3D Printed Hanging Internal Gear Clock




About: I am a robotic engineer, and I like to make things and teach others.

Before I became a robotic engineer I had an internship designing gears. I thought it would be fun to use what I learned for the 3D design contest. This clock all hangs from the top pinion, which is to be driven by the minute shaft of a clock motor (or 1 rev per hour timing motor if you can find one). The minute wheel, counter weighted by a bolt on the back, in turn, hangs from the hour wheel.

The three printed parts to make this are attached as STL files below, if another format is preferred ask in the comments and I will put them up if possible.

The following Non-printed parts are needed
  • Some wide heavy washers and a screw to hold them on the back of the minute (lowest) wheel. These act to keep it in place and to counterweight the front.
  • The motor
Additional mounting will need to be made to fit your motor. For ease of integration I have put a pilot hole on the back of the drive cog. It is suggested that a pair of bolts with skateboard bearings be used to support the drive wheel, but I didn't include this because, again, it depends on your motor mounting solution.

Based on feedback I will be making variations and additions to this design, without putting it out I don't know what may be requested, perhaps smaller or larger teeth, different numbers, or some example motor mounts.

I will be updating more soon, please make suggestions when you reply, this Instructable is still a live project for me, and I will grow it with feedback. And if you like it please vote for me in the 3D design contest.



  • Arduino Contest 2019

    Arduino Contest 2019
  • Woodworking Contest

    Woodworking Contest
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    IoT Challenge

10 Discussions


1 year ago

Awesome! I would like to make this out of wood, do you have any dimensional drawings you can share? Centimeters/Inches doesnt matter, I'm flexible. Thanks!


6 years ago on Introduction

I'm trying to make this at work (we sell laser cutting machines), but so far no luck! I think you'll need to double the amount of teeth to have a bit more accuracy. Also the minute wheel doesn't always turn smoothly. Yesterday we've cut a test sheet for the first time, but the design was too small. Here are some pictures of the new design (30cm exterior wheel instead of 15cm). You can also find some pictures of the test piece that we made.

5 replies

Reply 5 years ago on Introduction

Nice! i was trying to do the same thing and found i will be too in-accurate because the minute face walks up the side a little. i then re designed it so the minutes were fixed on a shaft but still turned by the hours, this didn't work either as any slight hints of friction on the shaft, walked the hour gear across, jamming the gears. this is why now my design doesn't have a hanging minute face but has it on the top gear.

clock no bottom support..jpgIMG_20130607_122018_0.jpgclock..tiffIMG_20130610_173810_0.jpg

That's a beautiful design. I'm kind of wishing I could reboot this instructable, since the innitial post was kind of rushed. But I can always update it. I've found that the teeth can be smaller, more of the drive can be integrated at the top, and the numbers on the minute wheel should be more visible. I guess the best thing would be to make a version 2 instructable.

Thanks! Once i get this clock finished i will publish the instructables. Making a Mark two instructables sounds good, i would like to see your take on this design and what works and what doesn't.

Wow, it looks like you redesigned it. Did you do it from scratch or modify the designs somehow? Since you're working so much on it I'll help you out. The teeth I designed were meant to work in plastic, they might not work with the higher friction and weight of steel. What size would you like? Details like the thickness of the metal could help too.


5 years ago on Introduction

I made it a bit bigger than before, but i still need to trim the edges to see if it'll run smooth. But i'm also having doubts about the accuracy. I think it should be 2 or 3 times the amount of teeth...