Help to fix balance for tissot 2571

[richiesgr]

Hi 

I'm trying to restore a tissot seastar 1970-1980. The movement is a tissot 2571 .

The balance have a problem but I don't know how to work on this balance. 

1. I don't know how to move the stud of the hairspring it seems to be a screw but it not. I try delicately with a twizer but it's very tight now of course if I force I'll deform the hairspring
2. This stud with the screw seem to set the center of the hairspring but I don't understand how to set it a the right position.
3. The hairspring is not plan in fact he is twisted and touch the arm of the balance

I join some pictures

Thanks  for any help

[richiesgr]

Hi 

So Is there eventually someone who know how to call this kind of balance it's not etachron type

I'm a little bit confused about this balance as it's the first time I saw this one 

Thanks 

[AndyGSi]

So how do the coils look when it's removed from the movement and are
the pivots OK as it looks to be sitting at an angle in the movement?

[richiesgr]

Hi

the pivot are ok no problem at all 

When I remove the balance from the movement I can see a deviation on the horizontal plan so the coil is not plan. 

The main question is how to remove the balance from the bridge ?

Thanks  

[caseback]

My guess (!) is that the screw slot is not there for aesthetic purposes.  I'd take out the balance complete, open/turn the regulator pins to give the hairspring room, hold the stud using the screw slot and turn the balance cock 90 degrees.

Edited November 27, 2024 by caseback

[TibiV]

Hello, I'm very curios how did you solve this problem because I have the same issue !

[Neverenoughwatches]

A picture from the underside would be good . Without seeing i would say the slot in the top of the stud is to adjust the concentricity of the hairspring like an etachron feature...the hairspring is glued or more likely clamped into the metal of the stud. Does the stud clip in from the side of beat adjustment arm ?

[Nucejoe]

 This one can be sorted out when in place ,without removing any part, a perfect concentric spiral is difficult to attain though, when sorting in place.

 There is no need to detach this stud from hairspring , just push  out the stud from the fork of stud holder. And if they are glued, dissolve in acetone, or apply heat to the stud with a soldering Iron. 

Good luck

 

 

 

[richiesgr]

19 hours ago, caseback said:

My guess (!) is that the screw slot is not there for aesthetic purposes.  I'd take out the balance complete, open/turn the regulator pins to give the hairspring room, hold the stud using the screw slot and turn the balance cock 90 degrees.

Not at all the hairspring is attached to it turning the screw will impact the coil geometry

[Razz]

You don't need to adjust the screw on the stud in most cases. The movement has an adjustable stud for beat error and then the rate can be adjusted but to adjust the pins you have to do that manually as there is not a way to do that. It has an incabloc shock system so no reason to take off the hairspring for a standard cleaning and oiling service, correct?

[Neverenoughwatches]

3 hours ago, Razz said:

You don't need to adjust the screw on the stud in most cases. The movement has an adjustable stud for beat error and then the rate can be adjusted but to adjust the pins you have to do that manually as there is not a way to do that. It has an incabloc shock system so no reason to take off the hairspring for a standard cleaning and oiling service, correct?

Eyup Razz matey. I think the Op is looking to flatten out the coning of the hairspring, this could just be some magnetic effects from the steel parts located around the balance cock.

On 11/28/2024 at 10:58 AM, richiesgr said:

Not at all the hairspring is attached to it turning the screw will impact the coil geometry

I would suggest demagnetising the balance assembly and cock first before detaching the balance.