Help Mainspring mystery or maintenance installed problems

Discussion in 'Clock Repair' started by Icee3, Jan 21, 2020.

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  1. Icee3

    Icee3 New Member

    Jan 21, 2020
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    I have a Unghans B26 279 Westminster chime in a grandmother cock. The time mainspring has always been difficult to wind. It seems to be too stiff. The clock would run fast and about mid week run correctly and by friday run slow. I removed the barrels and springs, the springs are new. The time spring is much shorter and stiffer than the strike. I ordered and replace the time spring matching that of the strike spring. Now, it does not have enough power to run. Any idea to the correct size for this clock?
     
  2. Dick Feldman

    Dick Feldman Registered User

    Sep 1, 2000
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    Your original symptoms are of a worn movement, not of a misapplied main spring.
    Springs seldom go bad and the original spring likely was correct.
    If you changed something in the movement, you probably added a second reason the clock is not operating reliably.
    Two things wrong with a movement are much harder to solve than one.
    Do you have the cart pushing the horse?

    Dick
     
  3. Icee3

    Icee3 New Member

    Jan 21, 2020
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    Well, the clock was recently bushed. Im guessing the clock was repaired years ago with the wrong spring and then another repair to the bushings to take care of the created problem. I do know what you are saying though. The movement looks to be in good repair just didn't keep time and the spring was very stiff . My wife could not wind the mainspring on this clock leading me to believe the wrong spring was installed to deal with the worn bushings.
     
  4. Dick Feldman

    Dick Feldman Registered User

    Sep 1, 2000
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    “Well, the clock was recently bushed”
    Does that mean all of the pivot holes were bushed, only the holes necessary to make the clock run were bushed, or a couple of bushings installed? To be dependable, the verge and escape wheel must have consistent and sufficient power. Each of the three conditions above will/can give different results.

    “Im guessing the clock was repaired years ago with the wrong spring and then another repair to the bushings to take care of the created problem.”
    Two things determine the function of the main spring. The thickness of the spring will determine how much force is applied to the train and the length of the spring will determine run time. What size spring did you install and what size came out with the last repair? If you give a diameter and width of the spring barrel in question, an approximate size spring can be determined for a reasonable fit.

    “The movement looks to be in good repair just didn't keep time and the spring was very stiff .”
    Was this a simple visual inspection or did you actually check the play on each and every pivot hole? A “stiff” spring would indicate a spring that is/was too thick.
    Installing a heavier spring is an inappropriate solution for a worn movement. Were the bushings installed by you or someone else?

    As always, pictures of the movement will be helpful. Close up, clear pictures of the front, rear, sides and the parts in question. It is difficult to trouble shoot a problem without all sorts of information.

    Your symptoms still are of either a worn movement and/or a mis sized main spring. Maybe you have both problems which will make a solution a bit tougher.

    Best,

    Dick
     
  5. shutterbug

    shutterbug Moderator
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    Oct 19, 2005
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    Typically, you have the strongest spring on the chime, and the weakest on the strike. The strike and time springs are often the same, but also often different. Yes, pictures of what you have would help.
     

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