Many, many mechanisms require gears, but the good news is that plastic gears are very cheap. The bad news is that you have to buy a lot of them at once and that means you need to know ahead of time what gears you need. Being able to make gears on-demand would be very convenient, but most 3D printers lack the tolerance to do it well and CNC setups get expensive. But by following Mr Innovative’s recent video, you can build your own affordable machine that automatically cuts gears.

This might be able to handle very soft metals, but it is really meant for cutting nylon and other plastics. Users can set the diameter and the number of teeth, which together dictate the pitch. However, they can not change the tooth cut profile without swapping out the blade. They set the parameters on a Nextion LCD touchscreen and then the machine takes care of the rest. It rotates the gear by the calculated pitch, then moves the gear into the circular cutting blade according to the set diameter.

An Arduino Nano board interfaces with the Nextion LCD and controls the two stepper motors through drivers on a custom shield, as well as the large DC motor that spins the blade. The gear blank mounts directly onto one stepper motor via a coupler, while the second stepper motor controls the linear motion through a lead screw. The frame is a combination of aluminum extrusion and 3D-printed parts, with bearing blocks for the linear movement.

A maker could buy a lot of gears with the money it takes to build this machine, but the ability to cut custom gears to exact specifications whenever necessary would be very handy.