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AdamC

New mainspring and Knocking

Question

Hi all,

 

I wonder if you can give any advice. I’ve just completed an unbranded watch from (I think) the 1920’s era (photos to give you an idea). As you can see, the original mainspring is of the old carbon steel type. Being an unidentifiable movement, I calculated the appropriate length using a mainspring calculator and then measured the other dimensions. The thickness/strength of the old spring is 0.11mm. As such I ordered a new S shaped white alloy unbreakable spring of the same thickness. After completing the rebuild, I noticed the galloping sound of the ticking and immediately recognised it as knocking the banking as described in one of Mark’s videos. So my question is twofold:

 

1: is there a formula/general rule for allowing for stronger modern replacement springs?

 

2: is there anything I can do to fix it bar replacing the spring again?

 

The watch has an additional issue in that the setting lever stem end is worn and wasn’t fully engaging the recess to operate the the sliding pinion; i.e., on pushing in the crown, the setting lever jumped out of the stem recess. Rightly or wrongly, I put some dial washers under the lever on the opposite side, and when tightened down it appears to be giving enough pressure to stop it jumping out. Again, without caliber id, I’m unable to source a replacement.

 

Finally, if anyone recognises this early 10.5’’’ movement, I’d love to know. I have suspected an FHF but not sure. All train wheel bridges are separate (unlike those designed to look separate).

 

Thanks in advance for any advice,

Adam

 

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10 hours ago, Nucejoe said:

If heavier oil on pallet-escape teeth didn't reduce amplitude, I don't know of any trick that wouldn't be laughed at

 

11 hours ago, AdamC said:

2: is there anything I can do to fix it bar replacing the spring again?

11 hours ago, AdamC said:

1: is there a formula/general rule for allowing for stronger modern replacement springs?

there is a classic way to reduce amplitude on a watch action there is a couple of classic ways. I've seen currently one of the Swiss companies if you're having that problem they recommend heavier oil for the balance pivots like HP 1300. Then there is the other classic method the pallet fork pivots are never supposed oil try putting some HP oil on that. Between the two you should reduce the amplitude down a little bits.

Then as far as I know there's no formula to convert carbon steel mainsprings to the modern mainsprings. Somewhere in the universe there is another discussion group were within the last year somebody said its toll crap that modern Springs are stronger than the original blued steel Springs. But they're made out a different how always and stuff. It's always been my experience that the new Springs can be stronger or different. A lot of times I have really interesting back curves that the original ever had. So because we don't have the proper tools you can't test the original spring to know what its strength was an you don't know how to compare it to the new spring. So you basically assume the new Springs are stronger and always go with a weaker spring.

That anything resembling calculations for mainsprings are problematic because they don't take into account how much energy is actually needed to run the various escapement's. Or if you a seven jewel watch versus a 17 jewel watch there is less friction but does the mainspring calculation take that into account? Plus even just the escapement designs the modern watches are more efficient than the old so any calculation you have is going to be an approximation anyway.

then there is the other approach when I was in school the instructor I had said give it a couple of days to settle down. That occasionally works and not sure how or why it works but given a couple of days and see if it gets better all by itself. Which is a very strange approach but in some cases it does seem to work which is basically do nothing.

 

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A few bits of advice from my experiences with the same issue:

Sometimes you can gauge how much the new spring is too strong if you can get it to run in a position where the amplitude drops (eg. crown down). Or perhaps it runs ok on a lower level of wind, eg. up until 3/4 wound. Although the torque follows the thickness by a cube rule, I’d say you are more likely to be successful by dropping to 0.10 if it very easily starts to bank. You are already getting what is in effect probably more than 360 degrees of amplitude.....

I would not alter the temper of the spring to deliberately cause it to set as this is not the same as having a set spring which remains at the correct temper. 

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As for differences in strength between steel and modern alloys, there are a few things to consider.

 

Elgin was the first to offer a modern alloy as a mainspring, Elgiloy, which is still used extensively in industry. Others followed, and nowadays we have most new springs coming from Generale Ressorts. They offer springs in two grades, stainless, or Nivaflex.

 

There are a few properties that one would look for in a spring, first being "springiness" or strength, which boils down to Young's Modulus. Another would be durability, and another ease of manufacture.

 

To see the differences of the common mainspring materials we have:

Carbon steel- Young's modulus of 206, fairly durable

Stainless steel- Young's modulus of around 190, quite durable

Elgiloy- Young's modulus of 211, very durable

Nivaflex- Young's modulus 221, very durable

 

While Elgiloy is still used in industrial applications I don't think anyone is making watch mainsprings from it anymore. One of its particular qualities is that its point of plastic deformation is very good compared to other similar alloys. So you can have a spring that can be pushed further without deforming or breaking- no doubt one reason it was such a good mainspring.

 

I don't think anyone makes carbon steel watch springs anymore, nor have for some time.

 

Nivaflex is the #1 choice of manufacturers for new pieces. As seen above, it is significantly stronger than carbon steel, and even more so than stainless. I have noticed that replacing a carbon steel spring with a stainless spring of the same thickness is indeed a step back in power. Likewise, replacing a carbon steel or stainless spring with Nivaflex offers a boost in power. I order directly from GR, and always request Nivaflex specifically. In some cases if they only have stainless in stock I will look elsewhere for old stock.

 

Bottom line is Nivaflex is stronger than carbon steel, stainless is weaker (as springs). Stainless springs will not have the reverse curve at the hook end like Nivaflex does, it will open up like a regular steel spring.

Edited by nickelsilver

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If heavier oil on pallet-escape teeth didn't reduce amplitude, I don't know of any trick that wouldn't be laughed at.

Here is one home made approach on which discussions are not welcomed.

Cover the spring with ash, mild heat over night by charcoil underneath, this will soften the spring somewhat.

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1 hour ago, AdamC said:

Hi all,

 

I wonder if you can give any advice. I’ve just completed an unbranded watch from (I think) the 1920’s era (photos to give you an idea). As you can see, the original mainspring is of the old carbon steel type. Being an unidentifiable movement, I calculated the appropriate length using a mainspring calculator and then measured the other dimensions. The thickness/strength of the old spring is 0.11mm. As such I ordered a new S shaped white alloy unbreakable spring of the same thickness. After completing the rebuild, I noticed the galloping sound of the ticking and immediately recognised it as knocking the banking as described in one of Mark’s videos. So my question is twofold:

 

1: is there a formula/general rule for allowing for stronger modern replacement springs?

 

2: is there anything I can do to fix it bar replacing the spring again?

 

The watch has an additional issue in that the setting lever stem end is worn and wasn’t fully engaging the recess to operate the the sliding pinion; i.e., on pushing in the crown, the setting lever jumped out of the stem recess. Rightly or wrongly, I put some dial washers under the lever on the opposite side, and when tightened down it appears to be giving enough pressure to stop it jumping out. Again, without caliber id, I’m unable to source a replacement.

 

Finally, if anyone recognises this early 10.5’’’ movement, I’d love to know. I have suspected an FHF but not sure. All train wheel bridges are separate (unlike those designed to look separate).

 

Thanks in advance for any advice,

Adam

 

1aa17e7339c8920cf8eb54d3569869a4.jpg&key=f4c451857d253ea7389fcff7a13982c15a6639d40c6c3cc17d24da064c02765d

 

8a39c51ed8ff84e280300c6571bff4b0.jpg&key=940f3dbc8b19ab66bdbf737064e99afc66954b2cd8ef39fba784ccde78fbe590

 

2e6302cfd59e0ba76610be3a5ae72ae0.jpg&key=27eca3b6753d95acf8d499daa23bbc823ccf65583c7e21339353095bc44f6eae

 

 

Sent from my iPad using Tapatalk

Looks like ANCRE movements, some ancre are similar to ETA or AS, anyway.

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37 minutes ago, Nucejoe said:

If heavier oil on pallet-escape teeth didn't reduce amplitude, I don't know of any trick that wouldn't be laughed at.

Here is one home made approach on which discussions are not welcomed.

Cover the spring with ash, mild heat over night by charcoil underneath, this will soften the spring somewhat.

oh, oil on fork pivots too.

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2 hours ago, JohnR725 said:

Somewhere in the universe there is another discussion group were within the last year somebody said its toll crap that modern Springs are stronger than the original blued steel Springs. But they're made out a different how always and stuff. It's always been my experience that the new Springs can be stronger or different.

Really interesting discussion John. I have come across this site, which gives a lot of information on mainsprings and calculators etc. Could be where you remember seeing where they consider old and new type springs are of equal strength (scroll right to the bottom of the page for that comparison). I think first, I'll take your advice and leave the watch ticking for a couple more days and see if it improves. Then as you a Nucejoe have mentioned, I may just put a drop of oil on the pallet fork pivot jewels, and I have HP 1300 oil too!

Edited by AdamC

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I'll probably get laughed in the same way as @Nucejoe *, but here's a brain wave:

The problem is a spring that's too strong, and the only REAL fix is a weaker spring. If you don't want to buy a weaker spring, why not weaken the one you have? When springs get older, the deform and get weaker, right? Take that S-shape and force it into a coil. You've got a bum spring, and the worst that can happen is you have a slightly bummer spring. 

*I actually really want to know why that works... Is it adding more carbon to the spring? Ash is a high pH, is it chemically doing something? Is it just an insulator to slow the heating and all that's really happening is altering the temper? You can't throw out that sort of left field magic without some sort of explanation!

Edited by spectre6000

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The technique might be useful in cases a better replacement is not available. 

The ash is to minmize availability of ambiant oxygen to the metal, therefore oxidation and subsequent rusting plus uniform distribution of the low temp heat imparted to the metal.

Heat is the kenetic energy of the constituent parts, Intermoleculare distance increase with heat ( thermal expansion) , any temp increase is an excitation of the phase the metal was in, though not neccessarily pass a chemical threshold level, it would affect the crystaline structure of the steel that is the crystaline formation of molecules undergoes some alteration depending on the de-excitation process, if not quenched "a rapid tem decrease" some bonds go un-reformed, therefore less intermolecular bonds , which amounts to less the springness. 

This is a crudely reversed mimic of metalurgical methods used in steel production.

 

 

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1 hour ago, spectre6000 said:

I'll probably get laughed in the same way as @Nucejoe *, but here's a brain wave:

The problem is a spring that's too strong, and the only REAL fix is a weaker spring. If you don't want to buy a weaker spring, why not weaken the one you have? When springs get older, the deform and get weaker, right? Take that S-shape and force it into a coil. You've got a bum spring, and the worst that can happen is you have a slightly bummer spring. 

*I actually really want to know why that works... Is it adding more carbon to the spring? Ash is a high pH, is it chemically doing something? Is it just an insulator to slow the heating and all that's really happening is altering the temper? You can't throw out that sort of left field magic without some sort of explanation!

I see you have a good understanding of metalurgy, the method is a crude ( home made) use of heat to reverse hardening.

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You're too kind... My great grandfather would be proud. Back around WWII, he had a high school education, and I'm told he made specialty alloys "by feel". He knew what properties different metals imbued, in what quantities, and in what combinations, and could whip up small batches of whatever you needed in a hurry with a high degree of accuracy and success. He spent many years swinging a ten pound sledge, and my dad says his right arm was noticeably bigger than his left. My metallurgical experience is limited to having made a pair of  marking sets (woodworking) from old mill files. 

Is there any way, beyond an acquired "feel" to gauge how hot/long to soften by how much? Alternatively, is there a minimum by which one could incrementally work their way to the desired amount of softening? A max to avoid?

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7 hours ago, praezis said:

what is the inner diameter of your barrel?

Frank

Hi Frank,

The internal diameter of the barrel is 9.14mm. But then I measured the external diameter of the barrel arbor, original spring thickness, and calculated the length (not forgetting the height of course). The spring I fitted was 1.50 x .11 x 280 x 8.5. Looking at the reverse engineering on David Boettcher's webpage, going on barrel internal diameter alone, it appears that a 0.105 strength spring may have been more appropriate.

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58 minutes ago, nickelsilver said:

Nivaflex is the #1 choice of manufacturers for new pieces. As seen above, it is significantly stronger than carbon steel, and even more so than stainless. I have noticed that replacing a carbon steel spring with a stainless spring of the same thickness is indeed a step back in power. Likewise, replacing a carbon steel or stainless spring with Nivaflex offers a boost in power. I order directly from GR, and always request Nivaflex specifically. In some cases if they only have stainless in stock I will look elsewhere for old stock.

 

58 minutes ago, nickelsilver said:

Carbon steel- Young's modulus of 206, fairly durable

Stainless steel- Young's modulus of around 190, quite durable

Elgiloy- Young's modulus of 211, very durable

Nivaflex- Young's modulus 221, very durable

Nickelsilver, thank you very much for your full explanation on the types and strengths of mainspring. This is really interesting and I have often wondered what Nivaflex is so when I have a choice in future, I shall opt for that brand. This takes me back to one of my original questions now. Based on Young’s modulus, I wonder if it holds that a percentage can be calculated to drop down the strength when replacing a carbon steel spring with a Nivaflex? For example, it appears Nivaflex is 7.3% stronger, so in my case, 0.11/1.073=0.1025, so I’d replace my 0.11 carbon steel with a 0.10 or 0.105 using judgement (as @Rodabod mentioned) in this case as the calculation lies in between those springs available. Of course, I may be talking rubbish if Young’s can’t be used for this kind of physical science :)

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18 minutes ago, AdamC said:

 

Nickelsilver, thank you very much for your full explanation on the types and strengths of mainspring. This is really interesting and I have often wondered what Nivaflex is so when I have a choice in future, I shall opt for that brand. This takes me back to one of my original questions now. Based on Young’s modulus, I wonder if it holds that a percentage can be calculated to drop down the strength when replacing a carbon steel spring with a Nivaflex? For example, it appears Nivaflex is 7.3% stronger, so in my case, 0.11/1.073=0.1025, so I’d replace my 0.11 carbon steel with a 0.10 or 0.105 using judgement (as @Rodabod mentioned) in this case as the calculation lies in between those springs available. Of course, I may be talking rubbish if Young’s can’t be used for this kind of physical science :)

I'm not an engineer, but I think you can do it like that! At least it seems to correspond to practical experience.

 

 

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@AdamC 
considering age and possible wear of your movement, your choice of a slightly thicker spring is intelligible. For a more modern, less wear movement I 'd chosen 0.10 rather and is what my calculator recommends.

Nivarox/steel: strength changes in 3rd power with thickness, not linear. I suspect, needed decrease of thickness will be much less.

@nickelsilver
I buy from GR, too, but mostly the Inox variant. They have the same S-form as Nivarox springs. 

Frank

 

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considering age and possible wear of your movement, your choice of a slightly thicker spring is intelligible. For a more modern, less wear movement I 'd chosen 0.10 rather and is what my calculator recommends.


Thanks for your thoughts Frank. I’ve heard from some people that the mainspring strength should be less for older vintage watches due to using modern oils that reduce friction in the jewels compared to the old mineral oils used back in the day. I’m learning new stuff every day, helping me to master these interesting skills and become a better repairer/servicer.


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11 minutes ago, AdamC said:

I’ve heard from some people that the mainspring strength should be less for older vintage watches due to using modern oils that reduce friction in the jewels compared to the old mineral oils used back in the day.

I would regard this as nonsense, I am sorry.
Old neatsfoot oil (when fresh) had better lubricating properties than modern oil. 
But wear of teeth and bearings (if not jewelled) gives more loss in power transmission. Hence imho the opposite is true.

Frank

 

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Ok, I had to look it up:

Torque of the barrel M ~ E x I
  E= E or Young's modulus
  I= moment of inertia (with physical dimensions of spring, e.g. s^3)

Means, influence of E is direct (linear), influence of thickness s is with 3rd power.

My source (Prof. Glaser: Uhrentechnik) mentiones:
E, springsteel, texture rolled: 225
E, Inox: 190 - 210
E, Nivaflex: 225

About the same as above.

Frank

 

Edited by praezis

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Just to continue the point that Frank is describing, the thickness is your more likely issue here, as the difference between 0.11 and 0.10 is 10%...... and that difference is effectively cubed when it comes to calculating force. 
 

1 cubed = 1

1.1 cubed = 1.331

That’s an increase of 33%

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Thank you gentlemen. It’s been a really interesting discussion. I don’t remember where I heard about the old oil vs modern but it shows how you can accept these concepts without question sometimes if it sounds feasible (especially as a relative newbie at three years experience at this fantastic hobby)


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4 hours ago, AdamC said:

Thanks for your thoughts Frank. I’ve heard from some people that the mainspring strength should be less for older vintage watches due to using modern oils that reduce friction in the jewels compared to the old mineral oils used back in the day

a couple of minor problems with this. Mineral oils are still available so they haven't gone away we could conceivably still use them or are still using them. then organic or animal-based oils  as the reference am currently looking at calls them were supposed to be much better than the mineral oils.

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12 hours ago, praezis said:

Old neatsfoot oil (when fresh) had better lubricating properties than modern oil. 

Do you have specs for this? Since this thread has gotten into the numbers, I figured it was worth an ask. The thing that strikes me as a major shortcoming of neatsfoot oil is the fact that it oxidizes/polymerizes. The push in modern oils is toward longer service intervals, and I'm not aware of neatsfoot oil as being more lubricious than synthetics, while the synthetics are typically petroleum based and less susceptible to oxidation. Full disclosure, my experience with neatsfoot and petroleum based oils are in entirely different domains.

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