Reprap Prusa i3 Z belt tensioner

I needed to tighten the z-axis drive belt of my Reprap, so I designed this little device for use with an 8x24x5mm radial bearing.

The top and the bottom have holes for M3 nuts so you can screw it together.
(the size of the nut holes can be adjusted by changing $r_nuts in the .scad file)

**Caution: Work in progress!!!**
*This is not finished yet, so I'm still working on it.* ;-)