For this assignment we were given a random type of joint to 3D model in Rhino and then produce with the CNC in plywood. I received the E-clip locking joint.

Step 1: Measurements & Modelling

I did the measurements and modelling concurrently, so it's hard to separate these as two steps. I started with the small L shaped peg since its the only piece that doesn't rely on the measurements of another piece. Given that the router bit is 6.35mm and the plywood is 1.8cm, I decided to make it 56mm long, 18+18=36mm for the width of two boards put together and 20mm extra for the back "plug". I also made the dog bones 6.5x6.5mm rectangles which were then rounded out to 3.25mm radius semi-circles. Now that I had the peg width of 20x18mm I could do the two pieces that the peg slots into. I also filleted the edges that would stick out so that it would be better to hold once CNC-ed.

Step 2: CNC

I had a minor problem with the CNC print; the second piece in the first picture's slot is slightly off center. After checking my model again I think the problem was actually caused in the final step in Carbide Create/Motion, where I may have accidentally adjusted the outer cut independently of the inner cut, and since it was by just a bit I didn't notice until I assembled it. Otherwise everything else lined up just fine.