Sources are available at https://github.com/Lodran/differential_planetary_gearbox- Companion extruder soon to be available at http://www.youmagine.com/designs/pocket-extruder- Fits either a Nema 17 or Nema 14 motor.Four variations are provided:- gearbox_printed_sun_105.stl - Printed sun gear, 10mm (105ZZ) drive shaft bearing.- gearbox_printed_sun_115.stl - Printed sun gear, 11mm (115ZZ) drive shaft bearing.- gearbox_metal_sun_105.stl - Metal sun gear (See BOM), 10mm (105ZZ) drive shaft bearing.- gearbox_metal_sun_115.stl - Metal sun gear (See BOM), 11mm (115ZZ) drive shaft bearing.Note: Assembly is fairly configurable, so the BOM is more of a guideline than anything else.