Monday, October 13, 2008

Ankle Tubes and Shoulder Update

Here are the little tube things that go on each side of the center ankle and on the outer ankles. It took a couple of tries to get them just right, and I am still not perfectly happy with them. But I think once they are painted they'll be fine. I cut 1 inch (inside diameter) pvc pipe to length. Then I cut little squares of 1/8" pvc sheet to glue to the ends. I glued those and let them sit for a few days. PVC cement gets a lot harder if you let it cure for a while. If you sand it too soon, it'll be more flexible and soft than the surrounding material and you'll sand it out of the joint and make a groove.

Once those were cured. I used the sander to round the square pieces down to match the round edge of the pipe. This wasn't a very reliable method for getting them to perfect circles. But I couldn't think of another method that would leave me with no seams.

The little channels that are cut into the circumference of these pipes are supposed to be .03 " wide or so. My table saw blade is .1 so that was too much. My bandsaw blade was just right. I figured out the depth of the channels and put a stop on the crosscutting slider on the bandsaw so that it would stop the piece just after the blade began to cut the pipe. Then I would carefully roll the pipe into the saw blade, keeping the slider still. So it cut a groove all the way around the pipe. This was a reliable and good method with good results. It just took 15 minutes to cut all four pieces and a spare. Then I cut the little hexagonal end caps for the tubes and glued them on. A little more sanding and these will be ready to go.

Here are a couple of pictures of the finished shoulders. I'm pretty happy with these. In an earlier post I detailed how I built up the plywood pattern for these that would guide the router roller bearing as I cut them. I cut all 16 or so pieces, and glued them all together in stacks to make these ribbed assemblies. Then I sanded the outside edges down to clean them up. I spend some time putting putty on the insides of the interior pockets, as you can see, and then routing those on the forms again to clean them up. This wasn't the perfect method. If i was doing these again, I wouldn't cut the interior pockets out at all when I was cutting the individual layers. I would wait until the whole assemblies were glued up and then I would drill a hole in the middle of the pockets, and then rout that out once and all at once. Make sense? That is, instead of routing these pockets out 16 times on each individual layer piece, I would glue them all together and rout them once. Then I'd get really clean aligned inside edges. And there wouldn't be the need for putty. But I think these will clean up for paint just fine. The three dowel holes will get filled later. And I think I'll put some dowels sticking down into the legs for attachments.

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