Making the crank arms

(PLEASE NOTE - THIS ORIGINAL POST ULTIMATELY PROVED TO BE A FAILED ATTEMPT. I'VE CORRECTED THE PROBLEM BY USING STEEL CRANK ARMS INSTEAD OF ALUMINUM - SEE MY FEB. 1, 2013 POST)

I had a little bit of time yesterday, so I gathered up my materials for the crankshaft, including two small bars of aluminum that I'll use as the crank offset arms. My plan is to connect the arms to the shaft with loctite and spring pins.

I started off by cutting one of my two aluminum bars in half with a dremel cutoff wheel, so I would have three pieces total. I then held these together with some strips of gaffer's tape and marked the stack for drilling.

The gaffer's tape keeps the stack aligned and also reduces scarring by the clamps I used to secure the stack to the drill press platform.

Here's the stack drilled for the shaft and the spring pins.

Next I cut off a couple of small pieces of aluminum rod to act as alignment pins and retaped the stack in preparation for cutting on the scroll saw.

 And here are all three pieces, cut and rounded/sanded with the beltsander a.k.a "Ol' Bitey".

I used a 20 TPI scrollsaw blade on a low speed setting, lubricating the blade with WD-40 frequently. After the first crosscut of the stack, the blade was fairly dull, so I did the second cross cut with the stack sitting on top of a half-inch wood scrap in order to take advantage of the sharp blade teeth higher up on the blade. For sanding/shaping, I used a 100 grit belt on the beltsander and held the stack with a pair of visegrip pliers during shaping/sanding. I did a finish sanding with my 200 grit sanding block and then wetsanded with a bit of 1000 grit paper.

(PLEASE NOTE - THIS ORIGINAL POST ULTIMATELY PROVED TO BE A FAILED ATTEMPT. I'VE CORRECTED THE PROBLEM BY USING STEEL CRANK ARMS INSTEAD OF ALUMINUM - SEE MY FEB. 1, 2013 POST)