Back to the crankshaft

Now that I've got the reservoir/bellows assembly fairly complete, I figured I'd better return to my work on the crankshaft, since my first attempt with it failed so miserably.

I originally attempted to make the crank arms out of aluminum, but those turned out to be too soft, and the holes for the shaft widened out enough to make the shaft wobbly and useless. So I repeated the machining process, this time from a solid piece of 1/2" x 1/4" steel bar. This time, to ensure a tight fit, I drilled the shaft holes with a "D" sized drill bit (0.246"), which is slightly undersized for the 1/4" shaft. The shaft wouldn't quite fit into the holes, so I drilled them a little on both sides with a 1/4" bit, leaving about 2 or 3 mm. in the center at the smaller "D" size bore. I then polished the steel up so it would look as shiny as the chrome plated shaft steel, using 220 then 1000 then 1500 grit wet sanding, and finishing them to a near mirror finish with some white rouge polishing compound and a felt wheel on the dremel tool.

I then hammered the shaft sections into the crank arms and got a super tight and square fit for all the pieces. Even though there was no lateral or axial movement, I decided to play it safe and drill completely through the arms and shafts and tap in some 3/32" spring pins. I put a drop of loctite in each of the spring pin holes before inserting the pins. I would have used loctite on the shafts ends, but they were in so tight that the loctite couldn't find a gap to penetrate.

Here are most of the part laids out. I haven't attached the single arm/short shaft/rod end to the end yet, as I'll likely wait until I have it installed through the wooden panels. I'll also wait until I've got the whole pressure box assembly built, so I can tell how much to trim off the end of the shaft where the crank would traditionally go, since I don't want that part of the shaft protruding from the case.