Bent Hairspring

[David Dikun]

I have this hairspring off a OMEAGA movement 25.6 and I don't have enough experience to understand how the hairspring should bend. If I had a good one I could use that to reference it.
Is there anything I can use to reference the bends? how should I go about this? I have H.B. FRIED book "Bench Practices for Watch and Clockmakers" which helps, but still bit loss.

 

[Skutt50]

I would suggest that you start with a good cleaning to remove the possibility of clinging coils due to oil or dirt. A demagnetization is also recommended.

- The shape should be such that the hairspring rests evenly between the adjustment pins during the full movement of the adjustment arm.
- The coils should be centered and even during the entire movement of the adjustment arm.

 

[gmorse]

Hi David,

After taking Skutt's good advice about cleaning and demagnetising, you should look very carefully at the two areas marked here:



The point where the spring exits the stud, (in green), should have no bend at all, and the point at which the overcoil begins to rise and turn inwards, (in red), should have a smoother curve. Before any thought of correcting these two areas, the hairspring collet must be removed from the balance staff; this process should be well covered by Henry Fried. Both these relatively sharp bends will need to be corrected very gently and gradually to avoid snapping the spring. Try to stroke them in the right direction with fine tweezers and/or a blunt needle in a piece of dowel as a handle. It's a delicate operation which is best done in a quiet place and in a calm mood!

Regards,

Graham

 

[praezis]

You have a variety of issues here:

- kink at the stud
- stud probably fixed wrong way
- coils in the main level don't have equal distances
- form of Breguet coil
- missing bend at the transition Breguet coil - concentric terminal coil

This is surely no task for a beginner, even most watchmakers will have a problem here.

Frank

 

[David Dikun]

thanks all!
Graham, you mentioned a smoother curve,how should model this curve? can you overlay a image?

 

[gmorse]

Hi David,

My best advice, taking into account the very valid and sensible points made by Frank Praezis, (if you really intend to attempt this yourself), is to read the Chicago School of Watchmaking Course, which covers this topic amongst many others and is available free online if you do a search, and then practice on some scrap watches before you try and fix this one. Manipulating hairsprings is something you can only learn by practice, and in the process you will, inevitably, destroy several springs.

Regards,

Graham

 

[Ticktinker]

It looks as though the last couple of coils before the breguet seem to be bunching together.
A hairspring's coils should be uniform.

 

[karlmansson]

Couldn't agree with with Graham more! Try this out on practice balances first. It takes a couple of working weeks and several tension headaches before you get adept at this and work out your own methods and work out the kinks in those methods.

Best of luck!

Karl

 

[RJSoftware]

One thing you might want to consider also is that this could be a beryllium hairspring which are very expensive. I say that because the Omega I have has one and I found out the hard way after it broke at the collet. I think it's a choice rare ,metal good for hairsprings because it responds well in temperature. Not sure I recall exactly. But I do remember it's expensive.

 

[karlmansson]

I've never come across pure beryllium hairsprings and I can't really see what benefit they would have. Beryllium can however (apparently) be found as an alloy in certain variations of Nivarox springs and I think also Invar. Most modern watch balances have hairsprings of these non-magnetic, temperature stable alloys.

I find it unlikely that this would be anything other than a blued steel spring, judging from the split arm, temperature compensating balance. Plus the colour. That's not to say that finding a replacement spring won't be very expensive! In this case I think it comes down to rarity of cost of labour rather than the cost of materials.
Pure beryllium can be bought online for about 20 dollars to the gram. I'll take this opportunity to point out that it's highly toxic upon ingestion and never to machine it dry and without a breathing mask. This comes into practice when drilling to poise glucudyr balances as well. Be sure you see where the chips end up! (Glucudyr is a beryllium containing alloy).

Best
Karl

 

[pmwas]

It looks as though the last couple of coils before the breguet seem to be bunching together.
A hairspring's coils should be uniform.

It looks like it's terribly damaged...
It's fairly easy to work on hairsprings with bent terminal coil. If there is something bent in the middle-, it's a disaster - making the coils uniform and keeping their distances and curvatures is a nightmare. Slight adjustment might rthen cause major effects, the effect can be completely different from what you'd expect and... it's hard to see where exactly the coil is bent.
I think this one will be very difficult to get right, and I'm quite sure it will break in the spots gmorse has marked, when you try to straighten it.
The green marked spot might break off, it's no big deal to move the stud this much, but the red marked spot - disaster...

If it's a blued steel hairspring, I'd probably look for a replacement.