Curb pin adjustment

[JohnC]

Hi folks,

Sometimes I come across watches with bent curb pins. For example, often the pins are pushed together on old pocket watches, or pins are bent out of shape for one reason or another. Can people share best practices for adjusting them? Are there any specialized tools for this? Many thanks.

[Graziano]

HI JohnC, on a pocket watch with 2 pins, remove the balance cock but with the hairpin stud intact. Turn the balance wheel together with the cock over; hold the cock & the balance up & use a thin sharp pointed blade [ similar to a scalpel ] to slightly open the pins enough to clear the hairspring thickness. The reason for the pins set towards one another is to prevent the hairspring from being dislodged. If a watch has two regulating pins they should be parallel, not bent towards each other. Generally the spacing between them is about 1.5 to 2 times the thickness of the hairspring. The spring is not "captured" but should be centered between the pins with no power to the watch. At normal amplitude the spring will bounce from one pin to the other. This is true also with the single pin and guard, the spring should be bouncing between the two when amplitude is "normal"

On wrist watches what I do is if the single pin is bent I use flat tweezers and ever so gently straighten the pin but I don't move in any direction. Chances are it will snap. Once the pin is straight as in no bends in it, I then proceed to nudge it in the direction needed, from about the middle of the pin. You really only have one shot at this on a wristwatch as the pin snaps at the base very easily. Anyway that's what I do. I haven't seen any tools specifically for the job but I use hairspring manipulating tools to push the pin. 

Hope this helps 

Graziano 

[oldhippy]

Remember not all pins should be open the Breguet balance spring for example. 

[nickelsilver]

You want the pins straight, and parallel, with a gap approximately equal to two spring thicknesses. The gap is a guide, you might want it closer, for example an overcoil would like a very small gap (just free) as OH said. Depending on how the pins are installed and their spacing. One some older pieces they are spaced a bit, so you have to bend them toward each other, then straighten. I just use fine tweezers for this, like #5. Sometimes to widen the gap a little those are still too big, then I will use a broken oiler that has been stoned to a very fine wedge shape (like a microscopic screwdriver). That will fit in the smallest gap and allow some tweaking.

[JohnC]

Thanks guys. I guess my concern with moving brass pins outward is using a steel implement on the inside, where the hairspring will bounce. I try not to touch the bottom inside of the curb pin, where the hairspring will make contact, as I don't want to bruise the pin and cause the hairspring to not bounce off cleanly. Anyway, all your suggestions are helpful. I will try the sharpened oiler trick.