These parts fit a 1 1/4" PVC Pipe and a wood cross bar. I used a trim piece that is L shaped to provide a front lip for the art. The "brace" piece gives you a small back lip to keep things from falling backwards. Everything prints without supports and is designed to give 2 points of support on each side of the wood cross beam which tightens up the square.
Screws that go through the PVC are 2.5" #10-32 machine screws.
2" #10-32 for the screws that go through the wood and the spacer+PVC2nd
1" #10-32 for the holes through the wood and PVC part.
I used wing nuts on all of it for easy assembly and break down.
If you do not have a drill press to drill all the way through both sides at once use the following method with a hand drill: To align them straight, place the PVC on the pipe at the height you want, drill your hole, place screw in hole to old it in place and lay flat side down at the edge of a table. Use the template laying on the flat side to mark the second hole at the same angle. Drill your hole, use a 1" screw to hold it, turn it over and mark the hole on the second side, drill and now you have a straight hole.