Private post/Steinway Tone Bell

[Delwin D Fandrich]

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  ----- Original Message -----=20
  From: Erwinspiano@aol.com=20
  To: pianotech@ptg.org=20
  Sent: October 17, 2003 9:13 PM
  Subject: Re: Private post/Steinway Tone Bell



    The bell is just a plate stiffening device. A short beam from the =
belly rail to the case in the same area would allow for another nose =
bolt that could take the place of the bell. I cant say the bell has any =
effect in and of itself to influence tone but does stiffen the plate web =
where it attaches thereby influencing tone. There must be a modest down =
force of the bell bolt to do so which by the way will increase the =
downbearing a small amount (tone effect) These bolts also seem to come =
loose from time to time and cause a weird rattle.

Take the coupling bolt out of a D sometime and listen to what happens to =
sustain through that area.


   Does that help?--Dale

       This reference to the "bell" brings to mind a question I have =
long had. S&S piano plates are sometimes billed as cupola plates. Does =
this refer to the shape of the stress holes in the plate, or to =
Steinway's use of a shop cupola furnace to produce sufficient amounts of =
molten iron for the larger plate ?=20

     Glenn
     I don't know. Anybody else? I thought  that term was used in =
reference to the bass bridges on S&S  uprights or have I got it ALL =
wrong?
      Dale
It is a reference to the shape of the plate in cross-section. Among =
other meanings this is an architectural term meaning a "dome-shaped =
roof" or a "dome on the roof." The hitchpin panel and the outer bolt =
flange are in one plane and the section between "domes" up in the shape =
of a cupola. The idea was to stiffen the plate and help keep it from =
twisting. I suspect it was introduced as part of the transition from =
earlier flat-strung scaling (with its more-or-less parallel lines of =
stress) to overstrung scaling which introduced quite a lot of torsional, =
or twisting, stress. Considering some of the iron being poured at the =
time -- some with tensile strengths as low as 12,000 to 15,000 lbs/in2 =
-- it is understandable why they might have considered many ways to =
increase the stiffness of the plate..

Del
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