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Tweaking a Breguet hairspring with "normal" tweezers.


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Hello All;

I'm working on a vintage chronograph pocket-watch which has "some" challenges. One of those is the Breguet hairspring.

The trouble starts at the last outer coil. It seems to have an "okay" up-bend but the second "down"-bend doesn't seem to exist and so the terminal end of spring makes its way to the stud as a kind of rollercoaster track.

From the books I have, so far "Bench practices for Watch repairers" by Henry B. Fried, has given me the best guide, but those are not enough "hold-on" for me.

I don't have the fancy Breguet tweezers (2 types mentioned in various books), so I have to do it with 2x Dumont N˚7 hairspring tweezers or any number of my Dumont straight tweezers.

Has anybody some clear instruction to create the up- & down-bends with normal tweezers?

On the forum I've found a tip of member @ic0n which seems to be a good idea. (https://www.watchrepairtalk.com/topic/27838-nifty-idea-for-helping-adjust-hairsprings/#comment-233789

Here are some pictures, taken in quarter turns of the balance-wheel, of the spring on hand, so you get an idea ...

S20231202_005.jpg.55dc4e8464f5c7898d43d73568946275.jpg

S20231202_004.jpg.ff8675acb3ebf84e08cfdf813f08a376.jpg

S20231202_003.jpg.2c5d16a2c1e8a639892e7f211ec0498d.jpg

S20231202_002.jpg.c5e72b492a870298734f25be6cf1f58e.jpg

S20231202_001.jpg.ae4f116e5522c8ec8bb438fff369c70c.jpg

Once I've have sorted out the up- & down bends, and have the terminal end horizontal, next will be the correct curvature for the regulator & the stud.

 

Edited by Endeavor
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43 minutes ago, Endeavor said:

From the books I have, so far "Bench practices for Watch repairers" by Henry B. Fried, has given me the best guide, but those are not enough "hold-on" for me.

On page 68 he shows how  to make a vertical bend by pushing in to a block of soft wood. I've used this method with some 'normal' tweezers to correct a vertical bend. 

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I have empathy for overcoil issues- not for the inexperienced or the faint of heart. Questions I have often go unanswered but I’ll be interested in the pros weighing in…

…that said I think fortunately for you you are adjusting rather than creating and I don’t think yours looks so bad.  A couple think out loud thoughts- first is the weight of the stud causing much of the ‘roller coaster’? Examine what it looks like off the balance wheel but in the stud. You may only have to apply Fried ‘in the flat’ techniques to correct…

…and I’ve used the rodico trick to help with terminal but not for an overcoil. Again yours doesn’t look so bad so maybe- again mounted stud with balance missing- a little adjustment to center the collet could be all the improvement you need?

Edited by rehajm
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44 minutes ago, Endeavor said:

Once I've have sorted out the up- & down bends ...

So good luck!

There are overcoils that climb without those 2 bends, but really rare and made by masters. Yours is not at all a master's work.

Easiest way to correct bends in the height is a very rigid tweezers with sharpened tips, pushed with the hairspring blade into wood (just mentioned above) - no #7 at all! Even better than pushing is driving with slight hammmer blows. Try first with scrap hairsprings!

Frank

 

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4 minutes ago, rehajm said:

I have empathy for overcoil issues- not for the inexperienced or the faint of heart.

I hate working on overcoils - you have to be careful with resting the tweezer tips when making adjustments as you can mess up coils below.

 

3 minutes ago, praezis said:

is driving with slight hammmer blows. 

I'll be having nightmares tonight 😯

Edited by mikepilk
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I very rarely use my overcoil tweezers in spite of having a full set. I might use the ones that simply curve the raised coil sometimes, but even there not really. If needing to adjust the actual height where it raises up I do as Mike and Frank mentioned, stout tweezers and wood. But it's rare for that to be truly faulty- I can see on your spring I would probably use two pairs of tweezers* to lift/lower the opposing part of the coil in several places to bring things flat again. To get the last part of the curve right leading to the stud, I set the spring on the upturned cock (spring right-side-up), collet centered over the jewel, and count the coils to the regulator. Then make it so the terminal curve follows that coil of spring. It gets it 90+% there, final tweeks in the watch.

 

*The most dangerous thing you can do is use two pairs of tweezers on a hairspring, but sometimes it's necessary. Careful careful careful.

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My coil may not be "that" bad, but enough to push the coil out of the cylindrical shape and out of the horizontal plane when the stud is mounted. If & when the coil doesn't touch the balance spoke, the max amplitude is between 90 and 180. This depends on how "successful" I've been so far with manipulating the hair-spring. I've managed to get a decent escapement wheel recoil and with everything else pretty correct (lock,draw, total lock, horn-shake, guard-pin shake etc) the amplitude should be higher.

Last thing I want is to screw the hairspring up even further due to lack of know-how.

The bottom balance staff pivot has a grove in it, but that's another problem to sort out in the sequence of problem solving.

I like to sort out the hairspring first.

43 minutes ago, mikepilk said:

On page 68 he shows how  to make a vertical bend by pushing in to a block of soft wood. I've used this method with some 'normal' tweezers to correct a vertical bend. 

Thanks, yes I've seen that 😉 But, as said, those instructions are currently a bit above my head and I was hoping for that somebody had the "how-to-make-a-Breguet-hairspring-in-two-easy-lessons" 😁

 

8 minutes ago, nickelsilver said:

*The most dangerous thing you can do is use two pairs of tweezers on a hairspring, but sometimes it's necessary. Careful careful careful.

Thanks & Exactly. Hence my search for guidance 😉

Edited by Endeavor
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22 hours ago, mikepilk said:

On page 68 he shows how  to make a vertical bend by pushing in to a block of soft wood. I've used this method with some 'normal' tweezers to correct a vertical bend. 

After studying the hairspring and how the existing up-bend was made (clearly with some sort of "offical" / dedicated bending tool), I do now understand the theory on page 68 onward. Next is testing which wood is soft & hard enough? Have to try on some scrap hairsprings what works by which type of wood; pushing by hand or perhaps gentle tapping with a hammer?

Here is one more picture of the one-and-only (up) bend. Why the down-bend wasn't done is a mystery?

The brown spot doesn't seem to be a crack, but I do presume some surface stress-corrosion.

S20231203_001.jpg.d0324c8504bc1c6ceccac630dcfb2f9b.jpg

21 hours ago, rehajm said:

A couple think out loud thoughts- first is the weight of the stud causing much of the ‘roller coaster’?

All the pictures are taken with the balance wheel in the vertical or near vertical position, minimizing the axial influence of the stud-weight 😉

 

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25 minutes ago, Endeavor said:

 Next is testing which wood is soft & hard enough? Have to try on some scrap hairsprings what works by which type of wood; pushing by hand or perhaps gentle tapping with a hammer?

I have a small block of pine wood. Hard enough to work on, but allows the tweezer tips to push in. 

I think it was Frank who suggested the technique to me. 

I had to play around shaping the tweezer tips until I could get a good enough grip on the hairspring, as it's right at the tips.  Once you've tried it, it's not a difficult technique, and quite controllable - I found just a gentle push was enough. 

I've used it on outer coils which were bent near the stud. I don't see how you could use it on the actual overcoil though?

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Yesterday I did several bending attempts (with "normal" tweezers) on a small (ladies-watch) hairspring and the results were poor at best.

I noticed that while pushing the tweezers in the wood that either the hairspring slipped upwards in the tweezers, or that the tweezers would suddenly "sink" in the wood and bent the spring beyond repair. The soft-wood I tried was everything but consistence in its resistance. At a certain spot on the wood one had to push hard to penetrate the tweezers, on a spot next to the previous, the tweezers would sink in deeply when applying the same force.

I decided to make an attempt to mimic the tweezers depicted on page 68 ("Bench practices for Watch repairers" by Henry B. Fried)

IMG_3146.thumb.jpeg.2a39ddbaf66182cc51974a577198a654.jpeg

 

For that I took some some pointy brass tweezers. The "pin" chosen was the thinnest needle I could find: 0.6mm

Hand drilled a 0.5mm hole through both legs, close to the dressed tweezers tips:

IMG_3144.thumb.jpeg.37215e68e2033ff9e36c7fda6b676e54.jpeg

With the needle inserted;

S20231204_001.jpg.ff7b55d6666a6e1e54aac6162b096c64.jpg

S20231204_002.jpg.b0154d173ac0cb52b0315252839e5413.jpg

I could have trimmed the needle off, but as it turns out, either end of the needle do act like a safety, preventing the tweezers from "sinking" too deep into the wood. I also started to use another, more homogeneous "hard-wood", offering a more consistent resistance.

I did a few more test on another PW-hairspring and the results were very good, very controlled and producing consistent bends. The bend produced is, due to the relative large radius of the needle, not as "sharp" as the first bend, but it does the job very nicely. Because the needle extensions are starting to "rest" on the wood, the bending goes very controlled.

I'm not done yet with my hairspring, but the second (down) bend sits in without damaging the "one-off" hairspring. Adrenaline back to normal levels 🥶 

On the picture it looks like that the 2nd bend is a bit "over-bend", but that's only when you take the twisted continuation of the spring as a reference.

In reality it's spot on, back to horizontal 😉

S20231204_003.jpg.84f89a5c883c7b5e772dcdfaa567bc20.jpg

Next is to sort out the terminal curvature ........

Edited by Endeavor
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1 hour ago, Endeavor said:

Yesterday I did several bending attempts (with "normal" tweezers) on a small (ladies-watch) hairspring and the results were poor at best.

I noticed that while pushing the tweezers in the wood that either the hairspring slipped upwards in the tweezers, or that the tweezers would suddenly "sink" in the wood and bent the spring beyond repair. The soft-wood I tried was everything but consistence in its resistance. At a certain spot on the wood one had to push hard to penetrate the tweezers, on a spot next to the previous, the tweezers would sink in deeply when applying the same force.

I decided to make an attempt to mimic the tweezers depicted on page 68 ("Bench practices for Watch repairers" by Henry B. Fried)

IMG_3146.thumb.jpeg.2a39ddbaf66182cc51974a577198a654.jpeg

 

For that I took some some pointy brass tweezers. The "pin" chosen was the thinnest needle I could find: 0.6mm

Hand drilled a 0.5mm hole through both legs, close to the dressed tweezers tips:

IMG_3144.thumb.jpeg.37215e68e2033ff9e36c7fda6b676e54.jpeg

With the needle inserted;

S20231204_001.jpg.ff7b55d6666a6e1e54aac6162b096c64.jpg

S20231204_002.jpg.b0154d173ac0cb52b0315252839e5413.jpg

I could have trimmed the needle off, but as it turns out, either end of the needle do act like a safety, preventing the tweezers from "sinking" too deep into the wood. I also started to use another, more homogeneous "hard-wood", offering a more consistent resistance.

I did a few more test on another PW-hairspring and the results were very good, very controlled and producing consistent bends. The bend produced is, due to the relative large radius of the needle, not as "sharp" as the first bend, but it does the job very nicely. Because the needle extensions are starting to "rest" on the wood, the bending goes very controlled.

I'm not done yet with my hairspring, but the second (down) bend sits in without damaging the "one-off" hairspring. Adrenaline back to normal levels 🥶 

On the picture it looks like that the 2nd bend is a bit "over-bend", but that's only when you take the twisted continuation of the spring as a reference.

In reality it's spot on, back to horizontal 😉

S20231204_003.jpg.84f89a5c883c7b5e772dcdfaa567bc20.jpg

Next is to sort out the terminal curvature ........

Nicely done Endeavor, choosing the correct spot in your timber will make a difference. I found pine or white wood with a medium- tight grain to be a good choice, placing the hairspring across the grain and sharp tweezers pushing into the summer growth, but very controlled,  both hands made controlling easier. Not on overcoiled forming but straightening vertical bends.

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Some hints:

- position the hairspring blade perpendically to the grain.

- pushing too deep can be avoided by the laughed upon hammer taps.

- the hairspring will slip up if the tweezers is too weak.

Else: congratuations on your progress!

Frank

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Getting there, the terminal end sits pretty horizontal and the regulator ark runs over the 10th coil from the center jewel. Like @nickelsilver said, final tweaks once mounted on the balance wheel and in the watch.

BTW; with two tweezers (I used 2x Dumont N˚7) under the stereo microscope, due to limited depth-of-field, one wrong move and the hairspring turns into a ball of spaghetti ......

To be fair, somebody warned me 🙂

On 12/2/2023 at 5:42 PM, nickelsilver said:

*The most dangerous thing you can do is use two pairs of tweezers on a hairspring, but sometimes it's necessary. Careful careful careful.

S20231205_001.jpg.63fa289e41481ba13ac3dd796313ae1c.jpg

Thanks all for your help 👍 😉

 

Edited by Endeavor
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1 hour ago, rehajm said:

...that looks great- well done. Does there need to be some last coil cleanup or is that just the way the unmounted spring is resting?

Thanks 😉

By "eye" the collet may be a bit off the horizontal, but I've to see when mounted. It all may need to have a little tweak left / right / up or down, but in general the hairspring looks to be in a much better shape than before.

As for the amplitude; the balance pivots are in a bit of a mess too, so we have to see ........ one step at the time 😉

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2 hours ago, Klassiker said:

Are the tweezers and the pin brass, or steel? Did you fit the pin yourself? Do you use the toothbrush handle instead of wood?

The tweezers are useless steinless antimagnetic swiss made nonsense, the pin is guitar string (pivot wire), I have drilled the holes and inserted the pin and formed the tips. Yes, I use the rubber on the handle instead of wood.

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14 hours ago, nevenbekriev said:

Yes, I use the rubber on the handle instead of wood.

I would assume, just like the hardwood I'm currently using, that the rubber gives a constant and a homogeneous / repeatable resistance. BTW, it such a good idea, my wife can't find her new toothbrush anymore 💩 🤣

Had to do the over-coil bends over again 😞  The height of the over-coil turned out to be too high. With the terminal-end being so mangled up, I adjusted the height as suggested in Henry's book; two or three times the width of the hairspring, but that was in my case too high and the spring touched the bridge. I ended up with a height of 1.5x the width of the hairspring, at most.

The movement is running again but sadly with not much improvement in the amplitude; around the 170 degrees Dial Down...... Dial up and the amplitude crashes. I'll dig deeper, but that goes off-topic 😉

 

 

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