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Pinblock to Plateflange Mating

  • 1.  Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 16:24
    How critical is pinblock to flange mating with regards to tuning stability?

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    Wesley Hardman
    Owner Hardman Piano Service
    Scottsboro AL
    256-574-4761
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  • 2.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 16:30
    I'm confused!  What "flange"? 

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    Paul T. Williams RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska
    Lincoln, NE 68588-0100
    pwilliams4@unl.edu

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    Original Message


  • 3.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 17:04
    There is quarter inch gap between the plate and the pinblock. 

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    Wesley Hardman
    Owner Hardman Piano Service
    Scottsboro AL
    256-574-4761
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    Original Message


  • 4.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 17:14
    It's critical.  What kind of piano?  how old? etc.  wondering where the term "flange" comes in?  that is a term usually associated with a terminated piece from which a moving part of some sort rotates. Pinblock to plate is just that and must be solid or either the pinblock is shot or the plate has "warped" in some way.  It's usually the pinblock. Plates don't really warp, unless cracked.

    Pin block must be mated to the plate at all cost.   It sound dire.  Please give more details.

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    Paul T. Williams RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska
    Lincoln, NE 68588-0100
    pwilliams4@unl.edu

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    Original Message


  • 5.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 19:58


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    Daniel Berg
    Orlando FL
    407-884-1814
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    Wesley sent this from our meeting for Central Florida he attended showing us the benefits of using my.ptg.org. The piano in question is new and all the grands I have seen have about 1/4" gap between the plate flange and pinblock from bass to treble. Apparently this manufacturer has decided to proceed with this design for now.

    flange
    flanj/
    noun
    1. 1.
      a projecting flat rim, collar, or rib on an object, serving to strengthen or attach or (on a wheel) to maintain position on a rail.
      "the flanges that held the tailpipe to the aircraft"





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  • 6.  RE:Pinblock to Plateflange Mating

    Posted 03-14-2014 10:37
    The term 'flange' would, to a pianotech, usually mean that small wood block thingy with a pin through it. But in the real world that Flange has much greater use. It can mean a 'ridge' on a larger plate and at right-angles to it. My definition. In engineering terms there are 'shoulders', 'faces' and flanges &c. it is even used in the recording world - 'Flanging' as a particular effect. Interesting....  Michael (UK) 

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    Michael Gamble
    semi retired
    Brighton
    01273813612
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    Original Message


  • 7.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-14-2014 10:49
    Good to know! Thanks

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    Paul T. Williams RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska
    Lincoln, NE 68588-0100
    pwilliams4@unl.edu

    -------------------------------------------






    Original Message


  • 8.  RE:Pinblock to Plateflange Mating

    Posted 03-14-2014 08:52
    Wesley
    In my younger days when fitting a pin block to the flange I sometimes filled the void between the flange and pin block with fiber glass resin or might elect to place pin block shims in the void. At any rate I was taught to fit that pin block as tight as possible against the plate. Today there may be better materials available to fill the void.

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    Thomas Black
    Decatur AL
    256-350-9315
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    Original Message


  • 9.  RE:Pinblock to Plateflange Mating

    Posted 03-15-2014 10:44
    If this is a Kawai piano, the engineering may be more complex than you are understanding.
    In certain Kawai pianos, the top rear edge of the pinblock is fitted very carefully to a small "step" at the corner of the inner faces of the plate and flange. Below that, along the back edge of the block, there is space.
    perhaps Don Mannino can explain better.

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    Ed Sutton
    Editor
    Piano Technicians Journal
    ed440@me.com
    704-536-7926

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    Original Message


  • 10.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 20:55
    Wes

    The pin block should contact the flange every inch or so. It doesn't need to be a flush fit all the way from one end to the other, but there certainly should not be any gaps as big as 1/2" anywhere along the flange/block area.

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    Willem "Wim" Blees, RPT
    Mililani, HI 96789
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    Original Message


  • 11.  RE:Pinblock to Plateflange Mating

    Posted 03-13-2014 21:57
    Wesley
    It is very important for the pin-block to fit the plate flange. If it doesn't fit tight against the plate then it can rock causing unstable pitch.


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    Thomas Black
    Decatur AL
    256-350-9315
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    Original Message


  • 12.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-13-2014 21:59
    Depends on the piano.  Some blocks don't contact the flange at all.  Typically these are ones with tuning pin bushings or tuning pin to plate contact.  However, a fitted block is a good idea generally and necessary on many pianos.  Glassing the block is the easiest way to get a precise and continuous fit if you are installing it.  If the block is already in the piano then gluing thin wedges in along between the flange and the block is an easy way to secure things if you think it's contributing to an instability.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 13.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-15-2014 08:52


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    Daniel Berg
    Orlando FL
    407-884-1814
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    How about some comments on the 1/4" gap from the factory. These pianos have tuning pin bushings. No thought of mating at all. Is this wise engineering? That is a lot of tension for 2 dozen screws and pin bushings to stabilize!




    Original Message


  • 14.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-15-2014 09:49
    I used to work for a dealer until he closed his doors, and installed a lot of player systems.  If the keybed would come off, I did it like that.  You would probably be amazed at the number of pianos being manufactured that you can pass a business card or more between the pinblock and plate flange, all the way from one end to the other, or most of it. With the keybed off and the piano on it's side, the space in question is right before your eyes.  When putting in a new block, I can't help but think that a solid mating is better, no matter what the manufacturer's take on it is. The question is, what is solid?  I like to glass them to get a good fit, but most of it comes with a belt sander and a spoke shave.  What do some of you others use?

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    Clark A. Sprague, RPT
    Bowling Green, OH
    www.clarkspianoservice.com
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    Original Message


  • 15.  RE: Pinblock to Plateflange Mating

    Posted 03-15-2014 09:19
    On 3/15/2014 7:52 AM, Daniel Berg via Piano Technicians Guild wrote:
    > ------------------------------------------- Daniel Berg Orlando FL
    > 407-884-1814 -------------------------------------------
    >
    > How about some comments on the 1/4" gap from the factory. These
    > pianos have tuning pin bushings. No thought of mating at all. Is this
    > wise engineering? That is a lot of tension for 2 dozen screws and pin
    > bushings to stabilize!

    Yet it works quite well. In my experience the pianos intentionally built
    this way are no more unstable than another piano intentionally built
    with a full fit to the plate flange. Just because we see something
    different from what we were taught, doesn't automatically mean it's
    wrong or deficient. If it works as intended and works well, the
    deficiency is in our understanding, rather than in the engineering.
    Ron N


    Original Message


  • 16.  RE: Pinblock to Plateflange Mating

    Posted 03-15-2014 10:25
    On 3/15/2014 8:48 AM, Clark Sprague via Piano Technicians Guild wrote:

    > The question is, what is solid? I
    > like to glass them to get a good fit, but most of it comes with a
    > belt sander and a spoke shave. What do some of you others use?

    I've seen little if anything I could reasonably conclude was tuning
    instability caused by the usual gaps found in so many pianos. I used to
    track this years ago, but haven't bothered for a long time. It just
    seems to be a non problem in all but very rare instances.

    Fitting new blocks, I disc sand and check, getting as good a mechanical
    fit as I can without wasting all day on it, then glass it on final plate
    installation for 100% support. I don't believe it helps long term tuning
    stability one whit, but I think it provides a solid foundation earlier
    on when the tension goes on and everything crushes and settles to fit. I
    don't top fit, and never saw any benefit to it other than to clear major
    plate casting goobers if any are present.
    Ron N


    Original Message


  • 17.  RE:Pinblock to Plateflange Mating

    Registered Piano Technician
    Posted 03-16-2014 10:33


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    Daniel Berg
    Orlando FL
    407-884-1814
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    35K lbs tension (strung piano).......about 24 screws with sheer strength of about 24K lbs sitting against cast iron with incredible compression strength should put us at or above 35K for holding strength. The screws alone could hold 8 Toyota Camry's. We don't need the flange at all by this calculation if somewhat accurate. If you were holding the bottom of the pin you would be pulled forward and up so there is strength added from the webbing as well unless it's an open tuning system. Open tuning system with no screws in the pinblock field we need strength from a flange or similar barrier at the front and some stability for keeping pinblock from going up such as a perimeter flange over the top of the pinblock. So.....

    If we are stable.....why is there discussion about tuning instability with poor mating of pinblock to flange. Are there other factors that cause the instability.

    e.g. I tune a large grand. The capo section would not stay in tune, then began breaking wire often. I restrung the capo section. The piano is not played hard and I have taken several suggested measures to reduce power to the strings. Capo wire continues to be unstable and wire breaks regularly. Breaks are always at the capo. The pinblock is NOT tight to the flange in the capo section.

    My conclusion after 7 years of this is that the wire is moving for some reason and the capo is wearing the wire to breakage or the tension of scale is causing a problem. Hammers?....I doubt it. Not played hard either....I have that with other pianos.

    Give me your wisdom 

    Photos attached of original question subject of new piano




    Original Message


  • 18.  RE: Pinblock to Plateflange Mating

    Posted 03-16-2014 10:59
    On 3/16/2014 9:33 AM, Daniel Berg via Piano Technicians Guild wrote:
    > ------------------------------------------- Daniel Berg Orlando FL
    > 407-884-1814 -------------------------------------------
    >
    > 35K lbs tension (strung piano).......about 24 screws with sheer
    > strength of about 24K lbs sitting against cast iron with incredible
    > compression strength should put us at or above 35K for holding
    > strength. The screws alone could hold 8 Toyota Camry's. We don't need
    > the flange at all by this calculation if somewhat accurate. If you
    > were holding the bottom of the pin you would be pulled forward and up
    > so there is strength added from the webbing as well unless it's an
    > open tuning system. Open tuning system with no screws in the pinblock
    > field we need strength from a flange or similar barrier at the front
    > and some stability for keeping pinblock from going up such as a
    > perimeter flange over the top of the pinblock. So.....
    >
    > If we are stable.....why is there discussion about tuning instability
    > with poor mating of pinblock to flange. Are there other factors that
    > cause the instability.
    >
    > e.g. I tune a large grand. The capo section would not stay in tune,
    > then began breaking wire often. I restrung the capo section. The
    > piano is not played hard and I have taken several suggested measures
    > to reduce power to the strings. Capo wire continues to be unstable
    > and wire breaks regularly. Breaks are always at the capo. The
    > pinblock is NOT tight to the flange in the capo section.
    >
    > My conclusion after 7 years of this is that the wire is moving for
    > some reason and the capo is wearing the wire to breakage or the
    > tension of scale is causing a problem. Hammers?....I doubt it. Not
    > played hard either....I have that with other pianos.
    >
    > Give me your wisdom

    Better yet, generate some wisdom of your own. You can speculate about
    this for the rest of your life and not know, or you can epoxy and hammer
    in some wedges between the plate flange and the block and see if that
    cures the tuning and string breakage problems. Then you'll know.
    Ron N


    Original Message