balance wheel freezes

[jdp020351]

Good evening group;

I recently purchase a 18s ASP pocket watch, gold filled. it ran great for a few weeks and has stopped running. i have not taken the watch apart yet to see what it might be. however when i removed the back i noticed that the balance wheel has great amplitude. The hair spring is in great condition. it appears to go faster and suddenly freezes (stops) dead. it does not slow down than stops but suddenly freezes. when touched, it will run than freeze. any thing that i might look for when i break it down?

thanking all in advance
Jerry

[dlgraley]

Any possibility it's intermittently making contact with the cock/bridge?

[jdp020351]

Thank You, I will check for that
Jerry

[Randy]

Hey Jerry
Dlgraley is spot on.

Just to add to his suggestion, see if it stops in only one position, Dial up or down, left or right, etc.
Dial up and I you would prove out his assessment that it's possibly riding on the balance cock.
Dial down...maybe a cracked balance jewel.
Any position and I would have to think that maybe it's a bad wheel tooth that hangs it up..or possibly the banking pins are missing, or need to be closed in a bit.

Lot's of different possibilities

Let us know if we can help in any way...

[jdp020351]

Hi Randy
I was thinking, could it be over banking? the balance wheel locks up and I have to use my peg wood to release it.
it does lock up in one position. (stem up and face tilted at 45 degrees) Broken jewel?
I'm stripping it down today and inspecting it.
I will let you know what I find.
Thanks to every one for their help
Jerry

[Randy]

It could be either of those issues Jerry..or even another one you will run across !
Before you strip it down, just remove the movement.
Then while it's running,..try your best to observe the balance as it runs in the various positions using a 4X or stronger loupe.
Look for the hairspring to rub on the balance wheel or against the cock.

You could have both issues going on at once..just try to isolate them one at a time

Best

Randy

[jdp020351]

will do Randy
Thank You
Jerry