Long Term Accuracy

A project log for Bendulum Clock

A new kind of electromechanical clock

Dave EhnebuskeDave Ehnebuske 06/01/2021 at 17:090 Comments

It's now more than four years later, and I'm pleased to note that the bendulum clock has simply faded into the background as I've moved on to other projects.

It's been running continuously since March 2017, except for a period of a couple of months when I moved from the East Coast to the Pacific Northwest. Other than for the move, it's had no maintenance and little attention. I still like it a lot, and people who see it for the first time always ask about it, but it's now "just a clock." That's terrific.

After running it for this much time, I can say its long-term accuracy really surprises me: it's better than a traditional "grandmother" pendulum clock I also have. I adjust the pendulum clock by a minute or so once a week when I pull up its weights. I adjust the bendulum clock by the same amount when I notice it's off, more or less once a month.

I notice it drifts most when the ambient temperature varies diurnally during the summer months. During the winter months when the central heating is on and the temperature only varies by about 1ºC it's often correct to within a minute for several months. Good enough for me!