Planetary gearset 4:1, module 1.5

Description

Textbook planetary layout: ring teeth = sun + 2x planet, 54 = 18 + 2x18. Hold the ring, drive the sun, and the carrier turns at 4:1.

All four parts sit in one file exactly as they assemble, which makes it easy to check the mesh in your slicer before committing. Split by object if you want one STL per part; every slicer can do it.

The 0.16 mm layer is not fussiness. At module 1.5 the tooth is 3.4 mm tall, and at 0.2 mm the involute turns into a staircase near the tip. Carrier and pins are not included: you need a 5 mm shaft and three 4 mm pins.