This is a simple clamp for Arca-style mounts. It's 3D-printed plastic, so I wouldn't rely on it for expensive or heavy camera setups, but for just having a quick way to use Arca-style mounts to hold a smart phone or other small devices it seems to do the trick.
It has a 1/4"-20 threaded hole for mounting to a standard camera tripod, and uses an M5x16 thumb screw for the clamping operation. (Many GoPro-style thumbscrews work very well for this.)
At some point I might also add a 3-D printed thumbscrew to the model so a complete unit can be printed, but so far I've had plenty of machined screws so have been sticking with that.
Printed in PETG with a 0.2mm layer height, 10% infill, and 3 perimeter walls. For a stronger mount I suggest increasing the number of perimeter walls and/or the infill.
No supports are needed.
Use a M5x16 thumbscrew to attach the clamp to the base of the mount and tighten as needed.
The author hasn't provided the model origin yet.