Newbie Question about long drop vs short drop

[john]

One more of my famous newbie questions. I have a sessions short drop school house clock I am trying to restore. I picked up some used movements , cleaned and installed one. I can not slow down the speeding time. The bob is all the way at the bottom and it still is running fast. Could there be a difference in short drop and long drop pendulums ? I assume there is, so how can I tell the difference when viewing the movement. This is a time only sessions movement. Thanks in advance .

[Bob Tascione]

Hi John,
I’ve held off answering your post in hopes that someone up here knew of a quick way to determine pendulum length for Sessions. Short of calculating the train I can’t think of any way other than the lazy way I do it. When in doubt I usually just hang different length pendulums and check the timer until I get close. There may be a quicker way like different escape wheel teeth count. Maybe someone here has the answer or has a few Sessions movements laying around they can check.
Sorry I couldn’t offer more help John.

Bob

[john]

Bob, thanks for the reply. I guess a timer will be one of the items for my wish list. I have tried counting the drive train teeth, and then trying to apply the formula for each gear…. I think the timer will be the best way to go. thanks…

[Bob Tascione]

Hey sorry John…that’s a typo on my part. Didn’t mean “timer” but rather “time”. I just let it run for a while and check to see if it’s keeping time. If it’s real slow or fast over a period of time I then make an extreme adjustment and keep track of the change. Then make one or two more adjustments and can usually get close fairly fast. Again…I’m pretty lazy. The best way is just to do a train count but then I have to think!
Bob

[john]

Bob, thank you . You answered my question and now with the clarification of timer and time, you just saved me a few hundred dollars ha ha. I like this solution the best as far as just track if its running fast or slow. Thank you.

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