The Mechanical Clock Pendulum Assembly

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The Mechanical Clock Pendulum Assembly

The mechanical clock pendulum assembly does not mean just the pendulum alone.

The use of the word assembly means the pendulum consists of three components and not just the pendulum. A pendulum assembly consists of the suspension spring at the top, the leader that hangs on it, and then the pendulum.

Pendulum styles

Usually mechanical clock pendulum makers are not movement makers and the two are married together by a person or place. A place such as Clockworks or Howard Miller instead of the movement manufacturer. This is interesting because it explains why there can be so many variations in pendulums for one movement.

The pendulum could be a brass rod, wood stick, or metal lyre style.

Pendulum bob diameter size

To determine the bob diameter for a mechanical clock pendulum, need to consider what looks good as well as which one won't whack the sides of the case. A good rule for the bob diameter is it needs two inches on each side to swing.

So if the clock case is 12 inches wide the bob cannot be more than 10 inches. In this example we would need a 10 inch bob but these are not made.

So the choice is clear that for a 12 inch wide clock case the maximum bob size to get is 8 1/2 inches wide. If this rule did not exist and the 10 inch wide bob is run the clock may go tick, knock, tock, knock, as it hits the sides every time it swings. Eventually the clock will stop running from this resistance. Plus it is quite annoying to hear that sound!

Pendulum lengths for Mechanical Clock Pendulum Assembly

The length of the pendulum has to be correct for the gearing inside the movement. If the mechanical clock pendulum is too long the clock will be too slow. If the pendulum is too short the clock will run too fast. When a clock is too fast or slow it usually has nothing to do with the movement itself. It only has to do with the pendulum length alone and nothing else.

Pendulum top mount hook

The top hook has to hook to the leader on the movement. The leader is the part that holds the mechanical clock pendulum up in the air and it hooks to the suspension spring. Sometimes an old pendulum will not hook to the new movement the same way as it did on the old unit. However, this is not common. It may or may not need a new top hook for the pendulum.

Pendulum leader

The leader is the 3 to 7 inch long part that the mechanical clock pendulum hangs onto. The leader hangs onto the suspension spring which is on top of the movement. At the same time it will have the crutch on the back of the movement engaged with the center of the leader. The crutch is the wig wag part that is sticking out of the back of the movement.

To install the leader, remove the set screw on top of the suspension spring. With the suspension free it can hook onto the leader and be brought back up. The leader then goes onto the suspension and the crutch on the back of the movement at the same time. This assembly gets brought back up again to mount with the set screw like it was.

The content of this website is copyright by Clockworks and written by James Stoudenmire in year 2022

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Kim Franzen
Kim Franzen
1 month ago

My old clock from the 1890s runs fast. I have the bottom nut screwed down as far as it goes with out it falling off. The clock still runs fast is there something else I need to do to slow it down. This clock is an old shelf clock.

Seth Thomas
Seth Thomas
2 months ago

I just inherited a ST floor model with movement A451-002. When moving the pendulum leader fell off. Its a LEAD-H leader. I installed it with that little attached bracket facing toward the end of the shaft, as it seemed to mate up there. Is that correct, or should that bracket be toward the gear mechanism? Photo attached. I wish I could be more clear, but it’s my first look into one of these things. Thanks so much in advance for anything you can offer.

clockPendLeader .jpg
John L Rush
7 months ago

Sorry this will sound so dumb but I can not see how to hook up the pendulum on my grandfather click . my great aunt came home with it in the 50 after she was in Germany. Its never been moved since then and when my cousin passed away a few months ago I brought it to my home . I was careful as if it was a newborn baby but as I pulled the head of the click from the padded box I made to move it , the piece between the gear and the pendulam iitself fell off and I don’t remember how it hooked on. Any help would be great .

Larry Lousen
1 year ago

How does a bob attach to a wood pendulum?

Ivalou Zimmerman
Ivalou Zimmerman
2 years ago

we have a over 100 year old clock that needs service…i have been able to make it keep correct time but the gong only gongs once on the hour…. but when i was setting it it gonged once for every hour ex 10 gong,gong s at 10 oclock
I live in southwest OK and am looking for someone who is trained on such clocks pendulum and weighted movement.

our clock goes bong bong in two tones beautiful deep tones is a floor standing two bongs at one o clock a d 12 bong bongs at 12 oclock

6 months ago

There is a clock shop attached to wagon wheel restaurant in Ulysses, ks. A little old Mennonite man runs it. They have worked on several of our antique clocks/pocket watches and all are in great working condition now.

2 years ago

How dow the 3little nuts go on the bottom of my barwick clock #C10628

Patricia L Farwell
2 years ago

My pendulum will not swing any more.

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