Breguet bonus

[Simeon]

I have an old Omega 26.5 SOB with a mangled hairspring. I got this as a non-runner from my father-in-law. I have located a balance complete for it but wanted to have a go at straightening out the hairspring first (so to speak). The overcoil was pulled out in a loop somehow between the stud and the regulator pins. I don't know all of the correct terminology for the parts of the hairspring and overcoil, so please bear with me. 

 

Here's how I intend to go about it:

1) Replace the cock back on top of the pivot and determine which of the main coils looks like it follows the arc of the regulator pins on the regulator arm above it.

2) Having determined which coil looks like the correct one, roughly adjust the terminal curve of the overcoil to follow this coil underneath, matching the curve. 

3) Remove the hairspring from the balance wheel, having marked the position of the collet in the staff. 

4) Install the hairspring stud into the upside down cock.

5) Check the position of the collet relative to the jewel hole, looking to have it centered. 

6) Adjust the angles where the overcoil comes off the main coils underneath and the terminal curve where it goes into the stud. Tweaking the curve and bends until I get the collet centered. 

7) Reinstall the hairspring on the balance staff and reinstall the balance complete on the cock. 

8 ) Reinstall the balance cock on the bare main plate and examine the hairspring in its installed position. Looking for the overcoil to at least not be touching anywhere and the main coils to look centered and even. 

I am a bit worried that some of these bends look too sharp and I will just snap the spring while trying to straighten them out . Any tips for this, or is it just in the lap of the Horology Gods?

The terminal curve is also quite twisted so will need to make lots of small twisting adjustments to try and get the spring perpendicular again. 

I have seen people use diagrams that show the layout of various types of hairspring. Any idea where I could get those and how I would determine which one suits my particular hairspring? I have De Carle's book on the way, so will have something to throw at the wall when the hairspring snaps. 

Not sure how successful I will be with this, I have saved a few flat hairsprings and got reasonable results with manipulation (including one that was probably as badly mangled by being pulled into a bunch) but never an overcoil - the 3rd dimension scares me a little. I have also irreparably damaged a few so I want to have a go at this before wiping out my watch budget by dropping $250 AUD on a NOS balance complete. 

 

[nevenbekriev]

OK, just shape the end of the overcoil like I have drawn with red. The shape of the beginning is correct and don't do anything there but (if needed) bringing it in plain which is parallel to the hairspring body. It depends on how many it has been bugled before, but seems like it will straighten with no problems.

 

Edited October 14, 2024 by nevenbekriev

[rehajm]

Yes, as mangled hairsprings go that one is in fairly good shape. Looking like it was bent by being pulled by the pins when the regulator was turned…

[Nucejoe]

 I didn't get the philosophy behind removing the overcoil off the balance.

 Lower coil should be and looks undisturbed, lets first take a look at its side view when on balance in the watch and out of the watch when detached from the cock.

 We can then determine the best approach to soring out the upper coil.

Rgds

 

 

[nevenbekriev]

Hi Joe, it actually depends on the person. I for example would not need to remove the spring from the balance. It is possible to straighten everything without that. Checking how the hairspring stays on the bridge without balance is good thing, especially for a newbie, but the presence of the balance doesn't make this check impossible, and even gives some more helpful information. But, removing/placing back the hairspring takes seconds and should be regular operation that no one should be frighten of. Sometimes it is more convenient to work on the spring when it is off the balance wheel, placed on glass and the glass placed on white parer.

[Simeon]

13 minutes ago, Nucejoe said:

 I didn't get the philosophy behind removing the overcoil off the balance.

 Lower coil should be and looks undisturbed, lets first take a look at its side view when on balance in the watch and out of the watch when detached from the cock.

 We can then determine the best approach to soring out the upper coil.

Rgds

 

 

I was only thinking that having the hairspring removed from the balance would improve access as I wouldn't need to pick my way over the balance wheel spokes plus let me see if the collet is centered on the jewel. 

I guess that isn't the case with an overcoil as it is (or should be) naturally above the balance plus forming the terminal curve and getting the shape right may be a little easier than thought. 

[nickelsilver]

One thing you can do if you remove the spring is to place it on the upturned cock, centering the collet over the jewel, and observe where the regulator pins are in relation to the coils. Now you can form the curve over that coil (or between two), sort of a built-in guide. When you're happy with the curve, most of the final adjustment should be right near the stud- and you can check this with the spring off as well.

[Nucejoe]

I totally rely on TG machine for BE adjustment.

 Deforming force was applied near the stud and adjust arm, so not much deformation is expected to have occured on lower coil.

Hello neven, please don't ask me how many overcoil I have destroyed to gain the dexterity to sort out overcoil in place and  have to agree with you, a newbie might be better off just seperating the hairspring.

Didn't know Simeon is a newbie, newbie working on overcoil ? A brave newbie.

Rgds

Edited October 14, 2024 by Nucejoe
correction

[Simeon]

Bit of an update. I have managed to get the hairspring into a reasonable shape. I managed to distort the spring right at the collet when initially taking it from the balance. It was really stuck in place and I ended up having to twist it off with a craft knife. My hand levers just wouldn't quite get underneath it and I slipped and bent the hairspring when levering it up. I nearly gave up at that point and ordered the new balance complete but I figured 'why not keep trying until you really mangle it?'

I held the collet down and stroked the hairspring where it came of the collet until I got it untwisted, laying flat and mostly central. I then layed it loosely on the upturned balance cock and had a look at the layout. It looked like the outer curve of the overcoil which runs through the regulating pins needed to be in line with where the next inner coil should be. I gripped the overcoil where the sharp bend needed to be and stroked it to the necessary angle. I then worked along the outer curve to get it where I wanted it. The stud had a further sharp bend but I wasn't sure whether that was required or not. At this point I tried placing it on the upturned balance cock with the stud in position. This showed me that I was far off and the curve needed to come right in over the next flat coil. Off it came again and I remade the sharp bend to bring the overcoil back closer to the centre.

First attempt 

This time, when I installed it in the balance cock it looked a lot better. I played with the hairspring where it came out of the stud and I thought it was worth trying it installed on the balance in the main plate to see what the overall shape looked like. 

Second attempt 

With the balance back installed, I had to play around with the depth of the stud but this got the overcoil located vertically so it isn't touching either the balance cock or the spring. The main coils of the hairspring still has a bit of a lean to it. I think this is where it comes off the collet so I will probably have a go at trying to get that flat. The overcoil also seems to be slightly high compared to the balance cock. It doesn't touch anywhere since it actually dives down back to the main coils before coming near the balance cock.

When spun up with a fine paint brush the balance oscillates quite well and the hairspring seems to 'breath' without touching anything. I can't tell if the hairspring is having too much of an effect on how free the balance is as I still haven't cleaned the jewels so it's still a little sticky. I will take the hairspring off the balance cock again and run the cock through my normal cleaning cycle along with the rest of the movement. Not going to take a risk with the 100 year old shellac in the ultrasonic. 

 

 

[nevenbekriev]

Sorry, but much more is needed to say it is OK. The spring is not centered, but this is small issue. The spring may be not parallel where gets out of the collet, but this is small issue too. The problem here is the height of the overcoil above the main body and the overcoil to be in one plain parallel to the main body. But some side view pictures of the spring are needed so that we can see the situation.