# 3D Design / 3D Scanning / 3D Modeling > 3D Printing Gallery >  Quarantine prints - 5. Pendulum Clock

## jamcultur

I'm making a weight-driven pendulum clock based on a clock that Benjamin Franklin invented in the 1750s. It was common for clocks of that time to just have one hand because they were easier to make and cheaper than clocks with two hands. Those clocks only had an hour hand, and you couldn't read the minutes from them. Franklin's clock has one hand that tells both the hours and the minutes. A few clock makers in England and Germany made versions of it in the late 1700s, but it never caught on, probably because people didn't know how to read the time from them. The dial has the hour numbers arranged in a spiral starting from 12 at the top, spiraling in to 11 at the center. You have to know approximately what time it is to read the time. If you click on the thumbnail of my dial design, you'll see that the hand indicates either 12:30, 4:30, or 8:30.

I'm keeping my version as simple as possible to make it easy to print, assemble, and get working. I want it to look modern, rather than like an imitation of an antique Franklin clock. So far, I've printed a set of gears and a test jig. It took several tries to print gears that worked as well as I wanted. I've made some simple mechanisms in the past, but clocks require a higher degree of precision than anything I've ever printed before. You can click on this link to see a video of a test of the gears:
https://drive.google.com/file/d/1exqHeHWEpXEbsp1CjD2XOuh1HRYz8qB-/view?usp=sharing

With a few ounces of weight on the biggest gear, the smallest one turns at over 1000 rpm. That's 1000 times faster than the gears would turn in the clock, but it's a good indication that friction is low and that the gears are meshing properly. I have a lot of work left to do to make a working clock, but I'm encouraged by the progress so far. Here's some more information on Franklin's clock:
https://founders.archives.gov/documents/Franklin/01-08-02-0060

Click on a thumbnail to enlarge the image.

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