Acme Threaded C-Clamp

This is an attempt at an Acme threaded C-Clamp. I do not know how well the overhang of the Acme threads will work.

Updates

* v1 Acme thread printed perfectly at 0.25mm
* Deleted M12 version
* v2 is more like a real clamp including swivel pad
* New v2 swivel pad is has looser tolerences, it may work now. (Fingers crossed.)