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Clock running slow help

pigsy10

Registered User
Sep 3, 2020
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Wales, UK
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Hi all,
Wonder if anyone could help please.
The mantle clock I have acquired is running about 5 minutes a day too slow. Otherwise it ticks away nicely.
The pendulum is wound to its highest position.
I attach some relevant photos.

I know it will need a good clean, but
Will adding weight to the bob make any difference?
Has it the wrong suspension spring?

Any help would be appreciated.

1.jpg 6.jpg PXL_20210125_150133997.jpg
 

Thomas Sanguigni

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Aug 22, 2018
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The escape wheel teeth sure look dirty, and you can bet your springs are too. Most likely, you are battling dirt. Forcing it to run may cause excess wear. I'd get it clean to start with. In the long run, you will be happier.
 
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R. Croswell

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Apr 4, 2006
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It is possible that you have the wrong pendulum but I agree with Thomas, you need to do a complete (disassemble including springs) cleaning and reevaluate before changing anything. After cleaning if it has a lively pendulum and is still slow you might add a spacer (some washers) between the rating nut and the pendulum disk. It is primarily the length, not the weight of the pendulum that controls the rate. When you have it apart you will likely find that it needs a few pivot hole bushings as well.

RC
 
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Dick Feldman

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Sep 1, 2000
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Contrary to popular opinion, cleaning your clock movement will probably have no effect on time keeping.
Within reason, a dirty clock will operate just fine if the movement is in good shape.
I do not advocate running a filthy movement but let’s look for a probable cause of the problem.
Cleaning is primarily a preventative measure and not curative.
That goes for oiling as well.
A clean, over oiled clock movement will probably make you feel better but not solve the slow running problem.
The speed of the hands is determined by the speed of the escape wheel which is determined by the length of the pendulum.
Are you are following another repair person who installed a (too) long suspension spring and gave up on the time keeping?
I would start by somehow shortening the pendulum length.
Best,
Dick .
 
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shutterbug

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One thing I notice is that the pendulum hanger is touching the front of the crutch. It should be centered .... but maybe it was in the case. I think I'm leaning toward a good cleaning as the first step too. Repair is often a process of elimination. Get rid of one potential issue and see what remains.
 
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pigsy10

Registered User
Sep 3, 2020
25
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Wales, UK
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A clean, over oiled clock movement will probably make you feel better but not solve the slow running problem.
The speed of the hands is determined by the speed of the escape wheel which is determined by the length of the pendulum.
Are you are following another repair person who installed a (too) long suspension spring and gave up on the time keeping?
I would start by somehow shortening the pendulum length.
Best,
Dick .
[/QUOTE]
Thanks,

I agree that maybe the suspension spring is too long.
I will try RC's suggestion and a shorter spring.

Thanks all for your suggestions.
 

JimmyOz

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Feb 21, 2008
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I would follow RC's suggestion, however, get a tube that will fit over the threaded shaft, file a small V shape in the end so the pendulum bob fits snug onto it as it looks neater.

The suspension spring setup looks correct and if you did make it shorter you will have difficulty getting the pendulum on.

If you have the skills to service it yourself go ahead, however, if not and the clock is working okay just leave it till it stops working and then get it repaired.
 
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shutterbug

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Yep. But usually the bob sits fairly low in these kinds of cases. This one is pretty high already and is still losing time.
Strange one.
 

Vernon

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Dec 9, 2006
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Zooming in on the ew., It looks like the teeth are mashed over. I'm with Thomas and others, you've got to get it properly cleaned and then you can see what problems exist.
 

pigsy10

Registered User
Sep 3, 2020
25
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Wales, UK
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Thanks every one for your suggestions.

I have tried RC'S suggestion and also a different bob but the clock is still running slow.
Without a pendulum attached it gallops fast as it should.
I would really like to take the movement apart and clean it but as a newbie I am not cofident enough to do it.
Maybe I will start with a single train movement.
 

Willie X

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Feb 9, 2008
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Was the bob you tried smaller? A smaller bob will have a higher center of gravity, assuming the top edge can be placed at the same point that the larger bob's top edge was. 1/4" will make a huge rate change on a short pendulum clock.

Many clocks like yours had a small plain cast iron or lead weight. Also, mantel clocks don't usually have that type of suspension spring/rod arrangement. IOWs Mark may be right in his assessment.

Willie X
 

pigsy10

Registered User
Sep 3, 2020
25
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1
Wales, UK
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Was the bob you tried smaller? A smaller bob will have a higher center of gravity, assuming the top edge can be placed at the same point that the larger bob's top edge was. 1/4" will make a huge rate change on a short pendulum clock.

Many clocks like yours had a small plain cast iron or lead weight. Also, mantel clocks don't usually have that type of suspension spring/rod arrangement. IOWs Mark may be right in his assessment.

Willie X
Hi
The bob was about the same size but lighter.
Agree that the spring is usually shorter, but a shorter spring would need a longer leader ?
 

Willie X

Registered User
Feb 9, 2008
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A shortened suspension spring will raise the bob and make your clock go faster. Although it doesn't appear that your crutch position will allow the suspension spring to be much shorter. A shortened suspension spring will also be slightly stiffer. This will also make the rate faster.

There is a recent post that shows the type of pendulum found in many of these clocks. I will try to find it and post back.

Willie X
 

Willie X

Registered User
Feb 9, 2008
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Look at current "Haller movement" post #1. Imagine a similar pendulum with a shortened hook. Willie X
 
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