Extruder-X universal -1.75/3mm, direct drive extruder, Nema 17/23

Direct drive extruder equiped with the following features:
- simplicity - as little components as possible
- independent from drive gear diameter ( 7 - 11 mm)
- integrated motor and drive gear cooling
- support nema17 and nema23 motors
- independent from hotend type
- support for any filament diameter from 1.5-3mm
- open design in open scad format
Optional vitamins:
1. Spring
- M4 Butterfly nut for spring: http://www.thingiverse.com/thing:108661
2. Hotend adapters: