Sunday, June 18, 2006

Tested Shoulder Hub Template, Mounted Template to Arm

Not much at all got done today due to other commitments.

I tested my shoulder hub template on some 1/2" scrap plywood, the same kind that makes up the top layer of the legs that I will be cutting and routing. I'm glad I tested, because I found that my "final" template from yesterday made a hole in the plywood that was a bit too snug for the aluminum hub to fit through. I went to my next larger template, and found that when I used it on the plywood, the fit of the aluminum hub was nice and snug, so I'll be using that template.

Next, I spent a lot of time trying to locate exactly where on the left leg to locate the template. I did this repeatedly, by installing the horseshoe on the leg, drawing an outline of the partial circle that the inner part of the horseshoe forms, and then trying to center the template within the horseshoe's partial circle. A couple of times I thought I had it, and screwed the template down, only to discover it was slightly off. So I'd unscrew the template, rotate it slightly, and try again.

I tried a few different strategies for centering, including drawing concentric circles from a common centerpoint, but whenever I mounted the template, I'd find that I was off by maybe a millimeter. Finally, with the horseshoe mounted, I used a ballpoint pen to trace the outline of the partial inner circle. The line was offset a small distance from the edge of the horseshoe, and that provided the guidance I needed to center the template where it should be (I hope).

I still have to go through all this again with the right leg, and I need to jigsaw-out a rough cut on the legs before I can actually use the template. I'm going kind of slow here, because I really need to get this right, or the hub won't easily come out of the arm.

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