The Craftmans Shop > Model Engineering

Side Valve i.c. engine from Bar stock

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Brian Rupnow:
And so it begins---Once I had the outsides of the block milled to size, I set it up in the 4 jaw chuck and drilled a hole all the way through, and reamed it to 7/16" diameter. I then proceeded to use a series of drills to go part way through the block, until I topped out a at my 1" Silver and Demmings drill. Then it was boring to the proper depth and diameter. That finished hole that goes all the way thru will eventually be reamed to 0.5" for a bushing, but since I want to "align-bore" all of the plates together to get the bores all in exact alignment, that 7/16" reamed hole will act as a set-up hole when I get to that point.

Brian Rupnow:
I just about got caught!!! I finished up the two main bores in the crankcase, and just as I was finishing the hole thru the top for the con rod and cylinder base, I began wondering if I had checked for side clearance on the rod where it comes thru the hole in the top of the crankcase. I opened up the 3D cad model to take a look, and it's a good thing I did. What I had forgotten was that the big end of the con rod actually extends beyond the crankshaft web/counterweight, and there would have been a big time interference. I had to set the crank case back up in the 4 jaw (I hate that) and relieve a center path all around to clear the con rod big end. I took a couple of pictures while things were still set up to try and show the additional path I had to create. The original bore I had put in would have cleared the crankshaft web/counterweights with .030" radial clearance, but not the con rod big end.

Stilldrillin:
Brian.
It's good to have afterthoughts. Before it's too late......  :palm:

Well spotted!  :thumbup:

David D

Brian Rupnow:
David--I will post a download to all of the drawings for this engine as .pdf files for  those who would like to build it. I used to post the drawings as I was building the parts, but experience has shown me that I "tweak" the drawings so much as I go along to show what actually is made in metal, that I would have to repost the same drawing 3 or even 4 times. This drives everyone a bit mad, and there is too much chance of people not saving the newest "revision" and making bad parts. I am always thrilled when people build one of my engines, but it is a much safer thing to wait until I have a running engine with all of the drawings up to date before I post the link.---Brian

Brian Rupnow:
Well, if you squint your eyes real hard, and look at it just the right way, it's beginning to look like an engine.At least all the big parts bolt together.---That's a good start.!!!---Brian

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