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Steinway treble understring card

  • 1.  Steinway treble understring card

    Posted 04-20-2025 00:21
    Hi All,
    I am restringing my personal piano, a 1927 Steinway L. Although I have restrung several other pianos, I have not come across the "card" which is was glued to bottom of the treble understring felt. I've attached several photos. I am asking the group what material to use as a replacement for this card. It appears like it could be heavy card stock, but after nearly 100 years, I can't be sure. Suggestions?
    Thanks, 
    Denis Kelly
    San Anselmo, CA


  • 2.  RE: Steinway treble understring card
    Best Answer

    Registered Piano Technician
    Posted 04-21-2025 07:27

    Dennis,

    This material is referred to as vulcanized paper or vulcanized card stock. Steinway's Parts Department used to sell it to the trade by the sheet. I may still have a portion of a sheet. 

    David G. Hughes, RPT



    ------------------------------
    David Hughes RPT
    Vintage Case Parts
    Glyndon MD
    (443) 522-2201
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  • 3.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-21-2025 11:34
    Just a point of curiosity, is that the same stuff they use under the cheek blocks, that one thins or removes to adjust the downward pressure on the guide pins?






  • 4.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-21-2025 11:58

    Nathan,

    Yes.

    David G. Hughes, RPT



    ------------------------------
    David Hughes RPT
    Vintage Case Parts
    Glyndon MD
    (443) 522-2201
    ------------------------------



  • 5.  RE: Steinway treble understring card

    Posted 04-21-2025 16:48

    Thank you, David,
    I have sourced the understring material and it is on the way to me, but I appreciate your offer very much.

    Denis Kelly



    ------------------------------
    Denis Kelly
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  • 6.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-22-2025 07:53

    Denis, would you mind sharing where you sourced your stock?



    ------------------------------
    Dave Conte, RPT

    Piano Technician in Residence
    The University of Tennessee
    College of Music
    Knoxville TN
    (817) 307-5656
    Owner: Rocky Top Piano
    ------------------------------



  • 7.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-24-2025 10:02

    The Steinway Parts Department sells red vulcanized fiberboard in sheets of 25" x 40".  (Part number 007999)



    ------------------------------
    Daniel DeBiasio
    Technical Education & Support
    ddebiasio@steinway.com
    718-267-3229
    Steinway & Sons
    ------------------------------



  • 8.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-22-2025 19:00

    David Hughes is correct , red card stock.

    I remember it being called "fish paper" in NY.



    ------------------------------
    Gerry
    Gerald P. Cousins, RPT ~ Director of Piano Service and Resources
    West Chester University of PA
    gcousins@wcupa.edu
    ------------------------------



  • 9.  RE: Steinway treble understring card

    Posted 04-23-2025 02:27

    I never liked the card stock as underlayment for the strings. Mainly because the angle has to go up to the tuning pin whick leaves an ugly coil to the trained eye. I make mine out of Hickory or Ash and carve it on the sander with the intent of having the strings travel parallel to the plate. It looks so good too.

    -chris



    ------------------------------
    Chernobieff Piano Restorations

    Inertia Touch Wave(ITW) The most advanced silky smooth actions.

    Engineered Hygroscopic Soundboards. The strongest and lightest boards made today for acoustic projection, richness and warmth.

    865-986-7720 (text only please)
    ------------------------------



  • 10.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-23-2025 06:26





  • 11.  RE: Steinway treble understring card

    Registered Piano Technician
    Posted 04-24-2025 03:06

    I have been using fishpaper for  many years as repair material for split keys (spinet keys that break at the balance rail pin).  The material is very tough and makes a great reinforcement material, better than thin veneer.

    The only problem with it is that some versions will not take glue well, so you may need to try different  suppliers.



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    Blaine Hebert RPT
    Duarte CA
    (626) 390-0512
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