We had some broken frames around the house which needed repair. I saw a similar clamping system and decided it would be an easy print.

This design works and I don't intend to update. If I was starting over, I would consider designing the knobs into some type of gear that I could drive with a drill since it takes a lot of turns with long threaded rod.

The printed parts are very simple, just print four of each piece. I used four pieces of 1/4"-20 threaded rod and 12 nuts. For the knobs, I heat up my capture nut and pull them into the piece. The nut internal to the corners is simply inserted.