This is a large bench hold-down clamp with pivoting head. It is sized to use 3/8" bolts. I use it to hold test samples onto a vibration table for reliability testing but I'm sure there are lots of other uses for it.

I'm using PETG with 5 perimeters and 40% infill for mine and it's working well so far. Supports are required for the sides of the cups.

OpenSCAD files are included for those who want to play around with them.