3D Printed Post Modern Grandfather Clock

Projects can often spiral, not down or up, but out. For [Derek] he started playing around with a 3D printed escapement mechanism and thought it was a wonderful bit of engineering. But with a simple drum and weight, it only had a runtime of a few minutes. What started as a simple “can I make it run longer” spiraled into a full-blown beautiful grandfather clock.

A gear drive, a ratcheted winding sprocket, and a ball chain gave the clock about one hundred minutes of runtime. Adding a recharging mechanism was fairly straightforward. The weight automatically rewinds with the help of an ESP32, a motor, and some limit switches. While an ESP32 is absolutely overkill for this simple project, it was cheap and on hand. A quick hall effect sensor to detect the pendulum passing made it into a proper clock. Considering it’s a printed plastic clock, losing only 2-3 seconds per day is incredibly good. The whole thing is wrapped in a gorgeous wood case with a distinct design.

Surprisingly, everything was designed in OpenSCAD and Blender. [Derek] includes some great tips such as cleaning out the ball bearings to make them run smoother and suggestions on how to make a plastic clock move without binding. Clock making is a complex and sometimes arcane art, which makes watching the process all the more interesting.

18 thoughts on “3D Printed Post Modern Grandfather Clock

  1. Very cool proof of concept but 100 minutes of run time? We have a not even fancy cucko clock from Germany that uses weights and runs for several days, would be a week maybe if we mounted it higher up (the weights hit the floor) but mom wanted it at her (low) eye level. I guess if this click is auto winding there isn’t need to increase the efficiency of the escapement per se but sounds like a a lot of room for experimenting.

  2. Hello Derek,
    excellent choice for an escapement! Arnfield indented this in 1987, is is a true constant force escapement, the unlocking for the recharge is not done by the pendulum.

    That it worked out of the box is remarkable. Congratulations to the designer of the stösst files!

    You should make the weight of the impulsing arm lighter. This will decrease the amplitude and hence improve precision. I don’t think that you gan go for +/-2.5 deg, this would be a goof value for a decent clock, precision clocks use even less.

    Decreasing the weight might give you trouble with recharging though. But it wood allow you to reduce the driving weight or use a higher ratio in the gears.

    If you want to dig deeper into clock building, you might be interested in a good reading by borrowing Prof. P. Woodwards „my own right time“. He built a precision clock also passing Arnfields concept but finally settling onto a Master Slave configuration.


  3. The rumbling trains on the Red Line subway have a reputation for ruining many MIT laboratory experiments, video presentations, holograms etc Watch a video from a Kendall Square startup and for sure you will hear the rumble. One of the reasons why the best work at MIT is done in the wee hours of the morning when the subway is not running, I wonder what its effect would be on this clock

  4. Actually it does just that. At startup it goes through a calibration phase where it measures its own pendulum period using the esp32 microsecond hardware timer. That’s what it then uses to convert swing counts into elapsed time. This is analogous to adjusting the pendulum length on a conventional pure mechanical clock.

    1. If the controller were to continuously measure and adjust the calibration to “adjust the pendulum length”, it would simply be using its own clock, or the network clock as the time standard, and ignoring what the pendulum is doing. The pendulum swing then simply defines the update interval, not the time.

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