A Small and Llight Gearbox for a Stepper Motor

I wanted to build a small and light gearbox for a stepper motor (used as excuse: for building a light extruder for a 3D printer - didn't trust the bowden setup, and the scavenged driver might not have enough torque for a direct drive - real cause: playing around with the lasercutter :-)

I decided to use POM (polyoxymethylen), since it's quite strong, self lubricant and you can cut it with a lasercutter... if you have a good ventilation: Burning POM produces formaldehyde, not the best product for your health. So using a CNC mill might be more healthy.

On the other hand, we have now a three stage filtering system especially for formaldhyde, and a just fine tuned laser cutter - perfect for fine teeth.

I used apart from the laser cutter:

- POM (i used three different thicknesses, 2,3 and 4mm to get a really small and light version, but using only one (4mm) thickness is also possible)

- 3* bearings 3mm inner diameter, 7mm outer diameter, 3mm height

- 1* bearing 5mm inner diameter, 10mm outer diameter, 4mm height

- 3* 3mm hexagon socket head screw 12mm long, with 12 washer and 3 nuts

- 1* 5mm hexagon socket head screw 30mm long (but trimmed down) and 3 nuts (small height)

- 2* 3mm hexgon socket head screw 40mm long with 2 washers

- NEMA17 stepper driver (5mm diameter axis)

- MK8 drivegear for 5mm axis