Pianotech

  • 1.  What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Member
    Posted 12-12-2023 17:40

    Working on a 1922 Steinway O right now.  The action stack is a bit low according to Steinway specifications.

    Taking measurements at the five action brackets, the hammer shank pin centers are 144.7 to 145.0 mm from the action bed. Steinway spec is 146 mm, so they are 1 to 1.3 mm too low. 

    The wippen pin centers are from 80.1 to 80.7 mm from the action bed. Steinway spec is 82.6, so they are .9 to 2 mm too low.

    String height in bass section varies from 198 to 199.3mm. In tenor section string height is 191 to 191.5 mm, and in treble section string height is 191.0 mm on key #61 tapering down to 189.1 mm on key #88.

    Some of the experienced technicians I have been talking to say to shim and raise the action so that the distance from the key bed to the shank and wippen pin centers is on spec. Then do a custom hammer bore to compensate for varying string heights.

    But, on some older discussion threads, some say that Steinway may have set the top action stack deliberately lower to compensate for a lower than spec string height. Because of that I want to get some fresh opinions about this question.

    What do you all think about this question? And how do you proceed with setting shank and wippen center pin height when you have a piano with lower than spec string heights.

    Thanks for your help!



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    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
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  • 2.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-13-2023 07:47

    Joe,

    Double check your bass string height measurements. Something is seriously off there. Your treble string height is pretty close to typical SS spec of 7.5"

    Also,  what would be your hammer bore spec as is?

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 3.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Member
    Posted 12-13-2023 10:00

    Oh, I made a mistake in typing the bass string heights. I have corrected it.  I am going to put new hammers on the piano, so I can do custom hammer bore if needed.



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    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
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    Original Message


  • 4.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-13-2023 15:18

    Joseph, 

    In my experience, custom boring hammers always makes more refined regulation possible. This is likely due to the fact that every piano on which I have measured string height based on multiple samples has had some net string rise or fall within each section.

    Boring all the treble hammers at one distance, and all the bass hammers at another saves time, but does not yield the most accurate result.

    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


  • 5.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-13-2023 08:08
    No piano is the same. All have various degrees of imperfections. Short of redesigning a piano and changing the dimensions of all aspects, our jobs as piano technicians is to work with what we have and make adjustments to make everything work. 

    Wim





  • 6.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Member
    Posted 12-13-2023 10:02

    Hi Wim,

    I am aware of what you are saying. Do you have any advice on how to proceed with this piano?

    Thanks Joe



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    Joe Burros
    Cell: 646-410-7174
    jbcello@gmail.com
    www.fmi-newengland.com
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    Original Message


  • 7.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-13-2023 11:00
    You're boring your own hammers. That's a good start. 
    You're already keeping accurate measurements. Be prepared to make changes, but only if you know what will work and what won't, and understand why you're going to make those changes. 



    Original Message


  • 8.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-13-2023 15:05

    Hi Joseph,

    That's pretty darn close, so unless you have reason to move the stack up, I'd leave it. Just because S&S specs say so, well that's not a great reason to raise the stack. They often don't follow their own specs.

    Otherwise, if you want to find out if the stack really needs raising, I would check the magic line (half strike line) to see if it's correct. That parameter makes a significant friction difference. Having the stack a mm high or low might make no difference at all, except for affecting the hammer bore of course.

    We use a 12" thin flexible metal rule and fix it in place with blue painter's tape (bottom of key at pivot to wippen flange center). A 5 mm block under the white key front and a small weight gives you half strike. From the side, the ruler should intersect the capstan/wippen connection for lowest friction. 

    We check this parameter when building new keysets, especially if there's an external shoe. Sometimes we can modify the external shoe on the new keyset and improve the magic line, sometimes other changes are needed such as adjusting the stack height.

    Hope that helps,

    -Dean Reyburn, RPT



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    Dean Reyburn, RPT
    Reyburn Pianoworks
    Reyburn CyberTuner
    1-616-498-9854
    dean@reyburn.com
    www.reyburnpianoworks.com
    www.cybertuner.com
    www.reyburntools.com
    Facebook: www.facebook.com/dean.reyburn
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  • 9.  RE: What's more important? Correct shank & wippen center pin distance to key bed or distance to bottom of string?

    Registered Piano Technician
    Posted 12-14-2023 07:51

    The problem with trying to change the hammer center height to match the string heights is that the stack has a level of stiffness to it.  If you try to move the height down, the result might be that the action fram is pulled up instead.   This can result in knocking on the back rail of the piano.  The Steinway stack is not as rigid as other pianos, so you can cheat and flex it a little bit, but beware that every action as a reaction as well.  I would aim for a neutral tension between the action rail and the stack.



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    Tom Dowell
    Hulbert Piano
    tom@hulbertpiano.com
    262-221-0792
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