A direct drive bowden extruder for 3mm

A direct drive bowden extruder for 3mm and a MK8 style hobbed pulley. The SketchUp Make is almost completely parametrizable, so it can be adjusted to fit other hobbed pulleys as well. I have used a 13x8mm, 5mm bore brass hobbed pulley, because it was easy to acquire in Germany (www.fabber-parts.de).
Parted used:
• 1x Nema 17 stepper motor
• 1x hobbed pulley 13x8mm, 5mm bore or similar
• 1x 5mm OD push-fit bowden connector (add another one for bowden inlet version)
• 1x 608 zz bearing