4 ms·

Thought this was very interesting - https://www.theguardian.com/science/2015/apr/19/clockmaker-john-harrison-vindicated-250-years-absurd-claims https://www.theg

Thought this was very interesting - https://www.theguardian.com/science/2015/apr/19/clockmaker-john-harrison-vindicated-250-years-absurd-claims https://www.theguardian.com/science/2015/apr/19/clockmaker-j... It mentions - "scientists revealed that a clock that had been built to the clockmaker’s exact specifications had run for 100 days during official tests and had lost only five-eighths of a second in that period." While "a typical quartz clock or wristwatch will gain or lose 15 seconds per 30 days" (https://en.wikipedia.org/wiki/Quartz_clock#Accuracy https://en.wikipedia.org/wiki/Quartz_clock#Accuracy). You can get temperature compensated quartz watches etc. though, which perform better apparently, but found it pretty interesting that a mechanical clock can best standard quartz technology.

BiteCode_dev 3y ago
That's certainly hasn't been my experience, all my watches have kept an accuracy if a few seconds over a year.
labcomputer 3y ago
That greatly undersells the accuracy of quartz watches. An individual unit may gain or lose 15 seconds per month (though that level of inaccuracy would be unusual), but that given unit will consistently gain or lose almost the exact same amount of time every month. After you have measured the relative speed of a given quartz movement, it becomes trivial to obtain the correct time (for, e.g., navigation purposes). For what it’s worth, the NBS and US Naval Observatory switched from mechanical (pendulum) clocks to quartz during the Great Depression.
- canjobear 3y ago
  If it's known to lose a reliable amount of time per month, can't you recalibrate it to make it that much slower?
  - AlotOfReading 3y ago
    It's a pain in the butt. Recalibration means physically trimming the crystal. Which side you trim depends on whether it's too fast or too slow. It's really fiddly though (especially too slow, which requires grinding the ends down instead of the face). Even in the 20s they would have been producing these dozens at a time with a big lapping wheel, so they could just pick a better crystal from the same batch.
    - jstanley 3y ago
      It would be possible to make the IC adjustable (e.g. a tiny microcontroller) so that it could compensate for the difference without having to modify the crystal.

BiteCode_dev 3y ago

That's certainly hasn't been my experience, all my watches have kept an accuracy if a few seconds over a year.

labcomputer 3y ago

That greatly undersells the accuracy of quartz watches. An individual unit may gain or lose 15 seconds per month (though that level of inaccuracy would be unusual), but that given unit will consistently gain or lose almost the exact same amount of time every month. After you have measured the relative speed of a given quartz movement, it becomes trivial to obtain the correct time (for, e.g., navigation purposes). For what it’s worth, the NBS and US Naval Observatory switched from mechanical (pendulum) clocks to quartz during the Great Depression.

canjobear 3y ago
If it's known to lose a reliable amount of time per month, can't you recalibrate it to make it that much slower?
- AlotOfReading 3y ago
  It's a pain in the butt. Recalibration means physically trimming the crystal. Which side you trim depends on whether it's too fast or too slow. It's really fiddly though (especially too slow, which requires grinding the ends down instead of the face). Even in the 20s they would have been producing these dozens at a time with a big lapping wheel, so they could just pick a better crystal from the same batch.
  - jstanley 3y ago
    It would be possible to make the IC adjustable (e.g. a tiny microcontroller) so that it could compensate for the difference without having to modify the crystal.