http://www.thingiverse.com/thing:126778 http://airtripper.com/1676/3d-printer-extruder-filament-drive-gear-review-benchmark/ A few adjustments have been made to the design to make the extruder easier to set-up and use. Also, tweaks have been made to get a much cleaner 3D Print. http://airtripper.com/1071/airtrippers-bowden-extruder-v3-updated-design/ Designed to fit NEMA 17 Stepper Motors, and can accept the Raptor Universal Filament Drive Gear and other similar size drive gears. For 1.75mm filament only.STL File Content Detailsairtripper-extruder-v3.stl Main body only airtripper-extruder-v3_e_a.stl Extruder and axle airtripper-extruder-v3_i_s.stl Idler and Strut airtripper-extruder-v3-all.stl All parts included airtripper-extruder-v3-axle.stl Axle only airtripper-extruder-v3-idler.stl Idler only airtripper-extruder-v3-idler2.stl idler with flange only airtripper-extruder-v3-strut.stl strut onlyFull parts list and assembly instructions are here: http://airtripper.com/1071/airtrippers-bowden-extruder-v3-updated-design/