D-bot mk7 extruder

thingiverse

I use the bowden extras that come with the E3D V6, along with the MK6 filament drive gear instead of an MK8. For added torque on the filament, I recommend using a planetary gearbox stepper or finding and printing an add-on gearbox like myself. The MK8 gear provides more torque to the stepper motor, but may lose steps at high speeds when paired with the MK7. On the other hand, the MK7 offers better filament grip and less grinding due to its larger outer diameter, which increases surface area in contact with the filament.