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Discussion Starter #1
Hi all.

I am new, so regards to all good people here.

I am interesting about two things.

Why the gears of the time train are of different material then others? And which material is it?

Second about main spring and barrel. What controls, or how, the force of the spring to the escapement? If the spring has different power, how the force is constant on the time train?

Hope this is understandable question. I mean I was clear enough.

Best regards all.
 

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Discussion Starter #4
Nice. Thanks.

So, in the range of force when the spring is full till end, the force is irrelevant?

OK. What about materials?
 

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Why the gears of the time train are of different material then others? And which material is it?
Than other gears? Or other parts of the watch in general? From what I've read, wheels are mostly brass, and pinions steel, to keep the wear down on the fewer leaves of the pinions.

Second about main spring and barrel. What controls, or how, the force of the spring to the escapement? If the spring has different power, how the force is constant on the time train?
The torque on the train is not constant as the mainspring unwinds, unless the watch has a special mechanism (a fusee and chain, or a periodic defined torque transfer gizmo, as in the Lange 31) for it. So the balance amplitude will change with the winding state of the mainspring.

There are some interesting books and free electronic documents out there that will help with general questions. Freely available watch catalogues, like from Lange or IWC or Jaeger-LeCoultre, also contain some technical detail with nice pictures and drawings. See
TM 9-1575 – I Already Have a Watch. and [Catalog] All the watch catalog I've ever found on the internet : Watches
 

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Discussion Starter #6
Well, it is obvious that torque force is descending. I am not interesting in details, but when they start to project a watch, do they start with escape wheel and force needed on it or vice verse, what they have on the spring. I am just curious.
And to keep the wear down on the fewer leaves of the pinions is strange reason. ( English is not my mother tong, perhaps I do not understand this). Steel should last longer?
But thank you for kind explanation. I shall look on the links.
 

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The use of two different metals reduces the chances of binding and adhesion due to rust , electromagnetism , etc... . Also the Zinc in the brass almost acts as a lubricant (over simplified explanation).
 

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Yes it is relevant. Any modern watch will speed up as the mainspring winds down, this is due to less amplitude delivered to the hairspring/balance wheel per stroke as the spring winds down due to Hooke's law, making every 'beat' shorter, increasing the rate of the watch. You can measure the decrease in amplitude on a timegrapher, sometimes as much as 50 degrees. This is your 'isochronism' error quoted on your movement's specifications. However with modern mainspring materials like Nivarox and impulse pin design this isochronal error is usually less than 10 seconds a day in reality. There are of course attempts to allow constant force to be delivered by a mainspring that follows Hookes' law, like the Girad-Perregaux constant force escapement watch, but those cost about the same as a supercar.
Nice. Thanks.

So, in the range of force when the spring is full till end, the force is irrelevant?

OK. What about materials?
 

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If you were designing a watch, you'd probably start with the balance wheel and figure out how much force you need for the balance wheel to have a proper amplitude. This will be a function of the size and weight of the balance, which will require a certain size and strength of hairspring. The design, layout and tolerances of the escapement and gears will impose a loss of force that also has to be accounted for, so at the end of the process you'll need a particular mainspring to deliver the force required.
 

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Discussion Starter #10 (Edited)
Now it is little clearer to me.

So, if you would take, just for example, 7 day power reserve and limit just to use fourth day power, than the difference in power should be minimized. But I have a watch running one sec per day ahead. What happend with this? There must be something minimizing this difference or it is not so big (10 sec/day) Is adjusting the palet solving it? Or it is becouse selfwinding take it always (mostly) full wind? And "constant" power?
 

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For someone for whom English is a second language, (your English is fine by the way) you ask some great questions. One second would be considered excellent in any watch brand of mechanical watches. Pallets are adjusted to change amplitude not rate. Rate is adjusted by changing the "effective length" of the hairspring. We do this by moving the regulator pin or pins usually. Many things can affect the rate which is why we don't generally adjust the regulator until everything else that can affect the rate has been addressed.
I often have people ask me to adjust the rate on their watch. When I ask when they last had their watch "overhauled" and they say they can't remember, I tell them it is necessary to do the complete service or overhaul first. Cleanliness, mainspring wear, oil evaporation, greases turning to shellac and wear to pivots require attention before we can begin the delicate process of "regulating" a watch.
Almost all mechanical watches run best when fully wound. This is the main advantage of "automatic" winding watches as they are always kept fully wound. The purpose of the automatic winding system in not to wind the watch from empty as most people believe. Most often, testing a watch that has been thoroughly overhauled is done not only at full wind but at half wind as well. Most watches do not run as well at 1/2 wind as full wind but do run well enough to be considered acceptable. Watchmakers try to make the winding reserve irrelevant but it isn't possible to totally do so.

Your question as to how the power of the mainspring is released consistently and evenly is a big question in that it requires a big answer.
When one winds a spring and then releases the winder, one would expect the spring to instantly release it's power in a short time. Obviously when a watch is wound this doesn't happen. Something prevents the "unregulated discharge of power of the mainspring". That something is the "escape wheel" and the "pallet lever". The pallet lever acts as a switch, moving back and forth, allowing the escape wheel to rotate one tooth at a time. The escape wheel by the way is the final wheel in the gear train and the gear train is transmitting all the mainspring power to the escape wheel. So as the pallet lever switches back and forth, power is released from the mainspring through the train out the escape wheel. So, what causes the lever to move back and forth? The balance. The balance wheel "oscillates" or rotates back and forth. As it does so a jewel located on the bottom of the balance on a surface called the "roller" engages the end of the pallet lever with enough momentum to move the lever to one side thereby releasing mainspring power. As the balance oscillates back and forth, the lever is switched back and forth. This is as simple an answer I can give. My peers will hopefully forgive my simplicity and the gaping holes in the explanation. I didn't wish to overwhelm the questioner.

Keep the great questions coming!
 

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1. All mainsprings follow physics i.e. Hookes' law so the force delivered will decrease over time. This is inevitable unless you have a constant force escapement ($100,000).
2. Isochronism error however is kept to a minimum by 3 things,
-Escapements are freewheeling(free sprung balance), so they are kept separate from the gear train and are only connected through the impulse pin, which is programmed by changing the lift angle to deliver a relatively constant amplitude to the balance wheel per stroke. This minimises amplitude loss as the spring winds down.
-Many hairsprings these days have some sort of overcoil, absorbing any extra energy delivered. The whole point of an overcoil was to achieve perfect isochronism
-Mainsprings are never fully wound or fully unwound so most of the force delivered is the middle range, where a mainspring doesn't have that much of a deviation
 

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Discussion Starter #14
First of all, thank´s to all trying to help about my question.

I am not a layman, I am nescient about wathces. What could I conclude from your posts. The watches are in error becouse of spring, and this error is insoluble by cheep solutions today. And that is that. Perheps I should be sarcastic speaking about it, as in some posts.

Am I right? Should some give counterargument insted of LOL? Something obviously for someone is secret for other. That is why I came here, to try to undersand.

So, best wishes to all of you.
 

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-Many hairsprings these days have some sort of overcoil, absorbing any extra energy delivered. The whole point of an overcoil was to achieve perfect isochronism
I thought the overcoil was simply to prevent the hairspring from vibrating perpendicular to the plane of the coil?
 

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. . . . . . . -Many hairsprings these days have some sort of overcoil, absorbing any extra energy delivered. The whole point of an overcoil was to achieve perfect isochronism . . . . . .. .
Edited content, above.

I thought the overcoil was simply to prevent the hairspring from vibrating perpendicular to the plane of the coil?
Original content, below.
 

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. . . . . . However with modern mainspring materials like Nivarox and impulse pin design this isochronal error is usually less than 10 seconds a day in reality. . . . . .
How does an alloy such as Nivarox reduce isochronal error?

What is the specific modern variation in impulse pin design that reduces isochronal error?

. . . . . . . There are of course attempts to allow constant force to be delivered by a mainspring that follows Hookes' law, like the Girad-Perregaux constant force escapement watch, but those cost about the same as a supercar.
I have a fusee that I want to swap for a Lamborghini.

1. All mainsprings follow physics i.e. Hookes' law so the force delivered will decrease over time. . . . . . . .
New experimental ones made of alternate materials - not so much.

. . . . . 2. Isochronism error however is kept to a minimum by 3 things, -Escapements are freewheeling(free sprung balance), . . . .
How does a free sprung balance positively impact isochronism? [The positive influence to reducing positional delta via the removal of excessive gravitational interference of the hairspring with the curb pins while transiting the stem positions is obvious.]

. . . . . absorbing any extra energy delivered. . . . .
With regard to isochronism, why is this a positive. For example: If it is beneficial at maximum impulse, why isn't it also parasitic at lower impluse exaggerating the amplitude differential.
 

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With regard to isochronism, why is this a positive. For example: If it is beneficial at maximum impulse, why isn't it also parasitic at lower impluse exaggerating the amplitude differential.[/QUOTE]

I believe it is
 

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First of all, thank´s to all trying to help about my question.

I am not a layman, I am nescient about wathces. What could I conclude from your posts. The watches are in error becouse of spring, and this error is insoluble by cheep solutions today. And that is that. Perheps I should be sarcastic speaking about it, as in some posts.

Am I right? Should some give counterargument insted of LOL? Something obviously for someone is secret for other. That is why I came here, to try to undersand.

So, best wishes to all of you.
No secrets here. However, we do have posters that sometimes appear to be be "posers". They are not suffered well here.
 

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1. All mainsprings follow physics i.e. Hookes' law so the force delivered will decrease over time. This is inevitable unless you have a constant force escapement ($100,000).
2. Isochronism error however is kept to a minimum by 3 things,
-Escapements are freewheeling(free sprung balance), so they are kept separate from the gear train and are only connected through the impulse pin, which is programmed by changing the lift angle to deliver a relatively constant amplitude to the balance wheel per stroke. This minimises amplitude loss as the spring winds down.
-Many hairsprings these days have some sort of overcoil, absorbing any extra energy delivered. The whole point of an overcoil was to achieve perfect isochronism
-Mainsprings are never fully wound or fully unwound so most of the force delivered is the middle range, where a mainspring doesn't have that much of a deviation
Are not automatics always fully wound?
 
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