Simple bowden extruder for geared Nema 17

Just another MK8 bowden extruder, this one is for a geared Nema17 stepper motor with the ratio 5.18:1. It was designed for a Rostock Mini Pro with minimal parts to print.

Parlist:
1 x Nema17 geared stepper
1 x MK8 drive gear
3 x M3 x 23mm screws
1 x M4 x 12mm screw
1 x Ball bearing 11mm x 4mm x 4mm
1 x Bowden tube fitting M5
1 x Strong spring ~ 25-30mm x 7mm (force at the bearing ~60N with my setup, needs to be reduced a bit)

Also included, a fixture to mount it at the smooth rod