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An Analysis of a Broken Plate
By Jim Ellis, RPT
Knoxville, TN Chapter
Background
When Steve Brady called and asked me if I would
contribute an article about broken piano plates
(to replace an article promised by someone else,
but which had never actually materialized), his deadline was
just five days away and I was leaving on a trip in three days.
When I returned it would be too late. Because of the time
constraint Steve and I decided that I should just use an
analysis that I did back in May, 1994 for the Journal article.
The piano was a 1973 J&C Fischer that had been
neglected for several years and allowed to go 37 cents flat.
The scale design had only three major divisions, no agraffes,
and the forward termination for the strings was a long
curved capo bar that ran all the way from #1 in the bass to
#88 in the treble. The middle section spanned 32 triplestring
unisons without any additional support and the
bearing angle of the strings against the bar was excessive.
The dimensional cross section of the bar was minimal, and
there were no shoulder (nose) bolts to secure the plate struts
to any beams underneath. Immediately after the tunertechnician
brought the piano up to standard pitch and
began to check the tuning, the middle section of the capo
bar broke.
Another technician claimed that the plate broke
because the tuner brought the piano back up to standard
pitch in one tuning rather than in several small increments
spread out over a period of days, weeks or months. The
owner filed a lawsuit against the tuner for an amount that, in
my opinion, was far in excess of the actual worth of the
piano. I was asked to be an “expert witness” for the tuner.
Although the piano was located in the Cincinnati area some
260 miles from where I live, I agreed to do it for net
expenses only. The intentions of the piano owner may have
been perfectly honest, but his/her decision to sue was based
upon an erroneous conclusion by another technician and
the result could have set a precedent that would have been
absolutely wrong!
After taking a good look at this particular piano I was
28 Piano Technicians Journal / November 2000
surprised that that section of the capo bar had not broken
when the piano was first chipped at the factory. I was later
told that some of them did.
The following is the analysis that I presented to the
tuner-technician’s attorney and I was well aware that I
might be called upon to present it in court later on. Fortunately
for everyone the suit was withdrawn the day before
the hearing. This was such a no-winner! The design of the
piano was, in my opinion, just asking for trouble.
The original analysis included four figures, which are
included here, and eight photographs — primarily for the
education of the attorney — that do not appear here
because they are no longer available.
Tuning Procedure Used by Mrs. Squire
Mrs. Squire and I discussed the procedure she had used to
tune the piano just before the plate broke. The piano had
been neglected and not tuned for more than a decade. Mrs.
Squire measured its pitch and found it to be about 37 cents
flat. In tonal nomenclature, a “cent” is 1/100 part of a
semitone; a “semitone” is 1/12 part of an octave; and an
octave represents a ratio of 2:1 in frequency, or pitch. In
going up the musical scale, each of the 12 semitones in an
octave increases by the 12th root of 2, or 1.059463094
above the one below it. Therefore, being “37 cents flat”
means that the frequency (pitch) of the notes on the piano
was about 98 percent of what it should have been at standard
pitch (A=440Hz).
When a piano is flat (low in pitch) by this much,
current procedure calls for raising the pitch of each string
very, very slightly above its normal frequency so that when
it settles after tuning it will be at, or very near, the desired
pitch. It is well within the limits of good tuning practice to
raise the pitch of a piano by 37 cents at one time. Obviously,
the tuner then repeats the tuning in order to obtain a finer
tuning, since the piano will always settle back some. This
procedure is accepted and recommended throughout the