Pianotech

  • 1.  Liquid and other voicings and a shoutout to Susan Kline with thanks

    Posted 09-03-2022 15:11
    An instrument in Greece gave me a hard time recently. Thanks to all who advised on electronic additions to the action. That might be the subject of another thread in due course.

    The venue was an outside amphitheatre and the instrument was kept in ideal climate controlled conditions off-stage.


    The Yamaha C3 was 23 years old and the hammers grooved. In my experience as soon as grooves are visible on Yamaha hammers the sound gets harsh.
    This was a tough call. In an outside auditorium the instrument needed to retain power as well as being able to cut through an orchestra. The grooves were probably around 10mm
    and I decided to reshape the olive shape of the hammers - sorry - I should have taken side on photos of before and after and leave probably 50% of the groove lengths.

    Then I did something which may or may not have made a difference. With familiarity with Abel hammers, when the hammers are cut apart, the sides of the hammer felts are not held together as the centres, so wool fibre tensions are likely to be higher in the centre and more relaxed on the edges. I'd normally have steamed the hammers - but (and incidental to this post) a set of hammers that I steamed in Genoa and sounded lovely have gone hard again within a month in the high summer temperatures) that was not the answer here. I wanted to do something more controllably. Susan Kline's liquid voicing was the answer. I'd done it before but had difficulty controlling the drop. Here I wanted to be more subtle so I applied two microdrops of Vodka neat from the bottle upon the centre groove. The idea was just to make the centre of the hammer a little more malleable in correction of the compaction in the groove.

    For application, I found a Greek stalk of grass with a knuckle and upon that I broke the stem and used this to carry the liquid by surface tension. It was enough for two drops to be applied reliably.

    The result? I'll leave that to you to decide - 
    https://www.youtube.com/watch?v=M7QaEmtc-4o
    YouTube remove preview
    Uploaded by None on 2022-08-30.
    View this on YouTube >


    Of course I would fail PTG exams. 

    And my tuning most certainly. At this point  anyone can hear the piano and orchestra being _exactly_ in tune with each other, the piano note and cello being indistinguishable, the piano blending as part of the orchestra as an orchestral instrument rather than against it.

    The musicians were really delighted and afterwards

     

    THANKS to Susan for her inspiration and advice.

    Now I've got to return to Genoa to refurbish another Bechstein and revisit the hammers I steamed. Upon recalling discussion of Ballistol might this be the answer for a more permanent softening where steaming has been too temporary?

    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: Liquid and other voicings and a shoutout to Susan Kline with thanks

    Posted 09-03-2022 16:16

    Wow, I got shouted out!

    This whole thing has been great fun, especially when I heard how the piano sounded in the recording. Here I sit in my Oregon computer room, yet I've been only one step removed from being a piano technician in Greece! I think David took my advice and applied it in an excellent fashion, exactly suited to the requirements.




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  • 3.  RE: Liquid and other voicings and a shoutout to Susan Kline with thanks

    Posted 09-11-2022 17:50
    Last week I came to another instrument which not only sounded hard but had very visibly degraded hammers. I sanded but not completely removed the grooves https://www.youtube.com/watch?v=feW_mPE73ks and, to bring a swelling of felt in the middle of the hammer, applied one drop of Vodka to the centre groove. The video documents the result.

    Any thoughts on sanding technique would be appreciated. What I'm doing has achieved success but could it be better?

    When sanding with a strip of sandpaper I've found that if I use a strip only one hammer wide, it's easy to slip out of line and skew the draw across the felt.By using a paper 1 1/2 hammers wide, I might do only 1/2 of the adjacent hammer, which is then corrected on the next but this keeps the draw of the paper straight. Perhaps it would be better to do it with double width strips?

    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: Liquid and other voicings and a shoutout to Susan Kline with thanks

    Posted 09-11-2022 22:14

    Hi, David

    When filing treble grand hammers, I use a block about 5 inches wide (narrowly triangular in cross section) which slides down (narrow end down) in front of the back checks. It allows the hammer tails to be supported. Then I can use a wider hammer file or tape-backed piece of sandpaper, and all the hammers will be exactly the same height. I slide it along so that the new unfiled hammers are next to a couple of filed ones, encouraging them all to be filed in a similar fashion.

    Without the block, you appear to still be getting good results, but I do find the block helpful.

    For the tenor hammers and the bass hammers I still use the block, but lift each hammer in turn and file it with a thin wooden slat 2" wide which has 220 grit sandpaper glued to it. Because of the angles at which they are bored, each has to be individually filed, but having them all in a row helps me to get them all to have the same profile, and makes it easy to see if I am filing them square instead of crookedly (favoring the bass or treble side.)

    You seem to be happy with the results of shortening the grooves, restoring the oval shape of the hammer, but not taking the shortened grooves all the way off, and then using minimal vodka right at the top to put a little cushion in the sound.

    Well, it's what I like to do ... glad it's working for you.




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  • 5.  RE: Liquid and other voicings and a shoutout to Susan Kline with thanks

    Registered Piano Technician
    Posted 09-12-2022 08:24
    David, as Susan mentioned, a voicing block or two should greatly help your reshaping efforts - particularly in gang filing multiple hammers at a time. Pianoforte Supply has a nice set of voicing blocks that work quite well. You might also look into their Microfinish filing kit, which uses high quality aluminum oxide grit on a stiff yet flexible backing, and it comes in strips that are both 1 hammer wide and 3 hammers wide..

    I'm not sure of the common piano supply companies available in the UK/Europe, but they will surely have voicing blocks as well.

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    Adam Schulte-Bukowinski, RPT
    Piano Technician
    Glenn Korff School of Music
    University of Nebraska at Lincoln
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