Slotted Servo Crank Arm
A 37 mm long, 4 mm thick flat crank for the 'MG90S Six-Servo Stewart Platform' kit (print ×6). It fits over a stock MG90S single-arm horn: the horn keys into a 6 mm wide, 1 mm deep recess on the underside and is fixed with two M2 self-tappers through a 2.4 mm radial slot. The slot runs from 6 to 16 mm radius, so the horn's hole spacing doesn't need to be known. A 7.5 mm centre hole clears the horn screw, and a 10 mm tip boss has an M3 clearance hole 24.0 mm from the shaft that takes the pushrod ball-stud tab with an M3x16 screw and a nylock nut.
robotics kit mg90s servo-horn