12-25-2023 - Note: Some people have said that the “shoulder” on the outer gears interferes with the inner gears. Every printer has slightly different tolerances, so this may not be an issue for everyone. Please know that the shoulder is there to prevent the smaller gears from lifting during drawing. If your gears have this issue, simply expand the z dimension of your outer ring gear slightly then reslice and reprint. Stretching the Z slightly should not affect how the gears mesh. Please continue to give me feedback! Thank you!

This spirograph gear set will provide you and your kiddos with hours of fun and creativity! I have provided 2 “outer ring” gears of 120 teeth and 100 teeth. Then I have 8 circular gears and 2 elliptical gears all with varying sizes and numbers of teeth. One thing I learned while doing this is that designing and using spirographs is a very mathematical endeavor. The pattern that is produced is directly a result of the ratio of teeth in the outer and inner gears. So depending on the gear combination you use, you could get a pattern with only a few nodes, or one with many. The hole you choose to create the pattern with will determine the “frequency” or size of your pattern, allowing for some very interesting variations as well.

So the choice is yours! Will you experiment with the mathematics and use an analysis of your pattern to determine your gear ratio? Or will you create some works of art using different colors and overlapping patterns? With these 12 different gears and several hole positions on each gear, the possible artwork you could create is nearly endless!

I provided some 3MF files for easy printing, but you could also print gears individually if desired. I included the number of teeth on each gear in the file name if you're curious. As a general rule, if the larger gear is divisible by the lower gear, the more simple your pattern will be. If you use gears with odd numbers of teeth, your pattern will be more dense/intricate. Let me know what you think! I am open to designing more gears and adding them, just leave me some feedback of what you'd like. My email is vanadium14@gmail.com

Happy printing and enjoy!