Edinburgh fusee mainspring problem

Discussion in 'Clock Repair' started by klokwiz, Nov 9, 2018.

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  1. klokwiz

    klokwiz Registered User
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    Hi, I think I have this sorted out but would like a confirmation since I am new to fusee clocks. The chain in this one will not wind far enough on to the fusee to contact the limiting arm to set it into place to end the wind.

    I have let down the mainspring to check preset to see if it was too far mound causing spring to be used up. It was not, it was loose allowing the chain to sag at end of run. so it appears to me that this was issue for prior repairperson.

    What is happening is at the end of the wind it is running out of spring. there appears to be chain enough to complete wind onto fusee, but the spring is tight in barrel. My assumption is the spring either broke and was shortened or replaced with one too short.

    I will be verifying the chain length when I next take it apart, and will then inspect the spring in barrel.

    posted photo shows chain at end of wind with spring pulled taught.

    questions: 1) am I likely right about mainspring? 2) how much chain should be remaining on barrel at end of wind? 3) if I need a new spring where can I best source one? (since these are so different from most)

    movmt back plate.jpg movmt frt.jpg movmt fusee and barrel.jpg movmt fusee ans barrel2.jpg movmt fusee1.jpg movmt1.jpg
     
  2. shutterbug

    shutterbug Moderator
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    The fusee needs a little pre-wind, and it's possible that the former repairman went overboard with it. Unless the spring or chain is too short, as you suspect, that will be the issue. Let us see what you have when you take it apart.
     
  3. bruce linde

    bruce linde Technical Admin
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    I think you are correct in that the spring broke and was repaired/shortened at some point.

    There should be enough chain left after a fall mind so that it’s wrapped partially around the barrel enough to not pull on the hock

    Replacement chains are somewhere around 90 bucks, whereas mainsprings are probably around 20 to 30… Timesavers
     
  4. bruce linde

    bruce linde Technical Admin
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    If he let the mainspring all the way down before the end of his incomplete wind then the mainspring is too short... but yes indeed, open her up and see what there is to see! :cool:
     
  5. klokwiz

    klokwiz Registered User
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    Bruce,

    Yes that was first thing I did to see if too much spring was being used up. I set it to one turn as I have for my other fusee's and the wind is even shorter. pretty sure as you have said the spring was shortened.

    Have you had good experience with the timesavers springs this size?

    Joe
     
  6. shutterbug

    shutterbug Moderator
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    Just make sure they don't send you one made in India. Too many of those break prematurely.
     
  7. bruce linde

    bruce linde Technical Admin
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    On my last one I popped a little more for the German one and was very pleased with the quality… Not that I’m an expert
     
  8. klokwiz

    klokwiz Registered User
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    Bruce,

    was the german one from timesavers? and if so does it state where made in their catalog?

    Joe
     
  9. bruce linde

    bruce linde Technical Admin
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  10. klokwiz

    klokwiz Registered User
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    Bruce,

    thanks for that link, I have a devil of a time finding stuff on their site for some reason.

    Joe
     
  11. bruce linde

    bruce linde Technical Admin
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    effing spell check... that should have been 'after a full wind' (and not 'fall mind'). :cool:
     
  12. shutterbug

    shutterbug Moderator
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    That's pretty funny, Bruce! I had to read it again because my mind read it correctly the first time! The mind is an amazing thing!
     
  13. bruce linde

    bruce linde Technical Admin
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    when i'm not at my desktop machine i sometimes dictate my responses into my iPhone or iPad for transcription convenience, but then get misheard words, oddly placed capitalizations, etc.

    ah, computers. :cool:
     
  14. klokwiz

    klokwiz Registered User
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    Hi, got around to taking the mainspring out. As we discussed it appears the spring has been shortened at the barrel hook end. The spring removed is 34.75mm wide but my barrel depth is 39.9mm,so It would appear that the spring is also too narrow. The replacement mainsprings on timesavers measure 38mm which would appear to allow ample clearance in barrel, next size down is 35mm next up is 41mm. when I plug the barrel and arbor measurements into the in-barrel spring calculator on site it comes up with 88.5inches length.

    measurements: barrel outer dia 57.5mm / 21/4", inner diameter 52.5mm / 2 3/32", arbor dia. 13.5mm / .5315", spring thickness .45mm / .0177

    so my two questions are:

    1) is 2mm clearance ok in barrel for spring side to side, so I should correct what I perceive as it having incorrect spring width.
    2) is barrel diameter measured only as inner diameter as in calculator. my outside diameter is 2 1/4" which would mean I need the next size longer spring.

    thanks for your feedback,Joe
     
  15. Uhralt

    Uhralt Registered User
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    The 2 mm clearance should be ok. The barrel diameter is measured from the inside because that is the place where the spring will be located and defines the maximum possible expansion of the spring. I'm surprised that the difference between inner and outer diameter is that large. Is the brass tube of the barrel that thick? I would definitely measure the spring that you have to make sure that the new one is sufficiently longer to allow the fusee to be fully wound. The chain on the last three turns of the fusee causes the break lever to be engaged.

    Uhralt
     
  16. klokwiz

    klokwiz Registered User
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    Uhralt,

    thanks for the confirmation on the spring clearance. yes the tube wall is 2.5mm which is the 5mm difference. I will measure the length as you suggested. the chain turns the barrel one full turn to take up the rest of the fusee.

    thanks joe.
     
  17. Uhralt

    Uhralt Registered User
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    Your new spring must be at least 16.5 cm (6.6 inches) longer than the old one. This is the length of the piece of spring at the wall of the barrel needed for a single turn.

    Uhralt
     
  18. klokwiz

    klokwiz Registered User
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    Uhralt,

    I measured the removed spring. it is 74 inches long. 14 short of replacement I have ordered (88.6") and should do the job by all calculations.

    thanks for your interest and help.
    Joe
     
  19. Uhralt

    Uhralt Registered User
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    Yes, that one should work well!

    Uhralt
     
  20. klokwiz

    klokwiz Registered User
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    hi. got the replacement spring in from timesavers. it is a good quality spring the listing said german made but it was not marked as such. installed the spring in barrel and tested the fusee chain for correct length and locking. the spring has corrected the problem. thanks to all who replied. joe
     
  21. Uhralt

    Uhralt Registered User
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    Great! Thanks for the feed back!

    Uhralt
     
  22. klokwiz

    klokwiz Registered User
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    Hi, posting photo barrel and chain in correct fully wound position with lock in place after new spring was installed. After cleaning the movement to install new spring I found a note scratched in movement that the spring was three turns short, amazing what people will do instead of fixing it properly. I also am showing my spring and the foot release method used. I looked up an old post here and got the idea there. the spring was so big I was concerned about cutting the retaining wire. I placed spring in old towel folded it over placed my foot on it lifted edge of towel to see wire and cut it with my foot holding down on the spring laying on its side. once the wire was cut letting pressure off the spring it unwound safely under the towel. Joe

    barrel and fusee chain with locking pawl.jpg barrel lock with short spring note.jpg replacement spring in wire retainer.jpg spring released with foot method.jpg
     
  23. Uhralt

    Uhralt Registered User
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    Good method to release the spring! The new spring looks like it is good quality. It appears to be polished and shiny.

    Uhralt
     
  24. klokwiz

    klokwiz Registered User
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    Hi, updating this post as I have changed the spring size. If any of you have been following my other fusee spring post it became apparent that maybe the replacement spring was too strong. After installing the above mentioned spring this clock seemed to take a lot more force to wind. Since the replacement spring was wider I felt that maybe this was the reason it was harder to wind. The replacement spring is the same thickness as the one removed but was nearly 5mm wider. I have changed the spring to a spring the same width as the original and the clock seems to wind easier. As it is quite subjective whether or not it is easier, I am pretty certain it made a difference. As you may recall from the earlier information my original replacement spring fit the full width of the spring barrel 41mm or 1 1/2". The removed short spring was about 36mm or 1 3/8, I made the assumption that maybe the short original spring had been fitted as a handy substitute and was not only too short but also too narrow. In hindsight it appears to me that the spring broke and was shortened then reinstalled. Since I have no way of telling for certain if this was the original spring I do not know if the width is as originally intended. But this has been a fairly expensive experiment in repair since the springs are not cheap. Joe.
     
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  25. Uhralt

    Uhralt Registered User
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    At least a happy ending!

    Uhralt
     

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