My shot at designing a planetary gear that can be printed in one shot. Designed parametrically in Solidworks with formula from Machinery's Handbook. The sun gear has 20 teeth, the planet gears have 8 teeth, and the internal gear has 36 teeth. After a few prints with varying clearance, I found the best version to have about 0.008"-0.010" clearance. It is somewhat stiff right after printing, but loosens up after moving.