Rolling-Dome Trunk Vertebra
A Ø50 x 3 mm spine disc for the 'SG90 Tendon-Driven Continuum Trunk Arm' kit, printed ×8. It has a Ø12 hub topped by a R7.5 rolling dome with its apex at 12 mm, which sets the 12 mm stacking pitch. The 4.6 mm bore rides loosely on the 4 mm OD PTFE backbone so each segment can tilt. Three chamfered 1.8 mm holes at R20 guide the 0.8–1.0 mm braided tendons, and three Ø10 lightening holes keep each disc to about 6 cm³.
robotics kit continuum-robot tendon-driven