.
 
I have started to turn down one of the standoffs, and it seems a bit difficult to get a good finish with a HSS lathe bit. I may experiment a bit with regrinding the tool and trying higher speed. Any suggestions on machining O-1 steel? Or perhaps I should use another material? I have 416 SS, 360 brass, and 1045 steel rod.
 
Here is some information non machining tool steel:
http://www.simplytoolsteel.com/machining-tool-steel.html
http://buffaloprecision.com/data_sheets/DSO1TSbpp.pdf
http://en.wikipedia.org/wiki/Tool_steel

[PStechPaul]

I have finally made some more progress on this project. Over the last couple of days I made the connecting rods and rocker arms, with ball bearings pressed in. Here is the drawing for some of these parts:
 
 

 
And here are some pictures of the beast as it is so far. These are the "rockers" that transfer motion from the pistons to the connecting bars. I rounded the ends on my bench grinder. I made the hole for one of the bearings a bit too big, so I used a chisel to deform the edges of the hole so it would hold. It's a 16 mm bearing which is 0.629". I used a 5/8" step drill which apparently drilled a bit oversize. On the other hole I was able to drill part way from each end, leaving a little rim of metal the next size smaller. probably 9/16", and that made for a decent press fit. I think I need an adjustable reamer for each bearing size.
 

 

 
I know that the Garolite phenolic is an unusual material for an engine, but I have quite a few small pieces, so I used them. I think it adds a colorful touch:

 
Probably a rather unique flywheel design:

 
I am hoping to get this motor put together for Cabin Fever. It might not run, but at least I hope to have most of the parts made and assembled.

[PStechPaul]

Still trying to get this somewhat finished for Cabin Fever, and I put in some shop time, but I goofed. I'll blame it on the freezing cold in my shop that addled my brain, but I made the error when I did the drawing in the (relative) comfort of my house. I wanted to make a shaft for the ball bearing in the connecting bars, and press it into the rocker. I had used 8x16x5 ball bearings, so I made the shaft for that, but the connecting bars have 6x13x5. So I made the axles from 3/8" brass rod, which I turned down to just over 23/64" (0.359") to press into a drilled hole that size with a press fit. That part was OK, but after I had pressed one in, I saw that it was too big for the bearing, and there's no way to modify the piece that's already pressed in, and very difficult to rework the other piece. So here's the result of a couple hours of wasted effort:
 

 

 
At least I was able to see that pressing it in place worked OK. I used my milling vise.

[zeeprogrammer]

Hm. I'd been wondering what to do about some press jobs in my project.
I hadn't thought about using the vise.