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Bosendorfer and Steinway hammer reshaping profile

  • 1.  Bosendorfer and Steinway hammer reshaping profile

    Posted 10-13-2024 15:15

    With embarrassment recently having done a warts-and-all video preparing an instrument for a concert within two hours I watched myself reshaping the hammers of a Steinway removing the shoulders of the grooves and thinking that perhaps I wasn't rounding them enough. It was with delight that someone gave a link to the Steinway maintenance manual showing the hammers to be shaped more diamond than olive-like.

    Today I a Model L Steinway faced me demanding reshaping and likewise as well also as a Bosendorfer 225. This instrument is situated in a cavern of a church and the sound was strangely lost. The tone was hard and from the back the sound was only a tinkle. Lack of resonance in tuning is one matter but the hammers were entirely flat and horrible. Whether or not it will be possible to redeem them remains to be seen.

    In refacing the Bosendorfer hammers should I be aiming for the olive or the diamond profile?

    Best wishes

    David P



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    David Pinnegar BSc ARCS
    Hammerwood Park, East Grinstead, Sussex, UK
    +44 1342 850594
    "High Definition" Tuning
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  • 2.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-13-2024 18:44

    David,

    I have long sought to follow the profile of the hammer (i.e., rounded) on the Bosendorfer whereas I go for the diamond shape on the Steinway. 

    Peter Grey Piano Doctor 



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    Peter Grey
    Stratham NH
    (603) 686-2395
    pianodoctor57@gmail.com
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  • 3.  RE: Bosendorfer and Steinway hammer reshaping profile

    Posted 10-13-2024 19:32
    Dear Peter

    Thanks so much and very helpful indeed and vital as first step guide.

    The Bosendorfer is lacking in solid power and the flat surface is near half an inch - so possibly a good 1/8th of an inch of top felt must have been worn away. I haven't had the action out but commented to the owner that really new hammers might be the only answer.

    Some time ago I read Orbeck's book on voicing and changing the shape must have a substantial influence on tone, and potentially power. One might think that to get any sort of near the same diameter of roundness will involve taking off potentially rather more felt and lower the mass.

    Beyond our own practices and anecdotal thoughts, have there been any studies on the tonal differences of the hammer geometry? We want to minimise that contact point with the string whilst enabling it to squash and compress to a wider contact on more powerful blows. The diamond would make compression easier one might suppose whereas the more rounded will give the contact point more support. The way it behaves will depend also upon the type of felt chosen for both types of hammers. 

    It's really nice to be able to know what one's doing but also why one's doing it in such a way rather than another.

    Best wishes

    David P

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    David Pinnegar, B.Sc., A.R.C.S.
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    +44 1342 850594



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  • 4.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-14-2024 04:52

    Speaking of Bosendorfer, I was just invited to spend 2 weeks at the Bosendorfer factory for their concert prep protocol. The shaping of their hammers, I'm sure, will be a big focus during my time there.

    But to echo what several have said, I tend to follow the general outline of a more aggressive shoulder to get the diamond shape.

    Tom Servinsky 

    Registered Piano Technician

    Concert Artist Piano Technician

    Conductor Emeritus-Treasure Coast Youth Symphony

    Conductor Emertius- Academy Orchestra

    Jazz Pianist for events

    tompiano@tomservinsky.com

    772 221 1011 office

    772 260 7110 cell

     




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  • 5.  RE: Bosendorfer and Steinway hammer reshaping profile

    Posted 10-14-2024 08:23
    Thanks so much - really helpful and much appreciated. An egg is a lovely description of the shape.

    https://youtu.be/bGBRdLT3LRg?t=163 was my approach on the Steinway. Perhaps there might be things that are possible which might be better. That occasion was a terrible hurry, unexpected work just 2 hours before a concert so I might well have been more rough and ready. I didn't show it in the video but thanks to Susan Kline's method of "liquid steam" with the vodka trick the felts toned down beautifully and https://youtu.be/Wiu68b85N1Y?t=159 was the result that evening.

    Upon consideration the lack of power of the Bosendorfer might indicate doping to be the answer with paraloid and if so I'm referring the instrument to a UK colleague for an estimate.

    On reshaping to a curve with a one hammer wide strip of sandpaper as I documented on https://youtu.be/prWp46UGerQ?t=114 I find it very difficult to pull the strip straight and level. It's easy for the sandpaper to slip off the side. On that instrument I wasn't too worried as it was a wreck rescue job but a concert Bosendorfer is a different kettle of fish. Perhaps people might have knacks to achieve better perfection?

    Best wishes and many thanks

    David P

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    David Pinnegar, B.Sc., A.R.C.S.
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    +44 1342 850594



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  • 6.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-14-2024 09:37

    The way I understand Stwy's diamond-shape hammer profile is this:

    1.) Stwy has long been one to start with a soft hammer and reinforce this felt with resins (first shellac, now plastics)

    2.) Their application of resins has a foundation of some uniform level of reinforcing running shoulder-to-shoulder and through the crown

    3.) If you cut into the shoulders to create this profile (replacing a the hammer press caul's curve with a straight line), you have effectively removed the crown's anchoring to the shoulders. With this constraining anchoring removed, the crown takes on some flexibility which is independent of the needling (spreading of fibers) that we might think called for, because of the initial uniform wash of resin. IOW, this flexibility can be induced without crown needling.

    JMHO…



  • 7.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-13-2024 20:20

    For the Bosendorfer the egg profile is preferred.  Sounds like new hammers may be needed.



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    Parker Leigh RPT
    Winchester VA
    (540) 722-3865
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  • 8.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-14-2024 08:25

    I spent 3 months at the Bosendorfer factory in 1980.  Spent about a month on hammer shaping and voicing.   They are very picky

    about hammer/string fit.



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


  • 9.  RE: Bosendorfer and Steinway hammer reshaping profile

    Posted 10-15-2024 07:59

    David-

    Here are drawings from one of the voicing room walls taken when I worked there in 2007. I learned a great deal about shaping during my time there.

    David



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    David C. Brown RPT
    Garland TX
    tunermandb88.com
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    Original Message


  • 10.  RE: Bosendorfer and Steinway hammer reshaping profile

    Posted 10-15-2024 08:27
    David -  thanks so much

    Unfortunately the link goes to
    "Library Entry was not found. The document you've requested is no longer available. It may have been moved or deleted. Please contact the administrator for more information."

    Email address is antespam@gmail.com and it would be really appreciated - thanks so much

    With regard to Steinway hammers there is a difference between New York and Hamburg. NY hammers are soft and have to be hardened up. Hamburg hammers are hard and have to be softened up. This has an influence on reshaping and as pointed out, taking the shoulders off flattening of NY hammers will remove some of the relevant doping whereas removing shoulders on Hamburg hammers is fine.

    This is of particular relevance as the Steinway M with flat hammers is a New York instrument. Someone kindly put a video on YouTube about chemical voicing and it looks as though hairspray will have to be in my tool-kit, doping where the shoulders will have been removed. Thanks so much for reminding me about this. The instrument is interesting as it has a label on the soundboard trumpeting that it's a Diaphrammatic soundboard. (Others more expert might have more perspective on this but for anyone who hasn't heard of it the idea is for it to have a thinner more flexible rim so that the whole centre of the soundboard has a pistonic action rather than a model effect with travelling and standing waves. This may have relevance to sound projection one might think . . . )

    Best wishes

    David P

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    David Pinnegar, B.Sc., A.R.C.S.
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    +44 1342 850594



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  • 11.  RE: Bosendorfer and Steinway hammer reshaping profile

    Registered Piano Technician
    Posted 10-16-2024 07:49
    Hi, David.

    How good to see you here. 

    If you posted the link, it did not attach. I'd like to view it for comparison to what I received
    from Peter. 

    Thanks,

    Dave







    --
    Dave Conte, RPT, CCT
    Owner, Rocky Top Piano
    Knoxville, TN
    817-307-5656





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  • 12.  RE: Bosendorfer and Steinway hammer reshaping profile

    Posted 10-16-2024 07:59
    Thanks David. Glad to be able to contribute.



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    David C. Brown RPT
    Garland TX
    tunermandb88.com
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    Original Message