Prusa i3 Rod-Mounted X Tensioner

__[2014-11-20] Try [Prusa i3 Add-On X Tensioner](http://www.thingiverse.com/thing:554719) instead!__

This is a simple adjustable belt tensioner that mounts on the top rod on the right end of the X gantry.

[See it in action...](http://www.youtube.com/watch?v=u8CJW0iWXlo)