Shop Notes - Steam Engine build, (almost) finishing the crank assembly

(Building a 1/4hp steam engine kit from castings.  Was a great xmas present, and I'd estimate I'm probably about halfway done.  I think I'll have it finished and ready for paint by the end of the month)

Last I left off finishing the crank wheels and attaching them to the rod+crank pin, now I figured I'd finally finish the base plate so the assembly could be mounted to the engine.

Not my proudest setup stuck to the side of the vise, but there's so much cast iron it's quite sturdy like this.  Also easy to adjust with some light hammer strikes to one side or the other.

Dialing in the centerpoint.  This isn't too critical but you want to be close enough so the shaft looks centered at both ends.

This whole setup was really hard to do.  All of the drills I had were either way too short or way too long, and I did not want to reposition and potentially lose concentricity between both shafts.

I ended up finishing the top part, then removing that cap and working on the lower cap.   That way when I reassemble everything should line up well.

Really pushing it for clearance though.  My longest 1/2in end mill was almost scraping the casting to get the last couple passes in.   Less than a few thou.

Once the lower piece was finished, the whole thing was flipped over and centered one last time to mill out the ends (so the crank wheels can fit in the center)

Boom!.  Fits almost perfect, with just a little tightness on the bearings that should wear in fairly quickly.

One thing I did flub was using the wrong 5/8" reamer on the crank wheels; it's supposed to be a press fit but instead the wheels can spin somewhat in the hole.    That's OK though because I prefer to use pins to keep the crank wheels locked to the shaft. 

I do still need to mill the 1/8in keyway for the shafts, but that's pretty boring so probably done off-camera.   I'm also waiting on an oversize reamer to finish up the valve body, hopefully will be in by Wednesday.

Definitely starting to look like an engine now🤭

Hope you enjoyed🤠