Gearbox and curtain cord teeth for NEMA17

This is a derivative work of the Herringbone Planetary Gear Bearing by Emmett Lalish.

DEPRECATION NOTICE: New model available here: https://www.printables.com/model/178044

Curtain cord configuration: 4mm diameter balls and 2mm of thread in between them.

If your curtain isn't compatible with this configuration, consider editing Curtain Gear.scad. For simplicity's sake I've only included the STL of the final product. You'll have to download all scad files into the same directory, and export all of them as STLs before invoking Joint Shaft-Mounted Assembly.scad.

Tolerance of the planetary gear is 0.15mm, the rest are designed at 0.1mm tolerance.

This also requires 6x M3/20mm screws (for fixing the herringbone planets) and a NEMA17 motor (I bought a MT-1703HS168A from Pimoroni). The dimensions of the NEMA17 stepper motor is as follows, where L MAX = 40mm: