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Does hacking stop the mainspring barrel?

Annapolis
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Just idle curiosity as I continue to teach myself about watch movements. I don’t usually post questions here—I know how to use google—but I’m having trouble landing on a solid answer for this one.

When you hack a movement—stopping the balance wheel—the mainspring continues to unwind, right? I feel like it has to—? It’s not like you could wind your watch up, then hack it and keep it powered up indefinitely. Or am I wrong about this?

Still nooby here, after many years, but learning.
 
Dan S
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There are several different types of hacking mechanisms, but commonly, a lever stops the balance from moving. In that case, I don't see how the mainspring would continue to unwind because the oscillation of the balance regulates the rate of power loss.
 
JimInOz
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As Dan indicated, once the escape wheel is stopped, all movement in the going train is static.

Screen Shot 2022-12-25 at 11.54.09.png
 
Annapolis
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Ok. This makes a lot more sense than the other possibilities I was imagining. So one could indeed wind up a watch and then hack it and keep the reserve.
 
josiahg52
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I thought it did and thanks to the display back on my Seamaster, I can confirm hacking the cal. 8800 stops the balance wheel so that tells me the mainspring would thusly be held in its present state indefinitely. This seems to be in line with the more knowledgeable folk here.
 
Archer
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Annapolis Annapolis
Just idle curiosity as I continue to teach myself about watch movements. I don’t usually post questions here—I know how to use google—but I’m having trouble landing on a solid answer for this one.

When you hack a movement—stopping the balance wheel—the mainspring continues to unwind, right? I feel like it has to—? It’s not like you could wind your watch up, then hack it and keep it powered up indefinitely. Or am I wrong about this?

Still nooby here, after many years, but learning.

You are wrong. Once the balance is hacked, it no longer releases the escapement, and the wheel train can’t move, so the spring stops unwinding.
 
Annapolis
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Understood, thanks all.

Car analogies never quite work, but I suppose I was wondering if it was a bit like slipping a car into neutral (disengaging the transmission from the differential) with the engine still running. But I can see now that this wouldn’t make much sense, what with the entire point of the escapement/balance being to the manage the release of stored energy from the mainspring.

I wonder, then, if there’s any potential harm in leaving a movement hacked for a prolonged period (I mean months or years). If it might degrade the mainspring to be kept in static stress like that, or somehow damage the efficacy of the hacking mechanism itself.

Again, just idle curiosity. I can’t really see any reason one would do this. Maybe to ease the setting/winding nuisance on a watch you don’t wear often?—just leave it wound from the last wearing, and keep the second hacked to 12, so all you need to do next time is set the time and go?…
 
Annapolis
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I do realize, of course, that this would leave the watch more vulnerable to moisture and dirt. I’m thinking in a dry, clean, protected environment, like a safe. …And I have no plans to do this.
 
wagudc
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I am no watchmaker, but the hack is designed for a particular use (stopping the movement briefly in order to set the watch precisely). Using the hack to save the energy stored in the spring is outside of the original design. From that point of view, what you suggest is ill advised
 
Canuck
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Applying the hack would in no way adversely affect the balance wheel (which the hack contacts when applied), the hack, the gear train, or the mainspring. The mainspring has a finite life expectancy whether the watch is stored with the spring partly wound and the hack applied, or with the mainspring completely run down. But as has been mentioned, the primary purpose of the hack is to enable the wearer to set the watch accurately to the second, a reference source.

Forget quartz watches, most of which still use battery power when the watch is hacked. Hacking most quartz watches to save battery life is futile.
 
Archer
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Annapolis Annapolis
I wonder, then, if there’s any potential harm in leaving a movement hacked for a prolonged period (I mean months or years). If it might degrade the mainspring to be kept in static stress like that, or somehow damage the efficacy of the hacking mechanism itself.

No real danger in it, but not sure why one would bother. If the crown system is designed properly (and the seals in good condition), then nothing is going to get inside the watch when you hack it.

On quartz, yes it can save a lot of energy in a modern quartz watch, but it is very much dependent on the movement. Older or very cheap movement just block the wheel train when you hack them, which can actually increase the battery consumption. Newer and better movements will disconnect the motor from the circuit, so only the circuit itself is running, which takes maybe 1/10th of the energy as when the watch is running, so it can extend battery life.
 
kohster
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Very interesting/informative about quartz watches. I was under the impression that hacking a quartz watch would indeed completely disconnect the battery. Another thing to add to the additional research pile. Thanks!
 
JimInOz
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kohster kohster
Very interesting/informative about quartz watches. I was under the impression that hacking a quartz watch would indeed completely disconnect the battery. Another thing to add to the additional research pile. Thanks!

To add further to the mysteries of "stopping the hands" on watches.


I've had quartz watches that "go to sleep" if the watch doesn't sense movement after a certain time. The rotor pulses are stopped (∴ the hands stop moving) but the timing circuit keeps ticking away.

When the watch is picked up, it senses movement and the circuit pulses the hands forward until it reaches the correct time.

Another example of energy saving
 
Men
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Nothing to add. Archer explained it perfectly. Anyhow there would not be a direct impact, putting away a winded watch in hacking position, for me it doesn’t feel right. Storing powerless means no force on any component. In hacking, full wind there is a continuing force in several components.
 
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