Trunk Tip Anchor Cap
This is the end cap of the 'SG90 Tendon-Driven Continuum Trunk Arm' kit. It is a Ø50 x 4 mm flat-bottomed disc that sits on the dome of the last vertebra. Its blind 4.3 mm bore takes the 4 mm OD PTFE backbone, which you lock with an M3x8 set (grub) screw in a radial 2.6 mm hole at z=8. You drive that screw with a hex key through a 3.4 mm access tunnel in the +X boss. Three 1.8 mm tendon holes at R20 take 0.8–1.0 mm braided line, and each has a Ø4 knot counterbore on top. Two Ø9 bosses at ±14 mm hold M3 heat-set inserts (4.0 x 6 mm bores). Their tops are flush with the Ø14 centre boss at z=18, so a payload bolts onto one flat plane.
robotics kit continuum-robot tendon