The Little Balance That Couldn't.

[fjseal]

I have reassembled a Standard 96-4 movement, and it all seems ok, the hairspring doesn't look bad and is cleaned. However, the watch runs, but not very confidently and the rate changes in different positions. Also, it does not start when it is wound until I move the balance wheel.

Does anyone have any ideas, or is it likely to be a hairspring problem.

 

Regards,

Frank.

[Geo]

I would have a close look at the jewels for cracks or chips and check the hairspring for concentric it and flatness.

[frenchie]

I would have a close look at the jewels for cracks or chips and check the hairspring for concentric it and flatness.

+1

[matabog]

Not starting without an external impulse makes me think about the pallets and the escapement wheel...

[matabog]

Check if it has enough 'throw'. The pallets should 'snap' when you help it a little with a clean oiler. Also check the train of wheels moves freely - try blowing air on the escape wheel.

Edited April 20, 2015 by matabog

[Marc]

Is it in beat?

significant beat error will cause rate deviations in positions and require a kick to get it going.

It can also result in a less than confident oscillation.

[fjseal]

Thanks for the tips. Am away for a few days, so will look closer when I get back.

 

Frank.

[anilv]

Hi Frank,

 

Did it run before? How was the shape of the main spring? Did you give the barrel a wind before fitting the pallet fork to see if it really ran down all the way? A movement which was not properly cleaned or has 'issues' will wind down and stop but when you nudge the escape wheel a bit, it will run for a bit longer... this will happen a few times before it is really wound down.

 

If it ran before did you mess with hairspring stud? (the bit where the end of the hairspring fits)... as Marc said, this will affect the running of the watch..

 

 

Do this....

 

...with the movement out of the case you should be able to see the barrel teeth along the edge of the movement. Use a pegwood sharpened to a screwdriver shape, help the barrel along its path.. just some light presure..not really a push. If this helps and the watch runs more ' confidently" (love the term BTW) then you may need a new mainspring. Using a lot of pressure here will almost guarantee it will get galloping no matter what the issuing is but is not really helpful in making a diagnosis.

 

Anil

Edited April 20, 2015 by anilv