100:1 Gearbox With Hobby Motor Mount

100:1 Compound Spur Gearbox for Micro DC Motors

I originally designed this gearbox while building a cam and shaft mechanism to animate a cardboard cutout. The project needed a super lightweight motor that could turn very slowly while still providing enough torque to drive the mechanism smoothly. After experimenting with several gear trains, I settled on this 100:1 compound spur gearbox.

The gearbox is designed around a common 030 Micro DC Motor and is fully enclosed to help keep the gears aligned and protected. While it was built for my own project, it should also work well for other similar applications.

Included in the files are 2 variations of the frame, one with support the twist-on stand, and the other without.

Features

100:1 compound spur gear reduction

Designed for the 030 Micro DC Motor or similar: Amazon

Fully enclosed housing with a removable lid

Large output shaft for transferring torque

Compact-ish footprint that's easy to integrate into projects (I'll be working on reducing it when I have time)

Low filament & time cost

Hardware Required

1× 030 Micro DC Motor or similar

4× M2.5 screws to secure the lid

Everything else is included in the printable files.

Assembly

The gearbox is made up of a the main housing, three gear stages with a output shaft, and a removable lid. I'd recommend mounting the motor first, and then attaching the first 12T gear (may need adhesive depending on tolerances). After that, mount the other gears (follow the model pictures), and then secure the lid using three M2.5 screws.

Additionally, there are two versions of the gearbox, one with a modified twist on base for standing upright, and the other as just the basic cylindrical gearbox with the motor mount sticking out. I'll probably add in a screw mounted variation here shortly.

Depending on your printer's tolerances, you may need to lightly clean up the shaft holes or add a small amount of dry PTFE lubricant to help the gears run more smoothly (those micro motors don't have a ton of torque so they need the help).

Notes

This is the first version of the gearbox and was designed specifically for my cam-driven animation project. If you end up using it in another project or have ideas for improvements, I'd love to see what you build and hear your feedback.