Can anyone point me to a websight or book that will help me determine the length of a Pendulum for a particular type of movement.
I am assuming that if an escape wheel had 60 teeth on it I would need a pendulum that had a period of of 1 second from left to right and 1 second back right to left. I also assume that the longer the pendulum the heaver the bob needs to be. Some where I saw the formula for determining the length of a Pendulum to determing its period. But I can not find it.
Thanks Bob B

There is a discussion about counting the time train to determine the length of a pendulum in the book, "The Best of J. E. Coleman: Clockmaker", compiled and edited by George R. Hagans, American Watchmakers Institute Press, 1979. A cursory glance leaves me with the impression that a lot of counting, multiplying, and dividing is required. It is necessary to determine how many revolutions of the escape wheel are required to turn the center post one revolution and work from that.

Hi Bob...if you are able to use an Excel spreadsheet, my clock Work area has a worksheet with the formulas built in. You just count the teeth and pinions and it computes BPH and pendulum length. BUT, realize this is "theoretical" pendulum length; a rod with no weight and pendulum mass at a point. It will get you close enough that adjustments can begin. Here is the link to the sheet. Although some cells are locked, there is no password, so you are able to make changes.

Bill

http://www.clockguru.com/Photos/clockworksheet.xls

HERE is a link to an earlier discussion on pendulum lengths.

John. Thanks for the direction of the book.

Bill. Thank you for the spreadsheet it is the cats meow! I also enjoyed your websight and clock collection.

Tom. I was betting this was not the first time the subject of pendulumswas brought up. Thanks for putting up the link.

I thank you all again.
Bob B

the formula for calculating the length of a pendulum is as follows.

length = the square of the period of oscillation x 32.17/9.86

to determine the period of oscillation you need to count the train of the clock. this is done by adding the total number of teeth in all the wheels, and dividing by the total number of leaves in all the pinions. the teeth in the escape wheel must be counted twice otherwise you will end up with an incorrect count. once this is done you will know the number of beats per hourand can thus determine the number of seconds per beat, or the period of oscillation

I hope this is of some assistance. of course i am sure that someone out there can provide a clearer understanding of the principle than i have.