Pianotech

  • 1.  Tight balance rail bushing

    Registered Piano Technician
    Posted 08-15-2018 09:58
    Anybody else had this?
    This time, it’s on a Kohler and Campbell 600: key buttons too hard to squeeze, even with compound leverage pliers; already-thin key bushing cloth you can’t iron any flatter - this isn’t the first time or the first brand where I’ve encountered this annoying scenario.
    What have others done about it?
    Thanks,
    Linda Scott

    Sent from my iPhone


  • 2.  RE: Tight balance rail bushing

    Registered Piano Technician
    Posted 08-15-2018 10:06
    I used to have to ease keys on some Chinese pianos where the keys were made of plywood. I modified a pair of Vise-Grip pliers to do the job. I ground the tips of a regular pair so that they would enter the average slot size in the key. I don't know what kind of wood you have there, but likely it's some kind of hardwood. You could also use some heated cauls to iron the felt, rather than crush the wood.
    Paul McCloud
    San Diego

    Linda Scott:
    Anybody else had this?
    This time, it’s on a Kohler and Campbell 600: key buttons too hard to squeeze, even with compound leverage pliers; already-thin key bushing cloth you can’t iron any flatter - this isn’t the first time or the first brand where I’ve encountered this annoying scenario.
    What have others done about it?
    Thanks,
    Linda Scott




  • 3.  RE: Tight balance rail bushing

    Registered Piano Technician
    Posted 08-15-2018 10:39
    As Paul has said, a key easing iron with an appropriate size broach would be my first go-to attempt to remedy this situation.

    Alan

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    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
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  • 4.  RE: Tight balance rail bushing

    Registered Piano Technician
    Posted 08-16-2018 09:12
    Thanks - but what I tried to convey was that I tried easing by ironing with the heated caul first, but the felt was already so thin and so flat that no durable easing was obtained by that means, and that's what made this set of keys so unusual.  I guess the vice grips idea is worth exploring - thanks.
    Best,
    Linda


    Linda Scott
    pianositter.com





  • 5.  RE: Tight balance rail bushing

    Registered Piano Technician
    Posted 08-15-2018 10:43
    Linda,

    Have you also checked the BR holes? Sometimes too tight holes (or not wide enough at the top of the hole) can masquerade as (or aggravate) a slightly tight bushing.

    Otherwise, I would suggest treating the bushings with Teflon powder (or a drop of VS Profelt) and use an appropriate metal key bushing caul (heated) to size them.

    If you happen to already own a Key Bushing Iron that may work better. Pianotek has it with both tapered tips and straight tips. I would probably choose a straight tip in a case like this.

    IOW treat the cloth, not the wood in this case. At any rate I would try one or two in different ways to see what works best.

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 6.  RE: Tight balance rail bushing

    Posted 08-16-2018 11:53
    Look inside the balance rail mortice. Since it has very thin bushing cloth, the pin might be rubbing on the side of the mortice. Last week, I expanded the mortices on the front and balance rails on a Samick product. I used a football shaped bit in a Dremel Tool to remove material.
    I've had to do this once or twice before.

    Also check the height of the balance rail hole.

    Other than that, brute force will compress the hard buttons.

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    Regards,

    Jon Page
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