Ron's Compact Extruder, Mark III

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.

Version 3 simplifies the design a bit, and tweaks it to make a stronger print.

I left ulti_rcx_2.stl, along with the old sources here because I broke ultimaker support while redesigning it.

Version 2 addresses two issues I had with version 1.

1) Idler pressure was very touchy - as you increased pressure on the idler, it would put axia