Ron's Compact Extruder

This is not the extruder you're looking for. If you're looking for the extruder referenced in Josef Prusa's i3 design, see http://www.thingiverse.com/thing:24219

A direct drive extruder designed for use with a Minebea geared stepper motor, a Makerbot drive wheel, and a MakerGear GrooveMount (or similar) hot end.

All Electronics is out of the required motor - MPJA has a supply of them at a slightly higher price - http://www.mpja.com/prodinfo.asp?number=18840+MS

From the very beginning with my printer, I've been fighting clearance issues with the extruder, which has prompted me to attempt a long series of different extruder designs. I tried internal (ring) gears, a printed planetary gearbox, and a Legoâ„¢ (!!!) worm gear. None were completely satisfactory.

I was about to break down and spend $33 apiece (plus shipping) on gearbox motors from robotshop.com, when ezmobius linked a Minebea gearbox stepper in IRC which was selling for $6.50 + shipping (Many thanks, ezmobius).