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I wonder if this article got inspired by the recent movie Project Hail Mary?

Another thing related to this subject is the frequency in watch making. I own a manual winding watch that I wear everyday. It is certainly an engineering marvel. These watches are ticking by the hair spring and its frequencies are targeted to 2.5Hz to 4Hz (5 times per second, or 8 times per second). I don't know the rationale behind these numbers. I guess that they must have been a combination of engineering constraints and finding a good balance to keep every second accurate.



2.5 Hz was the standard in big pocket watches, with a big balance wheel. 4 Hz is the standard for wristwatches, with a smaller balance wheel.

You are right that it is an engineering compromise. Higher frequencies mean a greater acceleration of the balance wheel. The inertia of the balance wheel is itself a compromise with the strength of the main spring. You want to have a large oscillation amplitude, but also that the watch can self-start, and not too much pressure on the escapement's contact points.

5 Hz is, surprisingly, a big engineering gap especially with regards to lubrication: only dry lubricants work, and it was figured out (at scale) only in 1969 by Zenith with their "El Primero" movement (which is still in production and is a major milestone in watchmaking for many reasons, on top of having a crazy history).

But when Rolex decided to use El Primero movements in their second version of the Cosmograph Daytona, they reverted it back to 4 Hz to avoid having to retrain all the watchmakers in their vast service network.


Esthetism also counts, a high frequency means a smoother second hand movement. It is one metric watchmakers are fighting on. I found this article that sum it up quite well : https://www.ethoswatches.com/the-watch-guide/mechanical-watc...




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