I started off with idea that I wanted a removable altimeter bay. I didn't want to have 3 body couplers because I went with the anti zipper design which includes one already. I did some research on the web and found that it had been done before by Joe Coker. He had used a coupler that was cut in half with bulkhead plates glued into both with T-nuts on the side of those plates. This was exactly what I was looking for. I started off with a drawing of how it was going to be setup. I had a PML 3-inch parachute piston that I didn't use from a kit. I cut this in half. This gave me the two coupler tube pieces that I needed for the bay. Next I cut four 1/4 plywood bulk plates using a scroll saw to fit inside the tube coupler. After I sanded the plates and fit tested them, I glued two plates together and the other two plates together. Now I had my two bulk plates. After the epoxy dried for the bulk plates, I drilled three evenly spaced holes using a 1/8 inch drill bit on the outer edge in the middle for the T-nuts. To get the holes evenly spaced I just measured the outside circumference and divided by three. I did a quick conversion from decimal to inches, marked a paper template and marked the hole position on the bulk plates.
