I'm working on an ETA 1100/Wyler WM29. The upper balance jewel has no shock protector and is held in place by two screws underneath. To remove these screws, for cleaning and lubrication of the jewel, what tool is needed to hold the balance down and spread the hairspring coil enough to work with a screwdriver? Is there a reference book that covers this technique?

Wouldn't you remove the hairspring first? Maybe I'm not understanding the question.

Thank you for your response. All that I am trying to accomplish is a cleaning of the jewels and balance. If I can remove the cap jewel without removing the hairsping from the balance assembly, I would do so. Are you advising to remove the hairspring in this situation?

Hi Tom,

You must remove the balance complete for cleaning, the balance assembly is extremely delicate. I always dedicate a section/cleaning basket just for this when cleaning. If you distort the hairspring slightly your watch will never run correctly and take a great deal of skill to make corrections. I cannot stress the importance of taking the utmost care with this part.

Thank you. So now I'm back to my tool question. When you want to remove the hairspring from the balance,do you secure it in the upside-down position for work? If so, how? I am familiar with the balance tack or scaffold for use with the hairspring down. What do you use to hold the the hairspring up and away from the cock?

Tom,

I cannot see why you would want to hold it upside down for work, if there is any reason you need to get to the bottom of the cock remove the balance complete. if you forget to oil the cap jewels never be tempted to try and sneak in with oiler/ auto oiler as you WILL get it on the hairspring or distort the hairspring in doing so, the less disturbance to the hiarspring the better.

Tom,,

You probably refer to some tool showed on the i. e. Bergeon catalog that is used to hold the balance cock up while you adjust the hairspring collar when setting the balance for correct beat.

The fact is that the procedure you are after does not allow other methods than disinstalling the hairspring stud from the balance cock and than proceed to any work on it.

Incidentally unless you have specific reasons , broken jewels etc. you do not need to remove the jewels to oil them.

rgds

You may not need to remove the jewels to oil them. You do need to remove the jewels to clean them.

Frank,

can you pls describe the correct procedure to clean the jewels after removal ?
tnks rgds

Enzo

You can peg them out, put them in the ultrasonic, or both.