One nice thing about gears is that if you know any two things about them – let’s say outer diameter and number of teeth — you can use some simple equations to find everything else you need to know, including the correct center distance between them. In this project, we’ll design and fabricate spur gears using free software (Inkscape) and an online store ( that does custom laser cutting at affordable prices out of a variety of materials. If you have access to a laser cutter at a local school or hackerspace, even better! You can also print out the template and fix it to cardboard or wood to cut the gears by hand.

This project is adapted from a blog post a student did in my first Mechanisms and Things That Move class at NYU’s ITP.