02 May 2012

Crankshafts!

Finally, I have a crankshaft! The 4th try is the charm, so I made two at the same time. I made two in case one of them got messed up. Well, they have both turned out (almost anyway, not quite done with the second but close).
 First I marked out both parts. This is 1"x3/8" bar. Drill a hole then bandsaw (I love my new bandaw!) the slot. Each end is center drilled in three spots one for each shaft.
 I had to use my cutoff blade to reach into the slot and turn the crank pins. Not as bad since most of the material was cut out with the saw. Continue removing the unneeded material with the bandsaw.
 Finally ready to turn the main shaft. Both crank pins are at correct dimension and the webs are cleaned up on the inside surfaces.
Using bolts and soup can shims to keep the shaft from flexing too much I can turn down the main shaft to 1/4".

I put the one finished shaft into the rest of the engine and it is a perfect fit. Spins smooth and free. I'm still working out a little binding on one of the connecting rods, and the valve gear seems to be a little bit off. Last steps will be to cut the valving and paint.

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