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Low Temperature Differential Stirling Engine: Crankshaft

The crankshaft is the axle that connects the flywheel hub to the piston assembly. It is made of two parts: a rectangular aluminum piece and a rod of steel fitted together.

First, I cut the rod off on the cutoff saw. Since the rod was so small (and steel!), I decided to grind it down to size on the grinding wheel. I sized the rectangular piece similarly.

Next, I drilled and tapped the holes in the rectangular piece. There are 3 holes: one in the center, for the steel rod to fit into; one on the front but off center to allow for the up and down motion of the displacer to move the shaft; and one to add counterwieghts to the latter.

Low Temperature Differential Stirling Engine: Flywheel Hub

The clear flywheel is mounted on the flywheel hub, which fits around one side of the crankshaft. It is made on the lathe from aluminum.

First, I drilled a hole in the aluminum to stabilize it with a live center while I cut it down:

I marked all the distances with my calipers and cutoff saw and then I cut the notch down.

I then began the process of hollowing out the center of the part, first gradually stepping up drill bit diameter (large enough to insert my lathe bit) then cut out the portion slowly with autofeed. …

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