American PW Advice on how to reduce the height of hairspring overcoil

Discussion in 'Watch Repair' started by MikePilk, May 3, 2016.

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  1. MikePilk

    MikePilk Registered User

    Nov 23, 2014
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    I have a 16s Elgin Veritas where the hairspring is touching the balance arms as the overcoil is too high, causing the spring to cone downwards.

    What is the best way to reduce the overcoil height - a twist inwards at 'A', then a twist outwards at 'B' ?

    veritas_hairspring.jpg
     
  2. pocketsrforwatches

    pocketsrforwatches Registered User
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    #2 pocketsrforwatches, May 3, 2016
    Last edited: May 3, 2016
    Before you do anything, think about this for a minute. What would cause a hairspring to change its shape? In all probability you have another condition that is causing your problem unless someone has messed with it before. Also, something seems odd with the timing screws.
     
  3. Mark UK

    Mark UK Registered User

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    Mike, points A and B are a good place to start. How much twist you put at A will depend on how close it is already to the next inner coil. Putting the outward twist at B will also have the effect of making the slope to the stud steeper (which is what you are aiming for) but when you put the stud back in the balance cock it will have the effect of tilting the whole spring at an angle.... to get it to lay flat you can loosen/remove the taper pin at the stud to relieve the tension and try to settle the spring down, you may need to make a few more subtle inward/outward twists to get the spring to lay flat :)
     
  4. MikePilk

    MikePilk Registered User

    Nov 23, 2014
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    The numbers on the balance don't match the watch. The timing screws at the end of the arms are very strange - they have a steel threaded rod through them! So what the balance and hairspring are, I don't know.

    Trying to find a replacement balance/hairspring for a 16s Elgin Veritas Grade 453 is near impossible, so I have to work with what I've got.
     
  5. gmorse

    gmorse Registered User
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    Hi Mike,

    Quarter screws are often like this, effectively tiny bolts with the nuts on the outside.

    Regards,

    Graham
     
  6. DeweyC

    DeweyC Registered User
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    Graham,

    Did you look at those timing screws closely? .

    Before touching the overcoil, it could be the collet height, or even collet not fully seated on the staff.

    If the collet is fully seated and the staff is correct (is the balance a mile above the pallet bridge?) then I would presume it to be a marriage.
     
  7. Rob P.

    Rob P. Registered User

    Dec 19, 2011
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    I think I'd look at the setup VERY carefully. If the stud end of the overcoil is too high, then twisting at A will probably cause interference with the next coil.

    What I think I'd do is look to see if a single inward twist about 1/3 of the way from A to B would lower the height of the stud and prevent the pushing down of the coils into the arms. You'd have to check to see if this will allow the overcoil to pass through the pins correctly. If it won't, then you will need to put in an outward twist somewhere around B to get the overcoil vertical in the adjustment section of the coil. I'm guessing it probably won't need it but I don't have the balance in front of me.

    I'd also check to see if the balance arms are flat and not lifting the rim upward. I mean REALLY flat with no lift at all.

    From there I'd check to see if the staff is correct. It might fit, but put the balance too high under the cock therefore reducing the available space for the HS.
     
  8. MikePilk

    MikePilk Registered User

    Nov 23, 2014
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    I fitted a new staff, and trued the balance - the arms are flat. The collet is seated correctly, and I raised the stud as high as I could in the cock.
     
  9. gmorse

    gmorse Registered User
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    Hi Dewey,

    I see what you mean; I was wrong about the bolts, although that's effectively how these studs are working, and right about the nuts, which are slotted from each end to grip the thread as they should be. One and a half out of two . . .

    Regards,

    Graham
     
  10. gmorse

    gmorse Registered User
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    Hi Mike,

    Another thing to look at is the hairspring collet. Is the hole in the centre vertically or towards the bottom? For an overcoil collet it should be the latter.

    Regards,

    Graham
     
  11. praezis

    praezis Registered User

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    Btw. the overcoil is too short for a correct one.
    The overcoil length from start to regulator pins will take about 1/2 of the outer main coil length. Here we see less than 1/2 up to the stud.
    Does not look original.

    Frank
     
  12. DeweyC

    DeweyC Registered User
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    Mike,

    If it is for someone else, I would explain the situation before going any further. You can maybe point them to this thread if you need to.

    What is your goal with this piece? At this point it looks to me the most likely outcome with the parts at hand is "to make it tick". At which point learning how to form overcoils is a good use for it. Getting it to within 15 seconds/day across 5 or 6 positions seems extremely unlikely.

    If the goal is to return the watch to original performance, you need to find a donor with a matched balance assembly. No rust on balance spring. You can always use the jewels from the donor and may get other parts as well.

    If you find a donor, heed the advice of pocketwatches. You should presume it left the factory perfectly poised so unless there is evidence that someone tampered with it (washers; screw mass removal), think why the poise changed after it was restaffed. It should not change if the rollers are in the original position (only two possible spots on American RR watches) or the balance wheel is not true in the round (assuming the new staff is good).
     
  13. MikePilk

    MikePilk Registered User

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    It's just one of my small collection of pocket watches (only 12 so far). I like to get them restored to near original spec, and running reasonably well, not because I'm going to use them, but I think they should be restored to running condition. I've managed to get the others to within about 15 s/day, a couple much better.

    I've had several goes at this one, and have been looking for a donor balance/hairspring for months - seem impossible to find for this grade.
     
  14. DeweyC

    DeweyC Registered User
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    Good. when you say 15 seconds per, what does that mean? Is that the range of the average daily deviation across 6 positions? Or is that how they perform when worn?
     
  15. MikePilk

    MikePilk Registered User

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    I like to use them occasionally to give them some 'exercise'. I bought a chain so I carry them in my pocket, but a lot of the day they just sit on my desk at work, so not really testing all the 6 positions! My best is a Waltham Riverside 17J, the last time I used it was within a second after 3 days - better than my 19J Riverside.
     
  16. Harvey Mintz

    Harvey Mintz Registered User
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    Your hairspring has definitely been "diddled" - the shape of the overcoil is wrong for an Elgin. Here are a couple of pix of a NOS Elgin balance with overcoiled hairspring for comparison:
    DSCN2548.jpg DSCN2549.jpg

    As you can plainly see, the location that you've marked as "A" in your picture has a fairly tight bend that brings the overcoil much closer to the staff than yours, and then another turn at "B" that ends the straight section of the overcoil and leads to the semi-circular regulation portion of the hairspring. If you want the overcoil to operate properly (and the watch to run without a coned hairspring), the first thing you should do is correct the shape of the overcoil, which will include leveling it so it isn't too high. After that's done, the watch will probably run OK.

    Each company chose their own hairpring overcoil shape, and there's a lot of complex math involved in calculating the shapes. I've seen a write-up (possibly a book) that includes information on many of these shapes, but I can't put my hands on it at this moment.

    Harvey J. Mintz
    "Hey, Buddy - wannabuyawatch?"
     
  17. MikePilk

    MikePilk Registered User

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    Thanks Harvey, it has indeed been "diddled". I have a B.W Raymond and the spring looks like the one pictured.

    I'll see if I can find a replacement, from the info I have it's part #796, strength 2.
     
  18. Skutt50

    Skutt50 Registered User

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    De Carles "Practical Watch Adjusting" contains a lot of tables with how to shape a hairspring.
     
  19. Smudgy

    Smudgy Registered User

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    Watch Adjustment by Jendritzki is probably the book you are thinking of. It has a few pages of pictures of terminal curves and a good discussion. The hairspring is not shaped right and is likely altered from the original shape as suggested by Harvey Mintz. The way it has been altered suggests it was to correct a spring that broke near the stud and the repairman was trying to salvage the spring.
     
  20. DeweyC

    DeweyC Registered User
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    And as you guys know, once the pinning point is lost, there is no hope in returning to original performance. But as the OP state, his main concern is regulating his watches to 15 seconds per day; he is not concerned with positional adjustment.

    That being the case, he might as well do some practice on this spring; can't make it worse. Then when he finds a good balance assembly he can replace it.

    But, it raises an interesting point (and slight change of subject) for which I have no right answer.

    Suppose it was yours, and you could find a donor RR grade Elgin 16s with gold screws and a good spring. Is it "right or better" to change it? Mike's Grade 453 uses a 2532C staff; which is used in other models. So if he gets past thinking Veritas, he could expand his search for the donor. Of course, it takes some research on his part to find which grades are suitable candidates, but would you approve of this? Should the alteration be documented in the watch?

    Just opening the can of worms.
     
  21. MikePilk

    MikePilk Registered User

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    The can of worms is already open ! When I got the movement this was the balance fitted -
    20150925_175217.jpg 20150731_144255.jpg

    It needed a new balance staff, and as it was my first Elgin I didn't spot the obvious error - a friction fit shaft. The balance was from a Waltham!
    The rollers had been jammed on at odd angles to make it work.

    I spent months looking for suitable donor parts - I bought 2 B.W.Raymond 19J movements, but they turned out to be far too good to use for parts.

    I did eventually find a 19J B.W.Raymond for parts, with what should be the correct balance. (I also need parts for the other Raymonds, on one the escape wheel teeth are worn completely down!). That's the balance I'm using

    I happened to search on ebay last night for 'Elgin hairspring #796, strength 2' - and found one 'as new'. Amazed at that !
     
  22. Rob P.

    Rob P. Registered User

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    IMO, I would use ANY 16s Elgin balance which I could fit onto the staff. Today, given that parts are getting scarcer and scarcer, the idea of waiting until the 'perfect' part comes along is ridiculous. If a substitute part is available and will make the watch run, then use it. Originality can be taken too far when rebuilding a movement.
     

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