This past Christmas season I put my printer to good use making unique presents for my family. Everyone with a workshop or a garage got a custom geared light switch cover.

Designing this toy definitely took a few tries to get the desired effect. While doing so I researched and collected notes on perfecting printed gears and I thought it was interesting enough to share. This Instructable is intended as a general guide for designing & printing FDM 3D printed plastic gears.

The geared light switch cover is a neat example of something you should be able to design on your own after reading this instructable.

For those of you who have a 3D printer: you can find the STL files attached to this step for free!

  • (Please note the 'personal use only' licence for this design, this means- No Sharing, selling, or remixing to share/sell. Please don't use my files to compete with me.)
  • (The assembled device measures 6.25" in diameter. The largest printed part is 5.875" diameter)

For those without a 3D Printer: I am selling finished Geared Light Switch Covers on my blog here.

Step 1: Printing & Assembly Instructions for Geared Light Switch

Print all parts minimum 3 perimeters all sides top & bottom, with 15% infill. I recommend 0.3mm layer thickness maximum. Any material will work as long as you can prevent warping, which would devastate this device.

The wrench file is the only one that needs print supports/scaffolding.

Assembly Instructions: (Read in full before starting)

1. Clean up the gear teeth with a razor blade so they will mesh smoothly then place them on the plate in the same rotational orientation they were when you printed them. (The pin on the sun gear is to the right and the handle of the ring gear is top and center.)

2. Pin the planet gears in place by pressing the nuts into the holes.

3. Apply a smidge of clear drying glue (glue stick works well) to the business end of the wrench then install it from the side so it snaps on the nut. The glue is to keep the wrench attached to the nut. The wrench also holds the sun gear down onto the assembly.

4. Soften the clips using a heat gun for ~10 seconds. Just enough so they can be opened up. Then align the bump on the clip with the hole on the back of the plate and press over the ring gear. (The holes on the back of the plate may need cleaned up with a knife to aid this, depending on how good your printer is). Then squeeze the clip as it cools. This will ensure that everything is securely held together.

<p>Very thoroughly written; there's lots to be learned here, so thanks for sharing your knowledge!</p>
Not bad! I was curious as to how you went around generating the involut&eacute; gears. I never had the luxury of a good generator or script runner so did mine by hand with straight line approximation. Because of the STL conversion I lost nothing and they worked nicely nonetheless.
<p>Onshape.com is free for the first 100 MB and has an open-source code for Feature Script commands, one of which generates involute gears. I made a gear set to run my son's Tonka with an automotive window crank motor.</p>
<p>That's a great resource, all the links in one place! Thanks for sharing that, very cool! </p>
<p>Very nice Instructable with lots of good resources! One you left out is one of my favorites: FreeCAD (https://www.freecadweb.org/ ). Has a nice gear generator built in and can be used to create the rest of your machine's design as well.</p>
<p>This is an incredibly well done instructable which would have saved me a lot of time if I had had it before. Thank you very very much, this is sure to be an often-used bookmark in the future :)</p>
<p>This Instructable is great! The first gears I modelled used the typical circle-shaped teeth and the meshing was absolutely horrific. I also love the resources you linked to. Great work!</p>
<p>Incredible resource you have here! I feel like this is the basis of an extremely complex but very interesting book. Gears have always interested me. Such a simple concept to understand but can reach such intensely complicated levels. I tossed you a few votes, good luck in the contests!</p>
<p>Thanks so much, glad you like it!</p>
<p>Couldn't understand a word but the pictures look great! ;)</p>

About This Instructable




Bio: Hi I'm Michael! I'm a dog owner, husband, writer, and mechanical engineer and I love getting my hands dirty building stuff. If you ... More »
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