Expert: John Newman - 10/24/2009

Question
Good Morning John,

I have the privilege of resetting the time on a clock made in 1974 by my deceased best friend. I inherited this hand made Grandfather clock last year and just now able to getting setting it right!

I had a local "clock specialist" come in and check it out, clean, lube and reset the movement(s.) But the clock runs too fast and the Lyre pendulum disc is all the way to the end of the rod. In digging through the literature my friend left inside the clock I found a small note from Mason & Sullivan that indicates there is an ornamental "weight" to be added at the tip of the pendulum. No where do I find this weight.

The movement identification from the Mason & Sullivan order form receipt says the movement is a TU240, Whittier Tubular Chime Grandfather Movement. It also indicates the LP75 Lyre Pendulum was included. But "No Bob" is randomly noted on the front across the receipt as if my friend did the note. No where else in the information packet is the bob mentioned by him. I am assuming the "no bob" meant the weight at the end of the Lyre pendulum.

Being a machinist and machine builder for the last forty years I can probably fabricate one but it sure would be nice if someone knew the weight of this item. Or better yet there would be a bob weight available. I would appreciate any guidance on this predicament you might provide.

Answer
Max, the pendulum disc is what we call the bob.  I am not familiar with the ornamental weight mentioned by Mason and Sullivan.  I have some of their old catalogs and can find no reference to this item.  But in determining the problem it would help to know how much time it is gaining. Say the clock is gaining 5 minutes.  The time period has to be noted, such as 5 minutes an hour, a day, etc.  And would your friend have mentioned that the clock always ran fast?  There are a few causes of this.  One is that as the clock runs the escape mechanism is skipping teeth.  Technically, there are 2 pawls that rock back and forth allowing the escape wheel to step one tooth at a time.  If the teeth are damaged or worn, or the pawls are too high, skipping will occur.  An experienced clockmaker could make this repair or adjustment.  Another cause is that the suspension spring is too thick, thus reducing the amplitude of the swing of the pendulum for a faster oscillation.  The third is that the distance from the top of the pendulum to the bob is too short.  You have already correctly identified this in that the bob is all the way to the bottom and can be lengthened no more.  There are a couple of ways to correct this.  The first is to extend the top strap of the pendulum.  First, let me say that there are a few different types of pendulums between manufacturers, and since you did not have the manufacturer or their model number of the movement, I am not sure of the pendulum hanging configuration.  So the following is for one type, but you can modify it to suit your pendulum.  Being a machinist, you would probably have no trouble doing this.  Here is how I modify a pendulum.  Run the rating nut (the small round nut at the bottom of the bob) to the center of the adjustment.  Then make a temporary strap extender out of a piece of wire, forming it like a thin "U".  Make it abut 3" long.  Form the two upper ends as a hook.  Hook the wire extender on the hanger (the strap from which the pendulum normally hangs) and attach the pendulum to the bottom of the wire.  Run the clock for a couple of hours, using a reference such as a quartz watch or clock with a second hand.  Note the error.  If it is to fast, make a longer extender.  If it is too slow, shorten it.  When you have the time fairly accurate, measure the distance from the bottom of the hanger to the hook on the pendulum.  This is the amount that you would want to extend your pendulum strap.  If the top hook of the pendulum is riveted, you can grind off the rivets and install a splice to extend it.  Some of the models have a pendulum top strap/hook as one piece.  It has to be cut and spliced.  Once you have it completed, start the clock and use the rating nut to make the fine adjustment.  One other method I use is to pour lead shot or BB's into the bottom of the bob.  This will slow the rate.  Don't use shot that is too small as it would possibly run out of some of the bottom spaces in the bob.  When I do this on a customer's clock, I have a way of covering the shot with glue so when it falls to the bottom it will not run out the top when laid down, like for moving.  If you want to do this, first get back with me and I'll be glad to give you the steps to do this.  You don't want to end up gluing the mechanism so it won't adjust.

John Newman
THE VILLAGE CLOCKSMITH
Old Prattvillage
Prattville, Alabama