NEMA 17 Belt Reduction Bearing Plate
A 106 x 52 mm mounting plate that turns a NEMA 17 into a 3:1 belt reduction: the motor bolts to the top on the verified 31 mm square pattern with its shaft dropping through a 23 mm pilot clearance, and an 8 mm output shaft runs in two press-fit 608 bearings in a 34 mm tower at 58.5 mm centres — the right spacing for 20T to 60T GT2 pulleys on a 200 mm closed-loop belt. Gussets take the belt pull in the XY plane, and four M4 holes on a 92.5 x 37 mm rectangle bolt it to a chassis deck on 20 mm standoffs so the belt runs underneath.
robotics nema17 gt2 608-bearing