Hairspring Issue Lemania 873

[Dico]

Hello All

 

Im working on regulating a Lemania 873 chrono which was fully serviced about 2 years ago. I have the beat to under 0.8ms, but the speed is erratic reading -400 plus and moving the regulator doesn’t do much. Despite the -400 reading the watch is running fast. I figure I have a Hairspring problem and noted the large loop in the photo between the beat and regulator levers. Does something look off here that needs to be corrected? Any help is greatly appreciated!

 

 

 

 

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[watchweasol]

Hi The balance spring should be concentric, that loop should not exist, there should be a smooth curve right up to the pinning point. You will have to manipulate the balance spring to achieve the smooth even curve then set about regulation,  For reference take a look at any other watch and observe the balance spring shape and operation so as to familiarise yourself as to what you have to acheive.

[jnash]

That's a new setup to me, I'd getting fast it may be because that hairspring is now too short

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[watchweasol]

J Nash is correct the bend in the spring has effectivly shortened its length there fore speeding the watch up. spring length effects rate. remove the bend back to the curve and proceed from there

[margolisd]

Oops. It looks to me like the regulator pins have moved past where the terminal curve starts. Then when attempting to move back into the terminal curve they have caught it and bent it badly. It's going to need some very careful unbending.

[Dico]

Thank you all very much for confirming, I figured it looked off. Any suggestions on the easiest way to pull the loop thru?


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[Nucejoe]

End section ( between stud holder and regulator pin) of hairspring is deformed. 

Possibly hairspring is grabbed in the slot of regulator arm.

Move regulator arm and stud apart, this would streigten the said section, you can try to give a shape.

Edited January 3, 2020 by Nucejoe
Move stud holder reg pin apart. Shape HS.

[margolisd]

This is useful...

 

[watchweasol]

Hi  you have been given two clear pictures of what to achieve, Probably best to remove the balance and spring, and take the spring off the balance. First check the balance rim for a mark denoting the stud position relative to the impulse roller, If no mark leave the spring on the balance and support the balance in a stake taking care to protect the roller, reform the balance spring as show in the pictures maintaining the flat profile once done mark the balance rim (marker pen fine) with a dot for future reference.  refit the balance to the cock and refit to movement  now start the regulation. Check the beat error as this is likley to be out   Lemania lift angle = 50. 

[watchweasol]

Hi  you have been given two clear pictures of what to achieve, Probably best to remove the balance and spring, and take the spring off the balance. First check the balance rim for a mark denoting the stud position relative to the impulse roller, If no mark leave the spring on the balance and support the balance in a stake taking care to protect the roller, reform the balance spring as show in the pictures maintaining the flat profile once done mark the balance rim (marker pen fine) with a dot for future reference.  refit the balance to the cock and refit to movement  now start the regulation. Check the beat error as this is likley to be out.  The lift angle for Lemania 1873 = 50. 

[Dico]

Thank you all again for the great feedback! I attempted to straighten the loop and the Hairspring completely detached from the collet. Is it possible to reattach this? Is it even worth it to use this same Hairspring given then deformation? Any suggestions on where I can source a new one if this one is not salvageable?



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[watchweasol]

Hi  for the sake of practise I should have a go at re curving the old one and if sucessfull  re pinning it to the cock and try it.   If it ends up knackered you have lost nothing. Sourcing another spring or balance complete cousins uk  or ebay for a donor movment depending on your location Esslinger , Jules Borel  in America or Perrins, Canada.  good luck  

[Dico]

Good advice I’m giving it a shot here to see if I can correct it. I’m working on straightening the curve first but I’m not sure how to reattach the Hairspring. Does this pin just pull out ?


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[margolisd]

Has the HS broken off from the stud? Is there a small length of HS still in the stud? Is so, if you reattach then the length will change. So regulating may be difficult. Plus the terminal curve will need adjusting so it’s between the regulating pins. It’s a tough repair. Dynamic poising may help correct for the too short HS. But to be honest, replacing the balance assembly might be easier. 

[rduckwor]

Yes, the HS is pinned to the stud with a tiny brass pin.  As others have noted, repinning the HS will effectively alter the length of the HS thus altering the timing of the escapement.  Its good practice, but you may not be able to regulate the movement following your efforts.  As I said though, good to know how to do this particular repair.  Good Luck,

RMD

[watchweasol]

Hi Dico   as mentioned  it is just pinned to the stud, press the pin out and remove the remainder of the broken spring. Stand the balance on the cock in the correct orientation and manipulate the spring end into the hole and re fit the pin just enough to hold it in place, adjust the outer curve so it sits between the regulator pins now re bit the balance. The first thing you will notice its now out of beat due to the re pinning , the roller and impulse jewel will be in the wrong place. If you can reposition the stud arm you may over come this a little , The rate of the watch will be fast because of the shorter spring but as this is purely for practise no matter. To return the watch to its former glory It will need either a new spring or balance complete (with spring attached and timed). but the lesson learned by re fitting will stand you in good stead when fittin the new balance..   Cheers

[Nucejoe]

Yes, just pull out the stud pin.

Normally you can still regulate if HS is shortened up to a mm or two. Just reshape the end curve reattach HS to the stud, repin or use glue.

Mobile stud carrier easily lets you keep impulse in beat.

Good luck

 

[Nucejoe]

This collet is not removable. It is fine where it is.

Judging from the picture, you hav'nt lost but a mm or two of the hairspring. Which is usually alright, just reshape and reattach the HS, it is regulatable.

[Dico]

Thank you all very much! I decided to get a new balance assembly as I couldn’t quite bend the terminal curve exactly uniform. Wasn’t easy to find but I was able to source one on eBay. Very helpful guidance from the members here very much appreciate the help!


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[Nucejoe]

20 minutes ago, Dico said:

Thank you all very much! I decided to get a new balance assembly as I couldn’t quite bend the terminal curve exactly uniform. Wasn’t easy to find but I was able to source one on eBay. Very helpful guidance from the members here very much appreciate the help!


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Have you checked prices,  Chrono grade balance is real expensive. 

[Dico]

Yeah about $320 US . This if the one I found


https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F112015850622



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[Nucejoe]

12 minutes ago, Dico said:

Yeah about $320 US . This if the one I found


htps://rover.ebay.com/rover/0/0/0?mpre=%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F112015850622



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The price implies Chrono, link dose not say.  I say lets leave it for the last resort.

I am pretty sure the balance you got would regulate just fine. True, a nicely uniform end curve is not only pretty but renders regulating easy , however not a neccesity for proper oscillation, in other words it dose not have an essential role.

As long as the curve is near concentric with other circles of the coil, you are Okay. Regulate first then get the inner coils concentric. I,ll be happy to work with you to get the thing running.  I can,t tell if this balance is a Chrono grade but it be a shame if it is  and you can fix it, but let it go to waste. 

Best wishes

[watchweasol]

Hi Dico  thats one pricey balance Joe's advice sounds good to me keep at it remenber if it gets a PIA walk away and calm the mind we are here to help

[Dico]

Man you guys are great! Ok I’m going to try and use the one I have and see how it regulates. So to remove that pin and get the Hairspring re-attached do I simply pull it with a tweezer or push it from the other side?


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[Nucejoe]

58 minutes ago, Dico said:

Man you guys are great! Ok I’m going to try and use the one I have and see how it regulates. So to remove that pin and get the Hairspring re-attached do I simply pull it with a tweezer or push it from the other side?


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I used to get the pin out like you said, then bought me a cheapy long nose pliers and made my life easy. If you are going to order one, let us show you a suitable one.