Ansonia Round Movement - Original Mainspring

Discussion in 'Clock Repair' started by MuensterMann, Apr 8, 2017.

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  1. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Hello, I have a round Ansonia movement from a Royal Bonn clock. I am replacing a mainspring (that is not original) and I would like to find out what the original mainspring sizes were for this movement. Does anyone have this in their records?
    [​IMG]
     
  2. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    You haven't tried measuring the original?

    Somebody made a real mess of that back plate.
     
  3. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Yes, I have measured what is on this clock now. However, I would like to know if anyone has the original measurements - since what is on this clock now are not the originals. Instead of loop ends, they used hole ends and attached to the posts via wire. Thanks!
     
  4. roughbarked

    roughbarked Registered User

    Dec 2, 2016
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    I see., now. :)
     
  5. Willie X

    Willie X Registered User

    Feb 9, 2008
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    They look about right. Will the clock run in this condition? If yes, let it run to see how these springs work. If they work OK, just get loop end springs of the same dimensions.
    That looks like a crack on the 7th coil in, just beneath your thumb.
    Willie X
     
  6. MuensterMann

    MuensterMann Registered User

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    #6 MuensterMann, Apr 8, 2017
    Last edited: Apr 8, 2017
    Well, the one broken spring (yes, one of them was broken) seems to be .44 inches wide, a thickness of .012 or .013, and a length of 106 inches. I wonder how close this is to the original.

    I do not find anything close to this size out in the market!
     
  7. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    I am hoping that what I have is way off - since I cannot find that size mainspring. Save me!
     
  8. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Upon re-measurement I found that I made a mistake in saying the length was 106 inches. It is really about 80 inches (I had to add two broken pieces).

    Thus, the present mainspring (not original to the movement, since it is hole end) is 7/16 inches wide (11mm) x .12 or .13 inches thickness x 80 inches length. I could not find this size mainspring. However, there is a 9mm wide, .012, x 83 inch loop end. Would 9mm width instead of 11mm width be a problem for me?

    Otherwise, there is a hole end that is 10mm wide x .012 thickness (strength) x 73 inches long. In this case I would have to do what the last repairman did to attach the mainspring to the post.

    Help!
     
  9. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Why not anneal the spring and wrap it around the post.
    You have two options. You can punch a hole and rivet it
    or have a tail that tucks under the last 1/2 turn of the
    spring and then wraps around the post.
    It will keep the spring from coming off.
    Tinker Dwight
     
  10. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Tinker, are you referring to the reuse of the spring I have? If so, it is broken with the longest piece being 55 inches.
     
  11. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Well then,
    hunt for a spring with the right thickness and width.
    Don't worry about the end.
    I have one clock with the end folded as I described
    it works fine but waste some of the length.
    Tinker Dwight
     
  12. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    The present mainspring (not original to the movement, since it is hole end) is 7/16 inches wide (11mm) x .12 or .13 inches thickness x 80 inches length. I could not find this size mainspring. However, there is a 9mm wide, .012, x 83 inch loop end. Would 9mm width instead of 11mm width be a problem for me?
     
  13. Tinker Dwight

    Tinker Dwight Registered User

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    You could try it but watch for it jamming at
    mid wind where the spring would tend to come
    out sideways.
    Tinker Dwight
     
  14. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    New information! The remaining mainspring has a crack and it is ready to break complete. It seems that this is the original spring with a loop end. The length is indeed 105 inches, the width is 11mm, and the strength is .012 inches. Where can I find this size mainspring? Or, something close that will work? Or, is there a modern movement that I can substitute? I notice that older Royal Bonn movements were not round and the round ones are hard to find. HELP!
     
  15. THTanner

    THTanner Registered User
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    I would find the closest I could get new, loop or hole, that is the same width, strength and a bit longer than 105. then cut it down to size, anneal the end and create a loop.

     
  16. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Looking at Timesavers, Ronnell, and Merrits supply - there is nothing even close.
     
  17. bruce linde

    bruce linde Technical Admin
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    Nov 13, 2011
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    mm -

    i really wanted to help, but all i could find was this:

    on the royal bonns, everyone seems to report that the mainsprings had been replaced with 7/16.
    my impression from other threads is that slightly under-powered is preferable to over-powered... yes?

    i was also curious as to your impression of whether 9mm would work... do you think it would be too narrow? what would be your best guess at the ideal spring width?
     
  18. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Yep, the length is going to be the problem alright. You could go shorter, by about 10% without any problem. But that still doesnt get you in the ballpark of what's available. You may not have much choice except to try that 9mm spring. Sometimes a narrow spring will get wonkie on winding, sometimes they don't.
    Willie X
     
  19. Tinker Dwight

    Tinker Dwight Registered User

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    Rather than measuring the width of the spring, how
    about measuring the width of the opening for the spring.
    We don't even know if the spring is the right width.
    There are a number of 9.5mm springs that might work as well.
    Being narrower, they could be some thicker and not be as strong.
    I wonder if anyone has ever use a belt sander on a spring.
    Tinker Dwight
     
  20. shutterbug

    shutterbug Moderator
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    If you could avoid excessive heat, I think that might be worth trying. Coil the spring tight, and take some off each side to keep the holes centered.
     
  21. Tinker Dwight

    Tinker Dwight Registered User

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    I think you'd need to clamp it with a board in the back to keep the
    spring from having the center push out.
    Tinker Dwight
     
  22. THTanner

    THTanner Registered User
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    I think I would lay it flat on wet/dry 100 with water on a flat steel sanding block - work it in circles on both sides. I have a vibrating steel sanding table that I use to work steel parts like that, but I have never worked a coiled spring.

     
  23. bruce linde

    bruce linde Technical Admin
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    if you left one side alone, you'd have a way of making sure the sanded side stayed true, yes?

    you could then smooth out the results with 600/2000/4000, just like pivots (at least, that's how i do them).
     
  24. THTanner

    THTanner Registered User
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    I do think you need to sand both sides - but certainly keep one side true until the first sanded side is finished and checked carefully. If the spring is wound tightly and a sanding block is placed on top of the spring to maintain even pressure across the whole coil it should be possible to keep the middle from bulging up. I wooden rod through the sanding block and down into the spring would keep it centered under the block. The main issue with this or a sanding belt will be to keep even pressure on all areas of the spring. Sanding more slowly by hand on the sanding plate and rotating the spring often is less likely to sand unevenly. I am not sure how important sanding the edge of the spring metal would be with finer grit, but I would certainly unwind the spring and clean up the sharp edges left by the sanding. The only time I have sanded a spring like this is when I remade the center hole portion after annealing. I filed then sanded the curled end to taper it. I have never tried to sand the rest of the spring that is not annealed. Perhaps there are issues with doing that and creating little cracks along the edge? Maybe someone has some experience with that.

     
  25. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Placing the width of the mainspring across the available space on the arbor it matches perfectly. The width is correct at 11mm.
     
  26. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    I resolved my problem by finding an orphaned similar movement. One spring was 105 inches and the other 85 inches in length.

    Were Royal Bonn clocks made throughout the 1900s? Does anyone know how old my clock may be based on the round movement?
     
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