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Replacement Hairspring - Options?


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I am struggling to replace the balance complete (or hairspring) on a very rare and inaccessible movement, a Tudor caliber 2461. The movement, balance, and balance staff are all in excellent condition. The hairspring is not - it's broken. 

My first instinct was to order a replacement balance complete. Unfortunately it's not an easy one to come by. 

My second idea was to buy donor movements with compatible specs (Hamilton 678, 679, 692, etc) - KIF shock system, 18000 beat rate, and one fixed regulation arm. Still waiting on delivery of some I purchased. 

My third idea is to simply try to buy a hairspring to spec. Is there a way to buy complete hairsprings (wound, with collet, and stud)? 

Thanks! 

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 Dr ranfft lists a host of calibers of the same generation/family to 2461, those balance completes that beat the same would fit your watch( your best bet) and springs off of them would have the same springness ( CGS) therefore compatable with the balance you have. 

 Dedicated hairsprings as you speak of with stud and collet attached which all you got to do is to install existed for many calibers and might be found specially on ebay. 

Another point is Tudor expectedly used specifically high grade hairsprings. 

Regs

Joe

 

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Posted (edited)
1 hour ago, Nucejoe said:

 Dr ranfft lists a host of calibers of the same generation/family to 2461, those balance completes that beat the same would fit your watch( your best bet) and springs off of them would have the same springness ( CGS) therefore compatable with the balance you have. 

 Dedicated hairsprings as you speak of with stud and collet attached which all you got to do is to install existed for many calibers and might be found specially on ebay. 

Another point is Tudor expectedly used specifically high grade hairsprings. 

Regs

Joe

 

Thanks! 
I flip between the Jules Borel caliber reference and Ranfft to figure out what parts and movements are compatible. 
The harder part is finding similarly high grade donor watches without high price tags. 
A couple follow up questions: 

Is there an easy or consistent way to determine the collet size by movement type/caliber, manufacturer, or some detail like shock system? I need a .6mm collet size. 
I’ve been eyeing up Hamilton’s as potential good donors. Can you think of others you’d recommend targeting? 
Also to your point about beat rates, if I found a different family of calibers that beat at the same rate, could I harvest springs from them? For example, ETA 1080’s? 

Edited by mzinski
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Posted (edited)
1 hour ago, mzinski said:

Also to your point about beat rates, if I found a different family of calibers that beat at the same rate, could I harvest springs from them? For example, ETA 1080’s?

I wouldn’t choose a balance complete from an ETA 1080 since it has a different base caliber.
My curiosity of why I have so many balances completes for ETA 2390 at home got answered with this question too, it seems to fit a TUDOR Cal. 2461 too.
A quick search in the BestFit database confirms my suspicions.
So if you want to try a balance complete out for this one I would try the 2390 one or some in that family. (Note the difference in the roller table)

 

ROL TUDOR 2461.png

Edited by HSL
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Replacing hairsprings is really difficult due to finding the correct spring. I have a draw full of hairsprings purchased over the years but rarely find one that is suitable. 

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There you are, as advised above , same beat doesn't neccessarily mean neither  interchangability, compatibility nor incompatibility, 1080 hairspring might not/ might have same CGS as 2390, if you are lucky its CGS might be close enough to vibrate with 2390 balance. Even between members of same family its the same CGS which means compatible but not neccessarily interchangable right away.

2 hours ago, mzinski said:

 

Is there an easy or consistent way to determine the collet size by movement type/caliber, manufacturer, or some detail like shock system? I need a .6mm collet size. 
 

Go by staff, see what staff its suppose to fit on or has come off of. 

Any hairspring will eventually vibrate with a balance so compatibility is limited by the space available on the balance wheel. There are also factors such as stability of the beat, impulse energy .... but that is a designers concern I think.

I summary any of calibers Dr ranfft says no difference is known between them and 2461, would fit right into your watch.

I doubt if hamilton's hairspring grade meets Tudors standards, but what do I know. ?

 Good luck pal.

 

 

 

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9 hours ago, clockboy said:

Replacing hairsprings is really difficult due to finding the correct spring. I have a draw full of hairsprings purchased over the years but rarely find one that is suitable.

10 hours ago, Nucejoe said:

There you are, as advised above , same beat doesn't neccessarily mean neither  interchangability, compatibility nor incompatibility,

the problem is manufacturing tolerances of balance wheels. Traditionally every single hairspring is vibrated to a specific balance wheel. Exceptions to the rule are hairsprings that are manufactured first to very exacting specifications. Typically these are over coil hairsprings, the over coil has to be formed exacting locations. Then the balance wheel is matched by adjusting the timing screws.

Simplistic traditionally is two identical watches swap they hairspring is and it won't keep time because are not manufactured to close enough tolerances for that to occur. At least until relatively modern times perhaps.

References are interesting? Like the first link for different balance wheels when I figured out which one everyone thinks it is time to go with that whether it's right or not. Then look at the balance staffs think the balance wheels are confusing look at all the different staffs good we don't have to worry about that but that does appear to be a lot of variations.

But seeing as how the group seems to think that? Okay group likes 2390 but it looks like the base model at the link below is 2451?

so for the first link click on the right balance complete correspondence and 2390 scroll down to the bottom of the list almost andlooks like the available at the third link a bargain price. I suppose you could find one of the other balance completes and yes they would be cheaper but. Why go with cheaper when there it is.

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=TUD_2461

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=[^[DYE\

https://www.jewelerssupplies.com/rolex-tudor-2402-balance-complete-2402.721.html

 

 

 

Rolex tutor balance completes lots of them.JPG

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37 minutes ago, JohnR725 said:

the problem is manufacturing tolerances of balance wheels. Traditionally every single hairspring is vibrated to a specific balance wheel. Exceptions to the rule are hairsprings that are manufactured first to very exacting specifications. Typically these are over coil hairsprings, the over coil has to be formed exacting locations. Then the balance wheel is matched by adjusting the timing screws.

Simplistic traditionally is two identical watches swap they hairspring is and it won't keep time because are not manufactured to close enough tolerances for that to occur. At least until relatively modern times perhaps.

References are interesting? Like the first link for different balance wheels when I figured out which one everyone thinks it is time to go with that whether it's right or not. Then look at the balance staffs think the balance wheels are confusing look at all the different staffs good we don't have to worry about that but that does appear to be a lot of variations.

But seeing as how the group seems to think that? Okay group likes 2390 but it looks like the base model at the link below is 2451?

so for the first link click on the right balance complete correspondence and 2390 scroll down to the bottom of the list almost andlooks like the available at the third link a bargain price. I suppose you could find one of the other balance completes and yes they would be cheaper but. Why go with cheaper when there it is.

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=TUD_2461

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=[^[DYE\

https://www.jewelerssupplies.com/rolex-tudor-2402-balance-complete-2402.721.html

 

 

 

Rolex tutor balance completes lots of them.JPG

Thanks John! I was going down the route of the 2402, arriving at donor watches and thinking about eta 1080’s. But the link to a complete balance for $250 is a very good price - it’s been ordered. 

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I can happily report I received the balance complete from Cas-Ker today - all ready installed and running better than ever. Glad I got turned on to their availability rather than seek out a compatible hairspring or balance complete from a donor movement. 

IMG_7813.thumb.jpg.08c6742fb7b224571305732a2a8be43a.jpg

(for anyone paying attention, the dial was refinished by Bill & Sons in the UK)

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