The balance wheel stops !

[AdrianNOGUES]

Hello,I dismantled an automatic mouvement that I took from a Sewor.

The problem is that when I reassemble it, everything is okay, I put on the balance wheel which spins, but when I screw the balance wheel bridge, tjr balance wheel stops.

The pivots aren't broken, the spiral looks okay...

I don't understand !!! Can someone please help me !

Thank You !

Post Scriptum : It worked before I dismantled it

Here is some pictures :

[Nucejoe]

Shim the cock.

End stones are pushing on pivot.

[Cmmb8519]

Did you re-assemble the end pivot stones in the right position? check if one (or both) are upside down?

If not, might be that the handshake is to tight. If that is the case, under the balance cock just make a small scratch in the metal (making the balance cock a micro thicker) to marginally increase the space for the pivot between the jewels. This will allow the balance to rotate more freely. This is not something you would need to do often and only on very old movements, so it might be just the stones that are not er-assembled right. 

[AdrianNOGUES]

Shim the cock.
End stones are pushing on pivot.

The only position where the cock doesn't block the balance wheel is when the cock isnt fully put, but once he's well put the balance stops. Sorry if I doesnt understood what you said, I'm french

[AdrianNOGUES]

Did you re-assemble the end pivot stones in the right position? check if one (or both) are upside down?
If not, might be that the handshake is to tight. If that is the case, under the balance cock just make a small scratch in the metal (making the balance cock a micro thicker) to marginally increase the space for the pivot between the jewels. This will allow the balance to rotate more freely. This is not something you would need to do often and only on very old movements, so it might be just the stones that are not er-assembled right. 

I didn't disassembled the end pivot stones ! So the problem isn't from there ! I will keep your idea of making a small scratch in the metal in a corner of my head, thank you.

[AdrianNOGUES]

I forgot to say that the balance wheel doesn't spin correctly, as if a pivot was broken. When I screw the cock, the balance wheel is flat but it doesnt spin.

[Cmmb8519]

Any of the pivot jewels with signs of being broken?

 

[watchweasol]

Hi As a starter do what Nucejo suggested and fit a shim under the balance cock. For example a dial washer or aluminium foil   just to increase the endshake on the balance staff.  What appears to be the problem is lack of endshake.

[AdrianNOGUES]

Any of the pivot jewels with signs of being broken?
 

No the movement is almost new !

[AdrianNOGUES]

Hi As a starter do what Nucejo suggested and fit a shim under the balance cock. For example a dial washer or aluminium foil   just to increase the endshake on the balance staff.  What appears to be the problem is lack of endshake.

Okay ! Thank you !

[Nucejoe]

You showed the cock and balance assembly in second picture, that is when you had the chance to visually inspect if both pivots are intact and undamaged.

If lower and upper pivots are both undamaged and balance stops as you tighten cock screw, then end stones are pushing on pivots.

You can guage but shimming is prefered as it is not destructive. 

Place a piece of thin aluminum foil under the cock, to raise the cock.

There is a slight chance of bent pivot.

[AdrianNOGUES]

You showed the cock and balance assembly in second picture, that is when you had the chance to visually inspect if both pivots are intact and undamaged.
If lower and upper pivots are both undamaged and balance stops as you tighten cock screw, then end stones are pushing on pivots.
You can guage but shimming is prefered as it is not destructive. 
Place a piece of thin aluminum foil under the cock, to raise the cock.
There is a slight chance of bent pivot.

Okay, Thank you very much !

[Michael]

If it is a new movement, nothing is damaged, it might be you have not tightened the balance cock screw tight enough 

[saswatch88]

11 hours ago, AdrianNOGUES said:

No the movement is almost new !

Just because it is almost new you could have done something during the service....did you take the balance out properly? Did you you check balance staff under very high magnification? Did you peg the jewels and Possibly push them out of position? Did you reattach the hairspring to the regulator stud properly that is if you removed it from the cock during service? I would agree with shimming the balance cock but this should rarely need to be done on a fairly new movement. I would put money on a cracked jewel/bent staff ( which could happen if you seated the balance wrong when you screwed it down)  also you should check the pallet action make sure it snaps back and forth before putting in the balance issue could lie there too. Also pallet and or Impulse jewel could have gotten loose during cleaning, esp if you used IPA for long periods.

[AdrianNOGUES]

Here is a better picture of the balance wheel.
I looked on the internet and some balance wheel doesnt have a thin pivot on the top and some have.
So I'm asking myself is this one broken ? It would be logic. Sorry for all the people I contradicted, and thank you for your help.

[JohnR725]

what was the running condition of the watch like before you've serviced service it

[AdrianNOGUES]

what was the running condition of the watch like before you've serviced service it

+33s/d, 204 of amplitude, 0.0ms beat error

[JohnR725]

1 minute ago, AdrianNOGUES said:

+33s/d, 204 of amplitude, 0.0ms beat error

the reason for asking the question is if I was running before it should be running again and you shouldn't have to put shims under the balance wheel that correct for I have no idea what?

then your first picture was taken at the wrong angle as it's really hard for me to see what I think I'm seeing? It almost looks like the balance bridge is not down all the way it's up a little on the right-hand side? you should make sure the balance bridge is down tight and parallel and that the balance wheel can still spin before you put the screw in

 

[jdm]

54 minutes ago, JohnR725 said:

the reason for asking the question is if I was running before it should be running again and you shouldn't have to put shims under the balance wheel that correct for I have no idea what?

Absolutely. I was surprised to see that this kind of advice given promptly when the practice is generally frowned upon.

[AdrianNOGUES]

the reason for asking the question is if I was running before it should be running again and you shouldn't have to put shims under the balance wheel that correct for I have no idea what?
then your first picture was taken at the wrong angle as it's really hard for me to see what I think I'm seeing? It almost looks like the balance bridge is not down all the way it's up a little on the right-hand side? you should make sure the balance bridge is down tight and parallel and that the balance wheel can still spin before you put the screw in
 

I agree with you ! Thats why for me the aluminum foil etc etc is the last thing I want to do ! For me I need to solve the problem, not avoid it !
On the picture, you're right, the cock wasn't down all the way because it was the only position where it allowed the balance wheel to spin, it was straight though (not one side more engaged than the other)

[AdrianNOGUES]

Absolutely. I was surprised to see that this kind of advice given promptly when the practice is generally frowned upon.

Me too, it's not a good solution when you know that after you, watchmaker will have to solve the problem, the only thing it does is avoiding it to make it much important later

[Michael]

Your photo is not that clear, but unfortunately it looks like you have lost your top pivot. It should be the same as the bottom pivot.

[AdrianNOGUES]

Your photo is not that clear, but unfortunately it looks like you have lost your top pivot. It should be the same as the bottom pivot.

Ok... sad but thank you for your help

[jdm]

17 minutes ago, Michael said:

Your photo is not that clear, but unfortunately it looks like you have lost your top pivot. It should be the same as the bottom pivot.

Indeed, well spotted. 

[watchweasol]

Hi    The fitting of a shim is NOT a fix its a diagnostic aid in as much as to slightly increase the end shake of the balance when trying to determine the problem, and once proved on way or the other, then removed and look to rectifying the problem.   I have had watches where the end shake was adjusted by digging a divot in the plate there fore raising the the balance cock and increasing the endshake also had them with shims in to do the same both left as a permanent fix    Not reccomended.