[time-nuts] Antique pendulum clocks

[Bill Beam]

On Tue, 19 Nov 2019 20:10:14 -0500, Philip Gladstone wrote:

>I've started to monitor the individual ticks on a grandfather clock from
>the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a
>light beam.

>The data that I get is surprising in that the pendulum swing varies
>according to the position of the hands on the clock. It appears that the
>amplitude of the swing depends on the driving force imparted by the
>escapement. Since the second hand is not counterweighted, there is slightly
>more energy available to drive the escapement during the first half of each
>minute and slightly less in the second half. There is much bigger effect at
>the end of each hour when the mechanism has to move a lever to trigger the
>strike mechanism. This 'end of hour' effect changes the pendulum swing
>enough so that the period is noticeably affected (maybe by 300ppm)

>Anyway, my google-fu did not reveal anybody else interested in this
>stuff... Anybody here interested?


Most people interested in this problem have been dead for about 200 years.
Also note that as the clock gets old and dirty it will begin to stop at 8:45.

Now if you want to see another old interesting clock problem look up the
'Thursday afternoon effect'.

>Philip
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Bill Beam
NL7F