X or Y axis belt clamp with tensioning ram

A derivative of the Y belt clamp.
Modified to allow variation of screw spacing, teeth facing in or out, diameter of ram, and a few other misc tweaks.
Unfortunately subsequently realised my X belt is too short to be able to use it, and I already have one on my Y belt, so not yet released in the wild...

EDIT: 11/6/13: Replaced SCAD file to correct error placing screw holes.