CAUT

  • 1.  shimming Steinway action brackets

    Registered Piano Technician
    Posted 01-23-2015 12:14
    This message has been cross posted to the following Discussions: Concert Level Regulation and Preparation and CAUT .
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    Hello all,
    Here at my school I'm regulating a Steinway B circa 2003. It's impossible to get the jacks to align w/ the knuckles, even approximately, w/o making the hammer blow over 2 inches or having the hammers rest on the rest felt. I'm considering raising the stack- I have about 1/16" or a bit more clearance before the drop screws and hammer flange screws hit the pinblock. Will even this little bit help? Am I missing something? I understand of course that all kinds of futzing will have to be done with other aspects of the regulation: my question is whether shimming the stack is a course of action that should be considered. 
    Also, why is this happening? Did Steinway not bore the hammers properly? Other arcane mis-alignments?
    Any help would be greatly appreciated.
    Thanks much.

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    Stephen Kabat
    Lyndhurst OH
    216-381-5662
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  • 2.  RE: shimming Steinway action brackets

    Posted 01-23-2015 13:04
    What is the spread, and height differential between shank center and whip center...for a start.  Measured in a couple of places
    ji

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 3.  RE: shimming Steinway action brackets

    Posted 01-23-2015 13:30
    Actually though I can't tell the specifics yet, I suspect its a work around to accomodate off the charts string height. What is the string height mid tenor.
      ji

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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 4.  RE: shimming Steinway action brackets

    Registered Piano Technician
    Posted 01-23-2015 15:57
    Off the charts string heights my suspicion too - I have a 2004 D in my shop that is overcentering by as much as 8 mm.  The string height and hammer center pin height will tell him what the bore should be and what it is.  And it does not sound like there is much room to shim the stack up, what with only 1/16" of clearance. 

    It sounds like a problem that a stock set of NY hammers is not going to solve.

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    William Truitt
    Bridgewater NH
    603-744-2277
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  • 5.  RE: shimming Steinway action brackets

    Posted 01-24-2015 07:11
    How are the jacks lining up with the knuckle now; are they at an angle where by moving them forward makes no difference? If that's the case, you would need to shim up the back brackets which will rotate them forward at a better angle. No more than a 16th of an inch should do the trick. You'll find that it will ease the touchweight too if that's an issue as well. Aside from the spread, you can also check hammer center and rep center heights. The specs for Steinway are HC- 53/4" RC- 31/4". You may find discrepancies there too. Good luck! ------------------------------------------- Andrew Saderman Forest Hills NY 718-263-6508 -------------------------------------------


  • 6.  RE: shimming Steinway action brackets

    Posted 01-24-2015 08:14
    Try a 112.75 mm action spread and a 6.4 mm difference in height between HCH and WCH. Do not assume that the top action is situated properly either. String heights that are way off from even being anywhere near close to spec is always a problem. I don't know why it is but B's seem to be notorious for bad action geometry.

    To increase the spread, you do not need to remove the wippens. Back the screws out, remove the end wips and one in the middle. Feed a strip of sandpaper across the top of the rail and slip it back between the rail and flange.

    I've glued the paper faces together to make a double-thickness for when that much is needed. I use a heavy J weight 320 grit paper from Klingspor (available in rolls). It's also good for replacing the paper on flat hammer rails. Their fine emory rolls are great for S&S hammer rails.

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    Regards,

    Jon Page


  • 7.  RE: shimming Steinway action brackets

    Registered Piano Technician
    Posted 01-26-2015 10:48
    Hello all,

    thanks for all your posts. After measuring:

    1.     the spread is narrow by about 1/32"
    2.     the hammer and rep centers are at spec (5 3/4" + 3 1/4")
    3.     the difference in ht between HFC and RFC is 64mm (I think Jon had a typo there)
    4.     string ht. is 7 20/32" at note 51, the unwound strings being all about that distance +/-  1/32"
    5.     the hammershanks are off the rail about 8-9mm or about 4/16" to 5/16"

    It seems I should
    1.     shim out the reps appropriately (thanks Vince and Jon)
    2.     bore new hammers  - ?
    3.     raise the back end of the stack  -  ?

    Any further comments?

     I appreciate all the help
    Steve
    -------------------------------------------
    Stephen Kabat
    Lyndhurst OH
    216-381-5662
    -------------------------------------------




  • 8.  RE: shimming Steinway action brackets

    Registered Piano Technician
    Posted 01-26-2015 11:19
    So string height is about 194 mm (7 20/32"). In general, it should be about 190 mm. Pianos from the 60s and back in time through at least the 20s (average of what I have recorded over the years) are fairly consistent in the 188 - 191 range, while 80s - 90s tend to be 192 - 195, as high as 197. Shank center height tends to be pretty consistent at 144 (143 - 145), throughout that history. The same hammer bore has seemingly been used throughout (my guesstimates based on measurements and likely hammer wear). If anyone has data that would either amplify or dispute this picture, I'd love to hear about it. My data is base on tens, not hundreds of pianos. 

    Steinway bore for plain strings is about 46 mm, which is 190 - 144, so I have assumed that is at least close to the design standard (i.e., string height of 190, shank center height 144, bore, 46). A string height varying more than 2 - 3 mm higher begins to cause problems. When it reaches 4 - 6 mm, it becomes impossible to work with successfully by fudging, at least in my experience. You can make it work, but not well. String height is hard to change, so the obvious is changing the bore. I guess some fudging with spread and stack height could yield some gain, but I doubt it will entirely solve the problem. 
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou






  • 9.  RE: shimming Steinway action brackets

    Posted 01-26-2015 11:30
    Then you throw in the 5mm string height difference between the mid tenor
    and high treble, and it gets to be even more fun.

    Ron N