AS1130 balance cock won’t seat…

[tonydagee]

Hello chaps,

any help gratefully received with this one, I am at the end of my rope!

carefully cleaned and lubricated this movement from a NOS watch (very dry).

well, the  balance cock won’t seat without firm pressure( I tried it in alone after stripping the movement.)

surely it should drop in with a dead fit?

The balance does spin weakly or with a good strong blow,but how should I proceed from here?

don’t want to screw up the pivots obviously !

[mikepilk]

Balance cocks don't just 'drop in' but are usually a firm fit. You could open the holes a touch with a smoothing broach if it's too tight.

BTW the hairspring doesn't look right in the top pic.

 

[AndyGSi]

2 hours ago, tonydagee said:

well, the  balance cock won’t seat without firm pressure( I tried it in alone after stripping the movement.)

So did it fit OK at this point?

As @mikepilk said the hairspring isn't right and have you done anything with the top jewel as the screws look obliterated?

[mikepilk]

You say NOS, it must be quite old as it doesn't have Incabloc. I have one with Incabloc and moveable stud holder.

[nevenbekriev]

On You picture the hairspring is resting on the second wheel, but it must go under the wheel. You must be a complete newbie if can't see things like that. This is the problem - put it on place and lets hope it is not distorted. The hairspring must be free and not touching anything.

[tonydagee]

Hi nevenbekriev

Yes, my mistake… jumped the gun to get the pic in a hurry

but even correctly placed it won’t seat. And yes, I do know about proper placement 

.thanks for the observation

T

Hi AndyGsi,

I cleaned and oiled the non shock jewel and reassembled 

No issues there. But ,yes, the hairspring doesn’t look right….

even though the cock not seated, the balance does want to spin so the pivots are on the edge of the jewel holes.I’ll tinker some more…

 

[nevenbekriev]

Sometimes the pins of the cocks and bridges fix them pretty tight on the plate. If You are afraid to break the pivots when putting the cock in place, then it will be OK to slightly enlarge the holes where the pins go. Use a cutting broach. Be careful, no wobble of the cock  is acceptable, just ease the assembly. Of course, the cock must lie completely on the plate. It will be good to remove the balance when checking the effect of holes enlarging. Then, if still balance doesn't move free, You should check the axial free play. If all the parts are from this movement, then no reason to have issue there. If it is all OK, then concentrate on the hairspring. Show pictures here.

Edited August 1, 2024 by nevenbekriev