Parallel Follower Leg Link
This is the passive follower link for the 'SG90 Parallelogram-Leg Biped Walker' kit. It is 74 x 14 x 6 mm, has full-round R7 ends and two 3.4 mm pivot holes exactly 60.0 mm apart, and a 1.5 x 8 mm stiffening rib runs between them. The top end bolts to the torso's I4 slot and the bottom end to the ankle lug's inboard face, each with an M3x20 socket head screw, washers and an M3 nyloc nut, so the ankle stays level as the leg swings.
robotics kit biped parallelogram-linkage