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Odd Tuning Stability

  • 1.  Odd Tuning Stability

    Posted 02-28-2025 07:23

    (I should have said "tuning instability.")  I tuned a '70s Yamaha G3 the other day. I'd sold the piano, and it had been about 3 years since the owner had it tuned. Anyway, it was not very far off pitch, but the upper tenor section was a dog to tune (the third of the four divisions between the plate struts). The pins seemed tight enough, but every time I raised the pitch in that section, it almost immediately dropped. I re-tuned, and the same thing occurred. The plate and bridges look good, with only a minor SB crack. The pins were not newly-tight, but no different than on the rest of the piano. This occurred only in this one section. Not having my big screwdriver bit, I was unable to tighten the rim screws. However, I'm thinking it must be the tuning pins, but they are not visibly moving when my hammer is in place. I noticed no problems when I had this piano in my shop. Any ideas?



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    Philip Jamison
    West Chester PA
    (610) 696-8449
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  • 2.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 02-28-2025 07:39

    But you eventually got it to settle down...yes?

    I think I would want to go back in about a week or so just to check it abdvsee if it was holding.

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 3.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 02-28-2025 07:39
    If there is tuning instability, the first thing I would do is tighten the rim bolts. 

    I took a Samick grand in trade for a lady who bought my rebuilt Steinway. She had complained for years to her tuner that her piano wouldn't stay in tune. (I was not the tuner). The first thing I did was tighten the rim bolts. Most were tight, but I was able to tighten a couple of bolts in the bend just a few notches. I tuned the piano and after I sold it, and for several years the tuning was stable. \

    Wim





  • 4.  RE: Odd Tuning Stability

    Posted 02-28-2025 09:03
    Thanks, Wim. I'll try to put a big screwdriver in my kit. I left my other one somewhere.

    Phil



    Original Message


  • 5.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 02-28-2025 10:08
    It might need more than just a big screwdriver in your hand. I had a 12" long square shank screwdriver that I used with a crescent wrench to get the most torque. 



    Original Message


  • 6.  RE: Odd Tuning Stability

    Posted 02-28-2025 11:58
    I use a large bit that fits my ratchet wrench. I can't seem to find a regular screwdriver with an end wider than 3/8 inch.


    Phil



    Original Message


  • 7.  RE: Odd Tuning Stability

    Posted 03-02-2025 01:03
    Hi Phillip,
    I would be suspect of the pinblock to flange fit in that section, I have seen this in Yamahas and others, with identical symptoms. A mirror and biz card(s) should reveal if there is a problem.
    If there is, some shimming would be in order, perhaps lowering the tension in the section first. I would consider this an easy, no harm treatment. Maple shims glued on the pinblock side, tapped up in place, then cut off anything proud on the bottom. 
    Hopefully this is helpful, 





  • 8.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 03-02-2025 12:47

    I would recommend checking the flange fit with a .001 feeler guage as well.  You would be surprised at how many pianos are poorly fit - both new, old and rebuilt.



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    Parker Leigh RPT
    Winchester VA
    (540) 722-3865
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    Original Message


  • 9.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 03-02-2025 12:54

    Greetings,

    You will most likely find a gap between the pinblock and the plate flange. Not doing that fitting is often by design. More than one piano maker seems to rely on two hundred and thirty some-odd tuning pin plate bushings to perform the same function as fitting the block to the flange. Not than shimming or epoxying the gap won't help. It should.

    Let us know what works in this case!

    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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    Original Message


  • 10.  RE: Odd Tuning Stability

    Posted 03-02-2025 13:08
    I have heard this reasoning of tuning pin bushings acting as a fulcrum and pulling the pinblock toward the stretcher thus negating the need for a good flange fit. This does not sound like a stable system to me. 
    The block should fit top, bottom, left, right, front and rear from my experience.



    Original Message


  • 11.  RE: Odd Tuning Stability

    Posted 03-02-2025 15:32

    I'll definitely check the flange fit and tighten the plate screws. I left it pretty much in tune, so they may or may not call me back!

    Phil



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    Philip Jamison
    West Chester PA
    (610) 696-8449
    ------------------------------

    Original Message


  • 12.  RE: Odd Tuning Stability

    Posted 03-02-2025 15:37

    Some years ago I had reason to pull the plate of a Kawai RX-2, checking for water damage.

    There was an intentional gap along the front, vertical faces of the plate and block.

    At the top inner corner of the plate there was a carefully shaped extra step which fitted neatly into a notch along the corner of the block.

    The fit was exquisite. But if someone did the business card diagnostic they would have concluded that the entire front edge of the plate/block fit was gapped.



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    Ed Sutton
    ed440@me.com
    (980) 254-7413
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    Original Message


  • 13.  RE: Odd Tuning Stability

    Registered Piano Technician
    Posted 03-03-2025 07:31

    Unless I missed it, no one mentioned the plate webbing screws holding the pinblock in place. 

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
    ------------------------------

    Original Message


  • 14.  RE: Odd Tuning Stability

    Posted 03-03-2025 09:54
    Hi Ed, I also have seen this on a stepped block and would tend to agree that if the block fits well along its length, especially if that is along the top near the webbing, things should good enough. While this may be by design, I would ask if it is simply a cost cutting measure. 
    I recently created a new block for a vintage Weber ( also mortised into the sides ) , this block had 3 steps including a bass cap. Thank you Christian Bolduc for your instruction on fitting a mortised block.



    Original Message