Tri-Spoke Servo Base Plate
This is the Ø160 x 5 mm foundation plate for the 'SG90 3-DOF Ball-Balancing Platform' kit. It has three spokes at 90°, 210° and 330°, and each spoke holds one SG90 servo cradle with two M3x12 SHCS. The M3 holes are 3.4 mm, at radius 30 and 60 mm, with captured M3 hex-nut pockets (5.7 mm AF x 2.6 mm deep) on the underside. In the centre, a 3x3 grid of M3 holes on a 20 mm pitch takes standoffs for a PCA9685 or Arduino. Three rounded cut-outs bring the plate under 80 cm³ while keeping 6 mm webs and an 8 mm outer ring.
robotics kit sg90 ball-balancing