Music Trade Review

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TECHNICAL^SUPPIY DEPARTMENT
William Braid White, Technical Editor
The Run of the String to the Tuning
Pins and Their Holes in the Plate
The Width of Each Trichord at the Point of Contact With the Hammer—The Wrest Plank and
the Piano Plate—The Intent Being Plain There Should Be No Difficulty in Drawing These
Lines—The Problem of Loose Ends—"Harmonic Stringing" and the Duplex Scale
Y this time we have our drawing looking
something like the scale of a piano. The
strings are set in, from bearings to
bridges, and the hitch pin points are located.
We may now draw in lines showing the run of
the strings to the tuning pins and locate the
center of the holes which must be bored in the
plate in order to accommodate the tuning pins.
Beginning with the trichord unisons in the
treble we note that the distance from center
string to center string of adjacent trichords is
one-half inch. We shall at once see that if we
are to avoid a disorderly and dangerous rubbing
of the wires against each other as they leave
the bearings (agraffe or capo d'astro) on their
way to the tuning pins, we must draw the three
wires of each trichord spaced so that they
occupy a width of about one-quarter of an inch
where the hammer strikes them, that is to say,
from outside edge of the first wire in the tri-
chord to the outside edge of the third wire.
Now if we try to draw in the tuning-pin holes
with enough space from one to the other to
afford fair clearance for the wires, we shall find
that we have to space them well over the wrest
plank. On the other hand (and here is a point
not always remembered), if we spread the pins
widely over the wrest plank, we set up two
counter-stresses, each of which is undesirable.
The first arises from the considerable differ-
ences which will come to exist among the
lengths of the wires between bearing and pins
in each trichord. The second is due to the
transvere stress across the face of the wrest
planks which will be produced by locating every
third pin so far towards the front of the plank.
It is not always realized that the grand piano
is structurally weak, in a way not known to
the upright, by reason of the gap which has to
be left for the movements of the hammers.
Because of this gap, the wrest plank is cut off
from the back of the piano and from the brac-
ings which form part of that back, and must
therefore obtain all its power to resist the
stresses imposed by the tuned strings, from its
fastenings under the iron plate. This point
must not be overlooked, and it is indeed so im-
portant that I shall speak of it here at some
length.
••
Wrest Plank and Plate
more closely and be less inclined to give under
the influence of the strings.
When the strings are being drawn in between
agraffes and pins in the bichord bass section,
the line already drawn at each unison is taken,
of course, to represent the center line (im-
aginary) between the two wires of the bichord.
There should be no difficulty in drawing these
lines, for the intent everywhere is plain
enough.
Waste Ends
Before drawing in, however, the tuning pin
holes, it is advisable to consider somewhat the
question of distance from pin to agraffe or bar.
At the capo-d'astro bar section we have to re-
member that there has to be a length of wire
between the center of the bearing edge of the
bar to the plate bearing behind the bar, where
the wires come up over an iron or brass surface
and travel to the tuning pin. This length
should not be more than one inch for the
short strings, but may be taken as about one-
half of the length of the wire at C 6 (No. 76)
and as about one-fourth of the length at C 5
(No. 62). In the scale under discussion the
capo-d'astro bar will run down to unison No.
58. On account of this length of open wire for
each string, which by the way is sometimes
dignified with the name duplex scale, but which
is seldom accurately enough designed to de-
serve it, the tuning pins must be placed not too
far behind the plate bearing. A distance of two
and one-half inches is plenty.
Where the agraffes begin, however, we find
that the lengths of the strings increase so
rapidly and the line of agraffes come so near
towards the extreme outside edge of the plate
that as the scale proceeds downwards to the
bass the length of wire between agraffe and
tuning pin constantly diminishes. This need
not give us any concern so long as we are care-
ful to avoid too steep slopes from the level at
which the string leaves the agraffe and that at
which it reaches the pin. The difference in
level is required in order that there may be a
sufficient strain upon the wires where they are
bent, on crossfng from one level to another, to
assure that they shall not rattle between
agraffe and tuning pin. Of course it is advis-
" Examination of the underside of a grand
piano plate will show that the position of the
wrest plank is, as it were, marked out by a
long and heavy flange against which the front
edge (nearest to the hammers) of the plank ;
caused to rest when it is fastened by screws to
the plate above it. The object of the flange, of
course, is to secure the plank from pulling for-
ward, which otherwise would almost certainly
occur. As a matter of fact it would be still bet-
ter to carry this same flange all the way around
so as completely to box in the wrest plank,
which then undoubtedly could be fitted much
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43
able to damp the waste ends of the wires, ex-
cept when these are deliberately left open in
order to afford the duplex scale effect. The
damping can be effected by means of tape
woven in or a felt pad under the wires.
"Harmonic Stringing"
A word should here be said on this ques-
tion of the duplex scale, so called. This was
first made famous by the late C. F. Theodore
Steinway, who introduced it, I think, in his
famous B grand scale. It consists, in practice,
of leaving between capo-d'astro bar and plate
bearing a length erf open wire, carefully deter-
mined in order to set off a definite fraction of
the speaking length of the string. This open
length then may be expected to vibrate when
the hammer strikes the speaking part of the
string, and since its length is one-half, one-
third, or one-fourth of the speaking length it
may be expected to emit the corresponding
partial tone, thereby strengthening or enrich-
ing the sound complex. To what extent this
actually takes place is always very hard to say.
Personally I do not think that the effect is very
great. All the experiments I have made (and
they have been many) convince me that there
is some, but not a great, effect.
Some eminent makers have given much time
to trying to do something with those waste
ends of the wire which lie between the belly
bridges and the hitch pins. For many years
the house of Bluthner in Germany has built
its pianos on what it calls the Aliquot scale,
which means that the waste ends aforesaid are
spaced off in definite fractions of the speaking
lengths and bearings are placed accordingly,
so that each string has a portion of its waste
lengths vibrating in some partial tone to its
fundamental. But again it is doubtful how
much additional partial toue complexity one
actually obtains in these circumstances. Thai
the strings do vibrate in these waste lengths is
certain enough. The only really important
question is whether the effects of the vibrations
are sufficiently powerful.
After a good many attempts at doing some-
thing original with waste ends, I have come to
the conclusion that Theodore Steinway said
both the first and the last word on this particu-
lar subject, and that it is not possible in a
{Continued on page 44)
William Braid White
Associate, American Society of Mechanical
Engineers; Chairman, Wood Industries
Division, A. S. M. E.; Member, American
Physical Society; Member, National Piano
Technicians' Association.
Consulting Engineer to
the Piano Industry
Tonally and Mechanically Correct Scales
Tonal and Technical Surveys of Product
Tonal Betterment Work in Factories
References
to manufacturers of unquestioned
position in industry
For particulars, address
209 Sou* State Street, CHICAGO
Piano Technicians School
Courses in Piano Tuning, Regulating and Repairing.
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Professional Tuners have taken our courses to
broaden the scope of their work. Write for Catalog R.
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