This is a 3D printed clamp for clamping PCB boards with a max width of 72mm, and a max length of 150mm. I will design other clamps for wider boards. The clamps rotate 90 degrees as shown in pictures.

Supplies

Tools:

Soldering Iron
3D printer
M4 Allen Wrench

Materials:

3D printed parts (https://www.thingiverse.com/thing:6538677)
x6 M4 brass threaded inserts (These are a good buy. If you don't use those, make sure that your inserts have an O.D. of 5.4mm and are no longer than 4mm)
x2 M4 Hex Nut
x2 M4x12 Socket head cap screw
x4 M4x16 Socket head cap screw
x2 M4x10 Socket head cap screw

Step 1: Press in Inserts

Use a heated soldering iron to press in your inserts as shown in the above picture. After pressing, you may want to make sure that there is no plastic build up blocking the holes.

Step 2: Assemble the Base

Next, slide 2 M4 nuts into the slots of the Base and align the End Bracket's mounting holes over the nuts. Use the 2 M4x12 screws to fasten the End Bracket onto the Base, but don't tighten them all the way.

Step 3: Mount the Clamps

Now slide the Clamp Part 1 pieces onto the End Bracket and the Base. Use 2 M4x10 screws to lock them into position.

After that, align the Clamp Part 2 pieces with the holes for them on the Clamp Part 1 pieces and tighten enough to where you can slide a PCB board between them.