SG90 Tendon Capstan Drum
This capstan drum is part of the 'SG90 Tendon-Driven Continuum Trunk Arm' kit (print ×3). It keys onto the SG90's stock single-arm horn through a 7.5 x 2.5 mm underside slot and is held by an M2x10 screw that goes through a 2.4 mm hole with a Ø4.5 counterbore. A 0.8–1.0 mm braided tendon ties through a 1.8 mm cross hole in the Ø20 groove, which pulls in 31 mm of line per 180°. The drum is 12 mm tall with Ø28 flanges, and 45° chamfers on the flanges keep the line in the groove.
robotics kit sg90 capstan