No, I did not build them. I had a machinest friend do it in exchange for building some of his kits for him. He told me to tell everyone that he made them and then died!
Anyway, I designed them somewhat after my plinker jig. I found a few things about the plinker jig I didn't like and changed them. First off, square.. not round. The squeezer bars will not spin or rotate to give a slanted shop head. Plus, now that they are square, they can be quick change (no set screws needed)! Bigger support cup so more of the receiver is supported and you get no corner indentations from the small cup support.
The box jig was simple, but I had to modify it to make room for the other rivet heads. It works best when the receiver is flat on the bottom, the large screw holding it tight to the bottom. The underside head is supported by a cupped set screw so that holds the rivet from sliding away from the receiver as I begin to press the shop head.
Brick