Saturday, January 12, 2019

Ankle Cylinder Holders


The final part of the ankle is the Ankle Cylinder Holder. This is a crescent shaped piece right below the cylinder.

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To make the part I started with a template made from the plans and then traced that on a piece of 3/4” MDF. I rough cut the curve on the bandsaw and then finished it on the drum sander. The shape the template provided wasn’t a perfect fit for my ankle so I needed to do a little more sanding to get the size and shape right. On the flat side of the part is a cove that the cylinder fits into. To make this I started by removing some of the material on the table saw. I set the rip fence so that the blade will be right in the middle of the part, and set the blade to the maximum depth of the cove. After making that cut I moved the fence over one blade width and lowered the blade and made another cut on each side of the first cut. To remove the rest of the material I wrapped sandpaper around a piece of the same pipe I used for the cylinder and sanded the cove to it’s final shape.

I believe I did the crescent cut first, but in hindsight it would probably be easier to make the cove first and the cut the crescent shape.

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To attach the part I used dowel pins just like I did on other ankle parts. I used the same method as the cylinders to mark the location of the dowels on the ankle, putting some paint on the end of the dowels and using that to mark the ankle.

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One of the problems with writing these blog posts so long after the work was actually done is that I have forgotten some things. I found this picture and wasn’t completely sure what I was doing here. These pieces are made from plywood, but the actual pieces I ended up using are from MDF. These are nailed together in pairs. I think I did this so that I could sand two at a time and get perfect matches. These were probably a first attempt at the part that I discarded.

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Sunday, January 6, 2019

Ankle Cylinder Mounting


For most of the leg parts I used dowels to mount them to the leg. This allowed me to temporarily assemble the legs without having to glue things on. I will eventually glue the parts on and the pins will help align the parts and give the connection some more strength.

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To mount the cylinder I started with an MDF block that fit tight into the back opening. Before attaching the block I drilled two holes for the pins. The exact location of the pins isn’t critical since I have an easy way to transfer the location to the leg. With the holes drilled I used epoxy to glue the block into the cylinder.

To transfer the location of the pins to the leg I put temporary dowels into the holes that were just long enough to stick out beyond the block. Next I put a generous drop of black model paint on the end of each dowel and before the paint dried, put the cylinder in position on the leg and then pushed it down to transfer the paint to the leg. This will leave marks where I drilled the holes. Finally I replaced the short temporary dowel with the full length ones.