Hairspring help - how do I make corrections to overcoil?

[mikepilk]

My least favourite task is trying to correct hairsprings, especially overcoils ... and my next project has that problem.

I'm putting together a Universal cal 267 and found the hairspring distorted. I've got it looking fairly flat, and not too bad 'in the round'.

The problem is the overcoil. The stud is too high, and I end up with coned coils when it's mounted.

To get the overcoil parallel, I need to start by bending down at 'A', and then probably another correction half way to the stud.

How do I make up/down bends on an overcoil? Is it by using two pairs of tweezers and twisting, as you would fix a twist in the main spring.
In which case, how do you do it without messing up the coils below?

Or do you just grasp it and make a vertical bend - is this possible ?

 

[Nucejoe]

Surely you agree, bending and unbending lowers fatigue threshold, in simple terms some moleculare bonds in the structure brake, such deformities would be the weaker length of the moleculare chain. In simpler terms you weaken h/s structurally as you bend and unbend, furthuremore you would be shortening the functioning length of the h/s as you raise the overcoil bend. 

A longer stud, if you be willing to consider it, solves the problem you are facing,   without creating new ones.

[praezis]

I rarely see Breguet coils that were not distorted...

You must twist opposite of the highest point, using 2 tweezers: there is a good chance that A is the right place. The stud should not go much lower (maybe a bit) else it may touch the spring "dial up".
The coil in the regulator pins area must be concentric, looks different here.
I also suspect, the whole curve after the knee is a bit too far outwards.

Frank

[mikepilk]

1 hour ago, praezis said:

I rarely see Breguet coils that were not distorted...

You must twist opposite of the highest point, using 2 tweezers: there is a good chance that A is the right place. The stud should not go much lower (maybe a bit) else it may touch the spring "dial up".
The coil in the regulator pins area must be concentric, looks different here.
I also suspect, the whole curve after the knee is a bit too far outwards.

Frank

I find twisting using two tweezers difficult - two pairs of tweezers, enough magnification and light all in the same area!

I can do it with the tweezer tips  on a hard surface, but how do you do it in the middle of the overcoil - tweezers just hovering in the air?

I can do a slight bend down at the elbow as I can just push the tweezer tips outside the last coil.

I agree that the coil does need bending in a bit, and I'll shape it to the regulator pins. 

 

[Nucejoe]

You have done a fine job so far, perfectly level nicely concentric . I add the palm of my hand to my tools.

The palm of your hand is equipped with feel and capable of outperforming other surfaces ,  gives you perfect access to the piece, variable angle of attack. takes part in numerous operations ....advantages are too many to mention. All you got to do is accept it as tool and get used to it, it will do wonders. The h/s will be contaminated and would need to take a bath in lighter fluid,  but shaped just as you want it. 

This spring is very easy to work on.