Bench Warning: Verify Motor Zero First!
Before screwing the aluminum horn to the splined shaft, supply 1500µs PWM (90°). If assembled at 0° or 180°, the limb will strike hard mechanical limits and strip internal reduction gears upon boot!
"Why Two Sides on Each Motor?"
Standard humanoid U-brackets sandwich the servo: Side A is the active 25T splined horn driven by the motor, while Side B is an idle chrome flanged ball bearing. This gives true dual-axis structural rigidity without paying for industrial twin-shaft actuators!