This is a 1 : 232.5 gearbox utilizing double annulus planetary gear. First stage 8 : 31 gears reduce motor speed to the sun gear, then the planetary gears reduce it further by 1 : 60. The output is the second, smaller annulus (but with more teeth). It produces a lot of noise.
Some holes are 3.2mm by design, which should allow a 3mm screw to rotate freely inside. Others are smaller and meant to be tapped for 3mm screw. Those holes are: - All holes in motor support - All holes in carrier
Screws (length) needed: 6 mm x3 for each planet gear axle, put on the carrier 20mm x4 for joining annulus to motor support 30mm (+ 1 nut) for main axle