[time-nuts] ADEV data for mechanical clocks

Tom Van Baak tvb at LeapSecond.com
Wed Mar 7 09:11:17 EST 2018


> Does anybody have any ADEV data for mechanical clocks?  (I didn't find any by 
> google, but there was a lot of noise so maybe I missed something.)

Hal,

It's often buried in out-of-print horological books or magazines / journals / articles that google may or may not index.

I have some ADEV examples here:

http://www.leapsecond.com/pages/m21/ -- the classic Navy chronometer
http://www.leapsecond.com/pend/shortt/  -- see Stable32 / Timelab plots
http://www.leapsecond.com/pend/clockb/  -- go to technical links
http://www.leapsecond.com/hsn2006/  -- see dream pendulum paper

> I'd expect a watch to slow down slightly as the spring unwinds.  That 
> probably doesn't apply to clocks driven by weights.

Clockmakers are clever and implement methods to keep constant power:

https://en.wikipedia.org/wiki/Fusee_(horology)
https://en.wikipedia.org/wiki/Maintaining_power

Photo:
https://www.wired.com/wp-content/uploads/archive/images/slideshow/2007/12/gallery_time_hackers/disk.jpg
via https://www.wired.com/2008/01/gallery-time-hackers/

Diagrams:
http://www.hamiltonparts.com/m21-6.jpg
http://www.hamiltonparts.com/m21-8.jpg
via  http://www.hamiltonparts.com/hamilton.htm

Additional photos:
https://chronometerbookdotcom.files.wordpress.com/2017/11/broken-chain-labelled1.jpg
via https://chronometerbook.com/2017/11/

https://chronometerbookdotcom.files.wordpress.com/2017/02/attach-to-fusee-1.jpg
via https://chronometerbook.com/2017/02/13/27-fusee-chain-substitute/

/tvb



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