About this 3D model

As I was moving from a 3mm hot end to a 1.75mm hot end I decided to build a belt drive version at the same time after I saw http://www.thingiverse.com/thing:339928 It also uses MR128 bearings as they OD is only 12mm vs 22mm (ID is still 8mm) just to get the size/weight down. 5-Oct-2014 Seem to be having issues with jamming so added a filament guide to go between the hobbed bolt and the hole in the extruder to eliminate any bending on the way in. It prints a little bit bigger so it can be filed to fit. 18-Oct-2014 Added the 30mm fan mount for filament cooling