Pianotech

  • 1.  Shift Clunk

    Registered Piano Technician
    Posted 21 days ago
    I am paying closer attention to the shift mechanisms on our collection of university pianos, and am noting various squeaks, whooshes, clicks and clunks.  I have found some very helpful journal articles (using the preliminary index produced by Fred and Jeannie) regarding the hunting down and solving of issues arising from friction, but nothing addressing the percussive clunk that sometimes occurs at either end of travel of the key frame.  One suggestion from Roger Gable, concerning installing a capstan under the keybed to limit shift lever travel (to be adjusted to reinforce the function of the stop screw that meets the end of the keyframe) might help at the right end of keyframe travel, but what suggestions do you have to mitigate a loud clunk that occurs on the sudden release of the shft pedal?  Other than instructing the pianists to pedal more intelligently . . .   Not that anyone has been complaining.

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    Floyd Gadd
    Regina SK
    306-502-9103
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  • 2.  RE: Shift Clunk

    Member
    Posted 21 days ago
    First of all is this on a particular model and brand of piano and how old are the pianos ? Have you traced where the sound seems to come from and at what point in the travel ? it sounds like it is at both ends of the key frame travel . I am thinking the felt stop inside the action cavity could be the source. I have seen that worn down so far it is like a piece of veneer and useless as a sound reducer. Other issues could be the position of the shift mechanism in the keybed slot or even contact underside the keybed where the lever is position. On some pianos the spacing is very tight and there is contact with the trapwork levers. I would try to break the problem down into manageable pieces and try to correct the sound on one side. Often times sounds throw you off because they get transmitted and amplified or they have multiple layers.

    Perhaps its time to explore using things such as acoustic foams, hard rubber blocks and other noise reduction methods. The appliance industry has learned to reduce the noise of dishwashers, washer machines, dryers by using rubber grommets, foams and blocks between components. I replaced the food grinder in my sink with one that had a rubber gasket flange that isolated it from the metal sink. Huge noise reduction.

    BTW the sound can also becoming from the sudden pedal release and starting in the pedal box or a loose lyre and lyre brace

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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    843-325-4357
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  • 3.  RE: Shift Clunk

    Registered Piano Technician
    Posted 20 days ago
    Thanks Jim.  Eleven pianos in question here.  Three 1996 Yamaha C2s, one 2000 C1, one 1965 G2, two mid-70s G1s, a couple of mid-70s Bösendorfer 200s, and a couple of 1988 Young Chang G-185s.  While there are various noises to deal with, the one I'm asking about is the percussive thump when the left end of the key frame meets the stop block on the side of the action cavity.  The fabric/felt there will be compressed, given the age of these instruments, but I would not anticipate wear from friction.  Is replacing the material on the surface of the stop block going to solve the issue?  If so, is there a specific material you would recommend?  I don't think we want anything too squishy.

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    Floyd Gadd
    Regina SK
    306-502-9103
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  • 4.  RE: Shift Clunk

    Member
    Posted 20 days ago
    I will have to look up what type/thickness felt would be appropriate. There is no friction involved since it is the frame coming back to the block mounted to the rim. An examination of a new/near new piano may reveal what the felt should look like. Keep in mind you cant put something in there that will not allow the frame to be put back in. On the right side where the spring is the spring may not be strong enough at keeping the frame away from the rim and providing space. If the spring has weakened from years of play and the action frame being removed and replaced the frame may be pressing the spring into the rim . Some new felt on the stop block may shift the action off enough you will have to realign hammers to the strings or adjust the stop screw. I recently had to order a new lyre for a Yamaha G2 that had been used as a pet pee post. I have an xray view of most of the parts and will see if there is a new stop block part number. You could get lucky or have to wait months. The G2 needs new caster wheels which may take 3-5 months !!!
    I looked up some of your piano models and there are different part numbers and descriptions for the keyframe stop blocks The part number for the block is T5591710 for models C1-C7 ; GP Key Frame Back leather T5591700 covers the block; Flat head wood screws secure the block part EP724106 6 pack Keyframe shift spring T5592400; flat head screws for spring part # EP745256; keyframe stop punchings T5591616 -CAUTION there are another set of parts that have different pictures and parts numbers so I advise talking to Yamaha Parts. It is important to have the serial number for each piano


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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    843-325-4357
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  • 5.  RE: Shift Clunk

    Registered Piano Technician
    Posted 20 days ago
    It seems that you could easily check this, Floyd. Insert a strip of whatever felt/cloth in front of the stop block to hear if that stops the objectionable noise.
    An excessively strong return spring can also slam the action back against the stop, making extra noise. Of course, the pianist is responsible for operating the pedal. If the noise test is simply pressing the left pedal and abruptly letting it go, there will necessarily be mechanical noise. But that isn’t how the pedal is normally operated while playing the piano, is it?

    Bob Anderson
    Tucson,AZ