Running clock with no pendulum.

Kevin W.

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I was just wondering , if you run a clock for a long time with no pendulum, could this eventually damage the escape wheel or pallets?
 

Richard T.

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I don't think so. Why would anyone wish to do this? :confused: If a movement is being tested it should be done with the pendulum on.

Best,

Richard T.
 

Kevin W.

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I am asking only as i heard of someone doing this, say for a day or more and they and i were not sure if it could cause the problem i mentioned.I advised the person i did not think it was good to do this for a long time.
Thanks for the reply Richard.
 

shutterbug

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Faster impulsing, no doubt, but with near zero impact from weight I wouldn't think it would have a huge affect in the short term. If you let it run that way for a month, maybe ..... but overnight I don't see an issue.
 

Thyme

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Faster impulsing, no doubt, but with near zero impact from weight I wouldn't think it would have a huge affect in the short term. If you let it run that way for a month, maybe ..... but overnight I don't see an issue.
Agreed, overnight won't harm anything. I sometimes do it as a test to check for anything bent; it's useful for discerning any lack of power through the train, and checking EW & verge problems.
 

Willie X

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It would have to run for a long time to do any damage. Actually there could be less contact forces without a pendulum in play. But ... I can't think of any reason why anyone would want to run a clock without a pendulum. Most people find the clacking noise very annoying.

Willie X
 

shutterbug

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Ver,

It would have to run for a long time to do any damage. Actually there could be less contact forces without a pendulum in play. But ... I can't think of any reason why anyone would want to run a clock without a pendulum. Most people find the clacking noise very annoying.

Willie X
For timing purposes, it shortens the "hours" by a bunch and hurries things along when counting BPH. It also speeds up the 'break in' period some clocks need after bushing work. Otherwise, there's not many reasons to do it :)
 

FredWJensen

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You can speed up to check the operation of a three train weight movement this way.
Let it run for a day or two and you will notice that all three weights have dropped equally.
 

Tony Ambruso

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I have to agree with this practice to quicken the testing for BPH with a Microset. Also, I usually perform a short testing period on each clock after assembly without lubrication and without the pendulum to reveal any gross problems. If there are adjustments to be made that require the plates to be separated, I want to do so without lubricant travelling to undesired places. So I lubricate after I am fairly sure that I won't be separating the plates again. Ultimately, I test the clock with its pendulum.

The only damage that I'd say is caused by this is the wear and tear associated with normal use, which is increased because of the increased action of the movement. But this "normal wear and tear" is absolutely negligible over a brief period of time - even long periods of time. It's not like you are allowing the clock to "freewheel" [run without a verge or pallet].
 

Thyme

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I always do that. If you run it for 50 years like that it might need some bushing. ;)
I think Mike is "on the wrong side of fifty" chronologically (as I am too).

Hey Mike, which clock movement did you run with no pendulum for 50 years to test the theory? (Otherwise, skeptics may not be convinced... :rolleyes:):clap:
 

harold bain

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Thyme, I have a Smith's clock that has run for about 50 years without a pendulum (but I did bush it recently):D
 

Dave B

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I don't empirically "know" this, but I suspect 'freewheeling' causes extreme wear in the pivots which move the fastest (i.e. escape wheel arbor) not becaue of the increased speed of rotation, but because of heat generated within the pivot bearing, that destroys the lubricating qualities of the oil.. If a clock is allowed to run wihout the pendulum, though, the speed of rotation is still only a fraction of the speed with which a strike fly arbor moves under normal operation. I have rarely had to bush the strike fly arbor holes, so it stands to reason that there is no undue wear caused on the escape arbors by running with no pendulum.

Because the escape wheel teeth do not have to overcome any additional force of inertia, as they do when impulsing a pendulum, I would think the wear on the escape wheel and verge would actually be less than running with a pendulum. The verge arbor, however may be a different circumstance. Because it is only rotated back and forth over a small arc, and because it wants to move sideways at each reversal of motion (I am thinking of equal and opposite reactionary forces, combined with force of inertia), speeding up that reversal could conceivably apply additional sideways force on the pivots at each reversal, thus tending to oval the hole. I believe that is where the most additional wear would occur in the case of running without a pendulum.

Any mechaniwockle engineers out there? Perhaps you could weigh in on my theorizing. :)
 

shutterbug

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Your reasoning sounds plausible to me :) (but I'm not an engineer, just a wanna be)
 

Mike Phelan

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Dave
I'm not a muckanic of any sort, but here's my take on it, good or bad.


Pivot wear is almost certainly determined by these things:
  1. Hole and pivot materials
  2. Pressure on the pivot
  3. How many turns in a given time
  4. Diameter of the pivot
  5. Thickness of what it runs in
#1 is usually the same in a given clock
#5 is as well, except for barrels & covers.
#2 and #3 vary as to how far up or down the train is and contradict each other.

In a perfect world, #4 would decrease as you go up the train, but that's rarely so in mass-produced clocks.
In actual fact the pivot diameter doesn't change as much as it should in theory.
There are a few imponderables like initial lubrication and how good the depthing was.

No real answer, methinks!

Back to the question;
For starters, when I reassemble a clock, I leave all the striking and chiming levers off so these trains run from beginning to end.
I don't wind the going train fully, but leave the pallets off and just keep winding it a few clicks whenever I'm passing.

As to the escape wheel and pallet holes, it also depends on what sort of escapement it is.
 
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