About this 3D model
This is a modification of the great work of yoyoek1´s "double Hobbed bolt bowden extruder :)" (https://www.thingiverse.com/thing:280215) with a different lever coming from the WormStruder of takigama (thank you as well http://www.thingiverse.com/thing:28126). I think this lever allows better access for cleaning the bolt. It shall work for 1.7 mm and 3 mm filament. A specific bowden-fixation is still missing. updated version: http://www.thingiverse.com/thing:515747