I edited the STL file in blender to resize the filiment hole for 1.75mm filament. Everything else is unchanged. In theory, I probably need up update the filiment guide on the idler as well, but since I already printed out a 3mm version, I figured I would give it a try first. Follow all other notes and instructions from http://www.thingiverse.com/thing:291291, and just print this one instead of the one on that thing.