[time-nuts] Visual clock comparison

Chuck Harris cfharris at erols.com
Mon Apr 20 15:24:43 UTC 2015


Yes, I meant 18000 BPH.  My fingers have a mind of
their own and type things that I don't always want.

I apologize for my many and varied imperfections.

I never said that 18000BPH was the only rate used...
only that "standard stopwatch ticks" are 18000BPH.

An Elgin "Jitterbug" is anything but a standard
stopwatch.  A variant of the Elgin was used with
the Norden Bomb sight... Probably the only mechanical
stopwatch in history to be classified as top secret
by the US Govt..  (If your Elgin was last serviced
more than a year ago, I would venture that it no
longer runs at 40BPS.)

18000BPH was the standard beat for pocket watches and
wrist watches when stopwatches were invented.  18000BPH
is where any reference to 5 beats per second comes from.
18000BPH is where the 0.2 second limit on conventional
stop watches comes from.

And, 18000BPH is what you will get if you buy a
normal mechanical stopwatch... Which, oddly enough,
you can still buy.

-Chuck Harris


Bill Beam wrote:
> On Sun, 19 Apr 2015 23:25:10 -0400, Chuck Harris wrote:
>
>> 1/5th second is simply the rate at which the balance
>> wheel on a standard stopwatch ticks... 18000BPM.
>
>> -Chuck Harris
>
> You must mean 18000BPH.
>
> There are many balance wheel rates in use from 4.5BPS to 10BPS and higher.
> My Elgin "jitterbug" stopwatch runs at 40BPS.
>
>
>
> Bill Beam
> NL7F



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