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NOS hairspring 180 degrees out of position


gaber

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Greetings all.  I've been working on a few things but one is a bit curious so I thought I'd report.  I snagged this non-running, but otherwise lovely little Elbon watch off ebay:

IMG_20200911_190817.thumb.jpg.c8350b2771674f5ca13b125195e292ba.jpg

I really like the style of the dial; was very excited when it arrived.  When I inspected inside, I noticed that the balance wasn't oscillating freely, and was very loose -- had a lot of end shake.  I quickly diagnosed the problem as a broken pivot on the balance staff.  Here's a comparison of the two pivots:

1356067142_ScreenShot2020-09-24at7_07_18PM.png.3d06cecffac5312814e1fb0bef0871e2.png

One is not looking great!  So I found a NOS balance complete online (for the exact movement) and ordered it.  This one should be straightforward, open and shut, I thought.

Well the part finally arrived from the Netherlands, after the usual Covid shipping delay, and I noticed some strange things.  First, it had a lot of little spots of blue-green corrosion, especially on the hairspring collet (brass -- perhaps the source), but I managed to clean that off.  Also the hairspring itself was sticking to itself in one place, and I had to spend a bit of time cleaning it with a brush and benzene.  Soaking it wasn't helping.  Then I put it side by side with the old balance and noticed that the position of the end of the spring (the stud) was 180 degrees different between the two.  See this picture (note the impulse jewel are both pointing south, though you can't see them):

IMG_20200924_184741_2.thumb.jpg.1b9443ab4af5477ebf2c94acd87b45a8.jpg

I did not even try to install the new balance.  This cannot be right.  I think I may try to just swap the hairsprings, though this will be a first for me.  I could try using razors as recommended by @Nucejoe.  The old hairspring looks a bit better shaped too, as it angles out to make contact with the regulator arm. 

What do you guys think about all this?  Shouldn't a new part have a correctly positioned hairspring, etc?

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Despite sameness of caliber, hairsprings might not interchange. 

Each hairspring was vibrated with the wheel it is on.

I just turn the new hairspring by 180 degrees.  If you happen to take the hairspring off of the wheel you have a chance to brush the hell out of the balance, usually chemicals like  one dip is used to clean hairsprings, you should in no way attempt cleaning H/S physicaly.

You might soak the hairspring in lighter fluid overnight for a good clean.

Save the old balance complete to re-staff.

Good luck

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There is a chance is from the same family with different build, some manufacturers use the same wheel over a few models. Do as  Nucejoe suggests and move the balance spring into position to match the old one. Also check the balance rim for a stud index mark it may have been placed on wrong in the first place.

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That balance has a different number of screws, a different number of hairspring coils and a significantly different stud location. 
 

It could have the hairspring accidentally fitted 180 degrees around, or it could be from a different caliber. It’s unlikely to be the former if it is NOS as it would be roughly adjusted for beat-error in the factory. 

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The two balances look diferent, hairspring is positioned diferent, Good chance rodabod is right.

Drop the new balance complete in, tighten the cock as you normally would to see impulse jewel and fork engage and do a perfect impulse.

 

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I think it could be the right balance, the terminal curve on the new one isn't formed, just a slight bend at the stud. It's not unfathomable that the supplier offered replacement balances like this especially if they fit different calibers; it's about 5 minutes work for a watchmaker to finish the outer coil.

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I once had a Renata or similar replacement balance for a horrible Cupillard movement which was supplied with the terminal curve unformed. But it would still surprise me if the hairspring was installed 180 degrees out.

I would not expect things to work if you swap the hairspring over as they are different hairsprings and different balance wheels, so I wouldn’t expect them to vibrate at the correct rate if you swapped them. 
 

Check that the rollers, or at least the dimensions of the interfacing parts look identical. 

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Staff and roller might differ, so I put the new balance with the roller attached plus the fork and put the cock on, if it fit and did impulse, I might have chance to build a balance complete. 

47 minutes ago, clockboy said:

If it was me I would just move the impulse jewel and the end of the hairspring to the same positions as the old.

Isn't moving either one enough?

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5 hours ago, Nucejoe said:

Staff and roller might differ, so I put the new balance with the roller attached plus the fork and put the cock on, if it fit and did impulse, I might have chance to build a balance complete. 

Isn't moving either one enough?

I mean , moving roller ruins balance poise whereas hairspring wouln't as much or would it.

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Thanks for the feedback, everyone.   That was all very helpful.  I tried to synthesize it all:

It seems there is reason to worry about compatibility between the different springs and wheels, and I should pause before swapping them (Nucejoe, rodabod).  There is even some worry that the part is just wrong.

I have visually inspected the roller and the jewel layout, and they look the same, but this is not a precise comparison.  The position of the stud seems especially odd, assuming the part is correct for the caliber.  Indeed, does the stud ever attach to the balance cock on the opposite side of the wheel, in any movement?  The hairspring just seems incorrectly positioned to me.  (I did not however find markings on the rim to support this theory, rodabod).  Then there's this:

10 hours ago, nickelsilver said:

I think it could be the right balance, the terminal curve on the new one isn't formed, just a slight bend at the stud

This makes sense to me.  This gives me an idea: Perhaps the manufacturer of the balance has installed the spring 180 degrees out on purpose, to tell the watchmaker that the spring needs to first be taken off and finished before used?

4 hours ago, Nucejoe said:

I mean , moving roller ruins balance poise whereas hairspring wouln't as much or would it.

This discussion is interesting.  I hope 180 degree turn on the hairspring will preserve the overall poise of the wheel.  I imagine that the brass collet contributes some mass to the wheel, but this mass is very close to the axis of rotation, and the collet is very nearly symmetric, so one could argue that adjusting it should not change the (moments of) inertia much, and therefore the poise would be preserved.

*****

Given all this feedback, I believe the course of action that would produce the best chance of success (assuming I don't mess it up) would be to just use only the new balance and do the following:

(1) Remove the hairspring from the wheel.

(2) Finish the hairspring by reshaping the terminal coil, so it lines up correctly on the balance cock.  I found an old instructional video on this process.

(3) Remount hairspring on the balance in the correct position.

Sounds good?

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1 hour ago, gaber said:

(1) Remove the hairspring from the wheel.

(2) Finish the hairspring by reshaping the terminal coil, so it lines up correctly on the balance cock.  I found an old instructional video on this process.

(3) Remount hairspring on the balance in the correct position.

Sounds good?

That sounds like a good plan. It's usually easiest to make the necessary adjustments to the spring with it mounted by itself on the upturned cock.

 

The balance is poised with the roller in place, that is normally as far as poising goes. Very high grade watches might have modified hairspring collets that compensate the small error a normal one may introduce, but even a standard collet is pretty close (they drill for the pin opposite the slot). In more modern times much better collets have been developed that are extremely well poised. All that to say you won't mess up the poise by turning the spring 180 degrees. Turning the roller will affect it though, in some cases it's quite a lot.

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The plan is good providing you have checked that balance fits in place and impulse jewel interacts with fork as it should. 

The new balance complete is NOS (according to the seller) so I regards it as poised and at least wouldn't touch its roller, do your number with the hairspring.

Good luck.

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Thanks guys.  One more interesting clue:  I checked again the ebay advertisement and the "N.O.S." part shown in the picture has the hairspring stud in the "correct" position (right side)!  Here is the pic from the advertisement:

s-l1600.thumb.jpg.4e562bdb3bad861180aad5bb1471f368.jpg

Note to compare with my picture one needs to flip it top to bottom (about the spoke), so then the jewel is underneath and point south.  This supports the theory that the hairspring was installed 180 degrees out at the factory.  The guy has 73 of these parts available...  I got unlucky I guess..

Edited by gaber
clarity
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While you have the hairspring removed, I would drop the balance into the movement to see if it fits with reasonable end-shake. Don’t worry about getting the impulse jewel into the lever as it wouldn’t act normally without the spring fitted anyway. 
 

Do look at the old spring for reference, even though it’s not exactly the same. Compared to a plain spiral, there are at least two manipulations made: one to decrease the radius of the terminal curve, and one to dog-leg the stud to be closer to the balance rim. The exit angle of the spring from the stud may also be different, and this is most easily adjusted with the spring fitted to the balance cock in my opinion. I’ve no idea how much experience you have of doing this, but try to keep your tools (tweezers or pins for example) upright/perpendicular so that you do not alter the flatness. 

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Hi all.

One step forward:

 

IMG_20200926_083016.thumb.jpg.4fbe711d24a8997cd66c83c698e952a1.jpg

00100dPORTRAIT_00100_BURST20200926083631490_COVER_2.thumb.jpg.26560d075b46cc2022a7b073a4c5c6ca.jpg

 

Two steps back:

00000IMG_00000_BURST20200926090936059_COVER.thumb.jpg.15607a488d36ff9d1e0ce61c626caf0c.jpg

There's supposed to be a little pin on the regulator arm that helps to enclose the terminal curve.  Looks like it was snapped off at some point.  Just a little stub remaining.  I think I will need a new balance cock for this one....  Doesn't seem that the arm is sold by itself.

 

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H Joe, The movement is AS 1002.  Here's a photo from when I was stripping it down for cleaning:

IMG_20200912_105850.thumb.jpg.55c264f973b5172d5c92107520aa137d.jpg

I have found balance cocks, some complete and some incomplete, advertised for 984 - 1002, but of course they do not match mine exactly.  The regulator arm on them perhaps will match....? 

Mine is unusual looking: the part that holds the jewel down ("jewel cock"?) has a long thin arm with two screws:

00000IMG_00000_BURST20200926101439263_COVER.thumb.jpg.ba08c66ec93c285377f02a2d9af286fc.jpg

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2 hours ago, Nucejoe said:

 Variants of AS1002 often have different bridge layout, but regul arm interchanges beteewn them, I am sure a used one can be found. 

This odd shape of the end stone plate wouldn't change regul arms adaptability.

 

OK, thanks, then I'll put in an order for a balance cock.

To answer an earlier question from rodabod, the fit of the new balance wheel is a bit snug I'm afraid, although it does seem to interact correctly with the fork.  I would say there is zero endshake, and it does not rotate freely, but moves easily with a light push from the tweezers.  Have a look at this:

I seem to remember that the balance cock can be raised a bit by putting some kind of dent/scratch in the mainplate.  But this isn't best practices.

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No need to gauge the mainplate, just shim the bridge up, place a thin piece of foil under the cock to create some endshake, sometimes you can just move jewels to get some endshake. 

You replace the regulator arm with a good one at the most. The micro-pin can be punched out on a staking set and replaced.

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32 minutes ago, Nucejoe said:

No need to gauge the mainplate, just shim the bridge up, place a thin piece of foil under the cock to create some endshake, sometimes you can just move jewels to get some endshake.

Think these marks were put to tighten the balance cock? 

IMG_20200926_135402.thumb.jpg.7e5200864fd71e95dd7d706f2f40341e.jpg

Maybe if I remove them somehow, this will give the endshake?

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That’s an early anti-shock setting. When you bought the balance complete, was it described as being for anti-shock in any way? Eg. “Inca”?

The new wheel either does not have enough end-shake, or something is fouling such as the roller or the rim (you need to look closely to check for this). This assumes you screwed down the balance cock neatly. 

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