Herringbone Planetary Gear Bearing

A planetary gear set that prints already assembled: the interlocking herringbone gears could never be put together after manufacture, so it can only be made by 3D printing. Designed by Emmett Lalish.

Use it to show how planetary gears (in car gearboxes, drills and wind turbines) work, and as a discussion starter on what additive manufacturing can make that other methods cannot.

Design by Prusa Research on Printables, shared under CC BY-SA 4.0. The files and photos are the designer's, unchanged.

1. Print at 0.1 mm layers (about 3 hours). Break the parts free gently by turning the centre.
2. Hold the ring still and turn the sun gear: what do the planets do?
3. Discuss: why can't this be made by moulding and then assembled?