Reply To: Waltham pocket watch runs slow

[Bob Tascione]

Good question William.

Yes Curb pins, Index pins and Regulator Pins are all used to describe them. One may be more correct than another. I’m not sure. I think ‘Index’ was used in the U.K., Regulator in the U.S. and Curb? – maybe had something to do with the original ‘compensation curb’ but just guessing and most likely wrong.

When correcting this problem it’s important to figure out what caused the hairspring to move away from one pin in the first place. It could be that the pins have been moved and just need to be brought back into position. Most often I find that the hairspring has been bent at the stud and one simple bend will take care of the problem. By returning the hairspring back to it’s original position the spring should remain centered between the pins for the entire swing of the regulator arm. There are times that a double bend is needed at the stud. Example: assume that the hairspring is resting on the inside pin and we’ve determined that the problem is at the stud end and not the collet end. After making a single bend we find that it is centered between the pins but when the regulator is moved the spring again moves away from center. Making another small bend near the first bend in the opposite direction will often line things back up. These 2 bends will usually be all that’s necessary to make it right but…the problem doesn’t always originate from the stud but may be at the collet end. If the spring has been knocked off center at the collet then the adjustment must be made near the pinning point at the collet. Also if the hairspring has been knocked off plane then it must be brought back to level before making any adjustments.

On many watches the stud has no accurate locating mechanism so when the stud is removed from the balance cock and then replaced (like when replacing a staff)it may be twisted a little one way or the other. Twisting the stud a tiny bit back to where it needs to be will often bring things back to center. If not then a small bend or two will usually do the job.

If the spring has an overcoil then it’s possible that the coil was messed with but I don’t find this a common occurrence. Problem usually is at either end of the spring.

If the problem is traced back and found then usually just one bend is all it takes since one bend is normally all it took to knock it out alignment. If the stud didn’t relocate perfectly after removing from the balance cock then 1 to 2 bends at the stud pinning point is all it will take if the spring is correctly centered at the collet. Chasing the problem by adding more bends never worked for me.

Hope this makes sense and I didn’t confuse you William.
Please let me know.
Enjoy!
Bob