This model is a very compact motor-reducer, with precise movement and without backlash. The overall height is 29mm, only 6mm more than the motor shaft.

The reduction ratio is (1 + 38/14) : 1 , roughly 3.7 : 1

Print instructions

The model is designed for SLA printers, but a good FDM printer can do the job either.

For SLA printers

• Print the Full Assembly.3mf file, arranging the parts on the build plate (no print in place)
• Use the slow print profile to get maximum dimensional precision
• Print the parts with an engineering resin, such as SUNLU nylon-like resin or JAMG-HE Conjure Rigid resin

For FDM printers

• Print the Full assembly (for FDM printers).stl file, arranging the parts on the build plate (no print in place)
• Use an high precision, low layer height print profile

Build instructions

Screws

• 4x M3x6 hex socket head
• 4x M3x8 hex socket head
• 4x M3x20 hex socket head
• 4x M3 nut

Mount the rotor first, taking care to insert the box lid between the planets section and the end section. Secure the 3 rotor sections using the 4 20mm screws. 

Place the rotor into the box and insert the central gear on the motor shaft.

Fix the box to the motor using the 4 6mm screws: put them in position in the 4 corner housings with the help of tweezers and tighten them by inserting an allen key in each of the 4 holes of the cover.

Finally, insert 4 M3 nuts into the 4 corner slots of the box and secure the lid with the 4 8mm screws.

Lubricate abundantly all the moving parts with lithium grease or similar.