CAUT

  • 1.  Vise grip on bridge pins

    Registered Piano Technician
    Posted 01-19-2020 09:27
    Some time back someone mentioned clipping a vise grip on the bridge pins of a note that didn't ring out like those around it.
     
    I can't find the old email, and searching didn't get me anywhere. Can someone please tell me what it means if this test improves the note, and what the fix is?
     
    thanks,
    Aaron
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    Aaron Bousel
    Registered Piano Technician
    413-253-3846



  • 2.  RE: Vise grip on bridge pins

    Registered Piano Technician
    Posted 01-19-2020 12:22
    Try searching again with the topic "riblets" The visegrip test tells you the soundboard needs more weight or impedance. Riblets were proposed a few years ago in an article in the journal by Darrel Fandrich to address this problem. It worked well for me more than once. Good luck!

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    WilliamKeller
    bkeller3@verizon.net
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    Original Message


  • 3.  RE: Vise grip on bridge pins

    Posted 01-20-2020 12:54
    Here's a link to a Thesis on Soundboard Voicing....from 2009. I posted this link before in the old Riblets discussions found.

    Booth weights and riblets are discussed in
    this article. You can read the abstract which
    might tell you all you want to know or download the entire Thesis...free.

    I'm looking at putting riblets on a D that
    seems to go short on fundamental and sustain
    at E4....below it is nice, but right up in
    there through that break it's a bit short.

    Getting to the board with a double dampchaser
    installed might be "fun"!

    --
     Richard Adkins 
     Keyboard Tuning and Maintenance
     Curator of Instruments 
             
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    Original Message


  • 4.  RE: Vise grip on bridge pins

    Registered Piano Technician
    Posted 01-20-2020 14:01
    Just keep in mind that adding mass is not the same as increasing stiffness.  Different parts of the piano may be compromised for different reasons.  Most pianos become compromised due to loss of stiffness not decreasing mass.  Adding mass slows down velocity in a different way than added stiffness (though I'll have to let the engineers or quasi engineers give the explanation).  Adding mass can be somewhat effective if you build the soundboard too stiff, especially in the treble, and the inability for the strings to transfer their energy to the board results in jangling of the front duplex.  Adding mass can also be somewhat effective where end of the bridge effect is troublesome (though it can also create a timbre that is a bit weird). But as a remedy for loss of sustain in a board that is compromised due to lack of stiffness that accompanies loss of crown I don't find it that effective.  The placebo effect, however, is quite real.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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    Original Message


  • 5.  RE: Vise grip on bridge pins

    Registered Piano Technician
    Posted 02-07-2020 18:03
    I just went through this with my own piano, a 1908 Stwy O. The fundamental on E5 took a nose dive while the partials above stayed steady (and matched the neighboring notes). The fundamental's sustain was no shorter that its upper siblings. It just immediately ducked down to a volume more like at the end of decay. I clipped a 4" vice grip on the meat-side bridge pins, and the "premature decay" disappeared. Encouraged, I fastened a lead bar (1/2x3/8x6") to the rib, directly below that note's place on the bridge and the improvement is now permanent.

    Two weeks later I tried it on a D whose C7-D#7 was lost in the fog. Neither the vice grip nor the weight underneath made a difference

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    William Ballard RPT
    WBPS
    Saxtons River VT
    802-869-9107

    "Our lives contain a thousand springs
    and dies if one be gone
    Strange that a harp of a thousand strings
    should keep in tune so long."
    ...........Dr. Watts, "The Continental Harmony,1774
    +++++++++++++++++++++
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    Original Message