I went to a physics workshop many years ago. One of the workshop leaders brought these really cool versatile table clamps. They were similar to these. I wanted some, but they are pretty expensive. I never really thought about 3D printing my own until I saw this blog post by Mark Schober.
I thought about just printing Mark's clamps, but I wanted another project to help me learn Fusion 360. I used Mark's clamps as my inspiration. The major difference is that I wanted only 3D printed parts. I was curious if 3D printed screws would work. I made the threaded bits in OpenSCAD with Mike Mattala's NUT JOB. So far it seems to work well. However, it has yet to see student use.
Like Mark's, my version will accommodate up to 1/2" electrical conduit. It also works with smaller stock as well.
The main clamp was printed with 3 perimeters and 20% infill. I printed the screws with 100% infill.