# Mechanical Pocket Watch - Causes Of Rapid Hours/minutes Hands Spinning



## Nitrous (Jan 12, 2013)

I saw a pocket watch speed up to the point that the hands (including the hour hand) were visibly spinning on the dial. In principle, anything which reduces the amplitude of the balance wheel (friction caused by dirt etc) will speed up the movement, right? But if the balance wheel stops, so too does the watch so there is a diminishing returns aspect to that argument.

Anyone think of a reason that the hands of a pocket watch would spin like that? If the watch was modified, would something as simple as limiting the amplitude of the balance wheel cause the watch to speed up? If so, to what extent?

Thanks for any thoughts on this, you might be able to share

Doug


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## tixntox (Jul 17, 2009)

A missing pallet or a broken pallet will allow the movement to spin freely rather than be caused to "tick and tock".

See the part under the white paper on this video:-






Mike


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## Nitrous (Jan 12, 2013)

tixntox said:


> A missing pallet or a broken pallet will allow the movement to spin freely rather than be caused to "tick and tock".
> 
> See the part under the white paper on this video:-
> 
> ...


Thanks Mike,

So, in a more controlled sense, would narrowing the pallet distance (likely not the correct term) cause the movement to speed up, but slow down again if the space were "normalized" again?

Doug


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## tixntox (Jul 17, 2009)

The only way the hands would spin round would be for the pallet to be missing the escapement, allowing the gearing to run down the spring.

Escapement Video

and Another

Mike


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## Nitrous (Jan 12, 2013)

tixntox said:


> The only way the hands would spin round would be for the pallet to be missing the escapement, allowing the gearing to run down the spring.
> 
> Escapement Video
> 
> ...


So, if the pallet block on the balance wheel were not there, the pallet fork would just move back and forth with no regulation, I that correct? What if you limited the excursion of the pallet fork? Would that have the effect of speeding the movement up?

I'm not quite sure how the balance wheel pallet block would result in a runaway watch. Does the balance wheel simply stop spinning? It seems, from the animation that there is a notch on the balance staff which allows the pallet fork to reverse direction. Otherwise, this movement seems to be blocked by the balance shaft.

Thanks for the video links. They're very illuminating. I appreciate them.

Doug


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## tixntox (Jul 17, 2009)

If the pallet is not there, the gears have nothing to stop them running the spring down. As you wind the watch, it would immediately start to run itself down with the hands spinning freely. I've seen this happen when someone has tried to clean a watch with a thinners, which melted the shellac that held the jewels on the pallet, allowing them to fall off!

Pallet jewels pic.

Pic for info only (not as mentioned above)

Mike


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## Nitrous (Jan 12, 2013)

tixntox said:


> If the pallet is not there, the gears have nothing to stop them running the spring down. As you wind the watch, it would immediately start to run itself down with the hands spinning freely. I've seen this happen when someone has tried to clean a watch with a thinners, which melted the shellac that held the jewels on the pallet, allowing them to fall off!
> 
> Pallet jewels pic.
> 
> ...


Thanks Mike,

This sounds rather like an all or nothing situation. I wonder if the balance wheel amplitude was severely restricted, wouldn't the effect be similar but more controlled. Ideas on how to limit balance wheel amplitude?

Doug


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## tixntox (Jul 17, 2009)

If you can imagine one "tick and tock" moving the second hand a fraction of a second and consider the number of "ticks and tocks" to move the minute hand quickly................... Wow!


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## Nitrous (Jan 12, 2013)

tixntox said:


> If you can imagine one "tick and tock" moving the second hand a fraction of a second and consider the number of "ticks and tocks" to move the minute hand quickly................... Wow!


Indeed. The whole think could self destruct in seconds. I imagine the pallet roller would be off the balance wheel if the thing gets going too quickly!

I'm beginning to think that maybe the balance wheel and escapement in general is destined to be out to the equation. Putting a vriable brake on the drive train probably makes more sense to explain the controllable rapid hand movement.

Thanks for clarifying this for me.

Doug


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