shorten a pendulum

Dan Lurey

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Dec 26, 1996, 3:00:00 AM12/26/96

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Friends,
I need to shorten the pendulum of a newly purchased Grandfather clock
movement, to fit in a shorter "Grandmother" case; about 6 inches. Is
there some adjustment in the movement to allow the shorter pendulum to
oscillate more slowly?

Thanks
Dan Lurey

Murray R. Falk

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Dec 27, 1996, 3:00:00 AM12/27/96

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In short, (NPI), No.

New movements are made in several pendulum lengths. You did not
get the right one. What you should now do with the new movement, is
to exchange it at the seller's for one of the correct Pendulum Length.

The only change that would simultaneously shorten the pendulum length
and change the speed of the hands to match the more rapid rate, would
also involve the changing of several gears inside the clock movement,
which would in all probability, cost much more than you paid for the
replacement.

Hope this helps.

Murray, Calgary

Murray R. Falk, Proprietor
ABOUT TIME CLOCK SERVICE
2112 - Palisdale Road, S.W.
Calgary, Alberta, Canada
T2V 3T6

e-mail: fa...@cadvision.com
voice : (403) 281-3024

Paul Blakeslee

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Dec 30, 1996, 3:00:00 AM12/30/96

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fa...@cadvision.com (Murray R. Falk) wrote:

>In article <32C308...@starnetinc.com>, Dan Lurey <spa...@starnetinc.com> says:
>>
>>Friends,
>> I need to shorten the pendulum of a newly purchased Grandfather clock
>>movement, to fit in a shorter "Grandmother" case; about 6 inches. Is
>>there some adjustment in the movement to allow the shorter pendulum to
>>oscillate more slowly?
>>
>>Thanks
>>Dan Lurey

>In short, (NPI), No.
>
>New movements are made in several pendulum lengths. You did not
>get the right one. What you should now do with the new movement, is
>to exchange it at the seller's for one of the correct Pendulum Length.

>The only change that would simultaneously shorten the pendulum length
>and change the speed of the hands to match the more rapid rate, would
>also involve the changing of several gears inside the clock movement,
>which would in all probability, cost much more than you paid for the
>replacement.

>Hope this helps.

>Murray, Calgary

Not true:

A fix that will give you a few inches is this:
If the bob (disk at the end of the pendulum) is a solid disk, you can
replace it with a disk plate (light in weight) and add led weight to
the top (lengthens the "pendulum space") or add weight to the botom
(shortons the pendum, what you need to do.). Just be sure not to add
more weight than the original pendulum bob weighs.

Good luck.

PRB

Ron Schorr

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Jan 2, 1997, 3:00:00 AM1/2/97

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Dan Lurie wrote:
> I need to shorten the pendulum of a newly purchased Grandfather clock
> movement, to fit in a shorter "Grandmother" case; about 6 inches. Is
> there some adjustment in the movement to allow the shorter pendulum to
> oscillate more slowly?

If you're stuck with the movement and can't exchange it for the correct
one, there's still some hope (make sure you can get a new pendulum rod
if this doesn't work).

Shorten the rod to the desired length. Add weight to the rod near the
upper end. This will be above the center of osscillation and will have
the effect of "lengthening" the rod. If this doesn't slow the clock
down enough you can rig up an extension of the rod upward, above the
hanger the more weight you put at the end of the extension, the slower
the clock will run. This is called a compound pendulum. You can look
it up in a horological dictionary to understand the concept. You will
have to try to keep any added parts in line with the pendulum rod to
prevent the bob from wobbling.