A 3D-printed mechanical pendulum clock, built in November and December 2025.
I'm not sure what got me interested in this, other than just being interested in machinery in general. At some point I'd like to make clockworks from metal, but 3D printing is just a lot easier, so I figured I'd mess around with that. I did the escapement just before this.
I bought these plans and just followed them. They are quite good.
Printing (November 2025)
The clock print has started. Here's the dial ring, with its Roman numerals.
And a build plate of red parts: three large spoked gears, a threaded post on a tripod base, and some small spacers and bushings.
Assembled (December 2025)
The clock is assembled! And does not work at all. Debugging ahead.
It's hanging on a rough wooden board, with the white dial, red gear train, black hands, and a black pendulum with a gold bob. The weight is a gold cylinder hanging from a string.
For debugging, I just pushed on the various gears to see whether the escapement was moving. It stops moving at one point in the gear train, so that's where I'll go look for friction. I guess that's my printf. It will take me an hour to disassemble it, clean out the bearings, and put it all back together again. If I'm lucky, an hour.
That's one of the things I like best about mechanical stuff: to me, the answer is often super obvious. In robotics, we have a joke. If it's software, it takes eight hours to find and five minutes to fix. If it's mechanical, it takes five minutes to find and eight hours to fix. If it's electrical, it takes eight hours to find and eight hours to fix.
Update October 2026
I did eventually get the clock working, although I had to put a lot more weight on it than I would have liked. But it ran great: it was within a minute a day after I tuned it. For a while. Then it started stopping every few days. Then every few hours. Now it just hangs on my wall and doesn't move. I can get it to tick for a bit, but somewhere inside, some sort of friction has built up. With gear ratios as high as a clock needs to have, any little thing can be a problem.
Hopefully I'll debug it again at some point, because it really is a cool project. I don't regret building it. I just wish it was ticking away rather than just being wall art.