Tissot 784 Hairspring not centered

[tellemsoulja]

Hi! 

The hairspring to my Tissot 784 is not centered, probably messed it up in the cleaning process. Is the hairspring bent or maybe something with the stud? Thanks! 

[Waggy]

Looks like it is best right at the stud, you could try fixing it, but it's delicate work and even the experienced amongst us don't look forward to working on hair springs.

[nickelsilver]

It's bent right where it passes through the regulator. There is probably a distinct bend there. Bring it back so the regulation curve is uniform again and you will be close, do the final adjustment in the watch.

[tellemsoulja]

Thanks for fast answers! Have I correctly marked the spot Nickelsilver mentioned? Bending it "inwards"? 

[Willow]

If you go on you tube and and type in Chronoglide watchmakers next to where it says store you can search what video you want, type in repair balance spring, and you will see 3 videos how to do it, i think its the 3rd one which you might interest you, but i would watch all 3 

[nickelsilver]

18 minutes ago, tellemsoulja said:

Thanks for fast answers! Have I correctly marked the spot Nickelsilver mentioned? Bending it "inwards"? 

Yes, there. It should be a smooth curve along the path of the regulator.

[transporter]

is it just me, but I cant see the actual hairspring pinned to the stud, also the balance isnt sitting in the jewel so its bound to be out of shape

[nevenbekriev]

It is pinned to the studd, thow not seen well on the picture.

OP, may be for You will be easier to open the regulator and untighten the studd carier screw, then put the balance with the hairspring out. Of course, the spring can be reshaped without this disassembly,  but it will be more clear for You where to work on when it is out.

[Jon]

3 hours ago, tellemsoulja said:

The hairspring to my Tissot 784 is not centered, probably messed it up in the cleaning process. Is the hairspring bent or maybe something with the stud? Thanks! 

How did you clean the balance assembly, by hand? If you clean the balance and mainplate together, so the balance is mounted on the mainplate, this wouldn't happen, unless you're prodding with a brush if it is hand cleaned.

Funnily enough, my students have just spent the last three weeks learning how to manipulate hairsprings and shaping end-curves, first by working on clock hairsprings, then scaling it down to ETA 6497 hairsprings.

It isn't a bad bend, but I would remove the hairspring from the balance and then lay the hairspring on the underside of the cock then bring the end-curve back to where it should be. It's very important to place the stud in the stud support and tighten with the screw to get it to position properly to give you an idea where the collet will end up once assembled. There is a small groove in the stud that the screw will locate with.

I've taken some photos of a clock mainspring and drawn the underside of the balance for it to position on.

The first pic is the underside of the balance cock (I know the curb pin and boot is quite a gap, but I wanted the pic to be understood well).

The second pic is how the hairspring and end-curve should ideally be with the collet bang on the jewel hole. When the index is moved the hairspring shouldn't be pushed or pulled by the curb pin and boot, or in modern watches the regulator pins. If that happens you'll see a difference in beat error when you move the index arm from fast to slow. You have to make sure there is a gap between the curb pin and boot before you move the index, otherwise it will bend the hairspring, which might have happened in this instance.

The last pic is the hairspring being manipulated to form the end-curve again. This is done away from the cock and then try for shape on the cock remembering to ensure you tighten the stud screw to get the proper position of the spring. I have gripped the spring with No. 7 tweezers and where the arrow is, push the spring until the kink is out and the collet is on the jewel.

If you've never done this type of work before, it's best to try with a scrapper first. It is a lot safer to remove the hairspring from the balance first. I use scalpels to lever the hairspring off, or very fine hand removing tools, but I still prefer scalpels 

Edited April 2, 2024 by Jon

[nevenbekriev]

Nice and clean explaination!

[Nucejoe]

Laser welded collets limit your sorting  the hairspring  with the balance attached, a pain. 

If collet is removable detach the balance & hairspring. then; 

 

On 8/13/2019 at 9:41 PM, JohnR725 said:

 

 

Good luck 

[canthus]

When I first started manipulating hairsprings I wrecked plenty simply because I let my tweezers open too quickly.  My fix for this was to put a small elastic band (or similar ring that won't slip) around the tweezer and slide it towards the points to reduce the 'normally open' gap. Then if you let go too soon the tweezers will not open to a large gap and possibly wreck some coils.

I also keep a couple of tweezers just for hairsprings, having dressed them to be true and square.

Don't tackle if you are tired or time pressured.  Take a rest if you are getting annoyed with yourself !!

Sometimes on the bay you can get a cheap mixed pack of balance springs.  Whilst these may be in good shape, you can practice by creating your own damage and then repair it without any risk.  Your current problem could easily be replicated this way so you can the try to repair as practice before working on your movement.

PS I still  manage to wreck some.

Edited April 2, 2024 by canthus

[Nucejoe]

 Locking tweezers is inspiring to alter regular tweezers for the purpose Canthus explained. 

https://www.amazon.com/Diamond-Tweezers-Stainless-Serrated-Straight/dp/B098QTSP82

The design can be simplified to just a screw limiting the arms.

[tellemsoulja]

Thanks everyone, really helpful replies on my first post here. The balance needs a bit more tweaking but atleast it runs now!

[JohnR725]

9 hours ago, transporter said:

is it just me, but I cant see the actual hairspring pinned to the stud, also the balance isnt sitting in the jewel so its bound to be out of shape

yes one of the minor problems of having a balance wheel out of the watch is it's not necessarily in the same position as it would be in the watch. In other words in this case it's leaning slightly which is going to cause a minor problem. Which is why the final tweaks will have to be done in the watch or verified in the watch to make sure your successful as opposed to out of the watch it looks perfect.

[Jon]

20 hours ago, Nucejoe said:

Laser welded collets limit your sorting  the hairspring  with the balance attached, a pain. 

I find laser welded collets will come off the staff given enough patience and flexing of the scalpels. 

The trick is once the hairspring work has been completed to slightly close the collet hole up by about 0.15 mm with domed stakes top and bottom in an 'inverto' staking set before refitting, as there is no longer a weld and it was never friction fitted, so the friction has to be created. I use a smoothing broach to gauge how much I've closed up the hole with the staking set.

I posted on my Instagram (https://www.instagram.com/jonthewatch/) the second year students performing all these processes and they all nailed it. They started practicing with clock hairsprings which I showed in my earlier post, then scaled down in size to an ST36 spring (clone of ETA 6497) which is still a fairly large spring! Once you know what you're doing, I find it really relaxing work, as you a totally in the present moment. No thoughts of past or future, just there and then. Almost meditative.