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TECHNICAL^SUPPIY DEPARTMENT
William Braid^I\nte,TechnicalEditor
The Wrest Plank, Its Functions and
Its Design, in the Scale of the Piano
The Steinway practice has always been to bed
the wrest plank into the arms of the case and
then fit the iron plate over it, using the iron
rib before mentioned, and also another iron
lug which projects forward and is fastened into
Wrest Plank Not Exactly a Massive Piece of Construction tor the Load It Has to Carry, and the head block at the back of the key-bed. All
this extra care is for the purpose of securing
Cdftsequently It Presents to the Scale Designer a Problem of No Little Importance
a
rigid, immovable wrest plank. I need hardly
—Another Article in the Series on the Design and Planning of the Piano Scale
point out that the difficulty here is in the neces-
HE last previous article in the scale draw- of the waste wire between the agraffe and the sary separation of the wrest plank from the
ing series appeared on November 27, tuning pin should be as short as it can properly main framing of the case.
when I was speaking about drawing in the be made. In the upper treble the capo d'astro
Pin Lengths and Plank Thickness
hitch-pin holes and treating the waste ends of bar construction calls for a length of wire be-
While on this subject we shall do well to de-
the strings. It is now time to think about tween the bearing edge of the bar and the edge cide in advance what thickness of wrest plank
drawing in the tuning-pin holes.
of the tuning-pin section of the iron plate. This we desire. I like a long tuning pin, and pre-
Our string lines, which indicate the middle length, however, should not exceed one inch, fer the size known as 0000X2^, that is to say,
:string or line of each unison, will, of course, but on the other hand the distance between this two and one-half inches long by a diameter of
have been drawn right up to the forward edge edge and the nearest tuning pin in each unison 0.28" or 0.29". Such a pin should penetrate into
of the iron plate, or rather to where that should be sufficient to prevent a steep slope of the wood of the wrest plank to a depth of not
forward edge will come; so that there should the wire, which always puts on additional strain less than 1V6" and if the tuning-pin plate be, say,
be no trouble whatever in seeing where at least at the point where the coil on the pin begins.
5/16" thick, that means that the length of pin
one tuning-pin hole for each unison should go.
Of course it is true that as the strings be- above the plate will be approximately 13/16".
Before, however, we begin to lay out these come longer and longer the amount of space
The wrest plank then should be built accord-
holes, we must take thought for a moment con- available for the treatment of length between ingly and should also be just so thick that the
cerning the wrest plank, especially as to the agraffe and pin becomes constantly smaller. bottom ends of the pins need not be pushed
best way of spacing the pins through it. A Thus, the longest strings are the worst off in quite through it. It is always better to have
wrest plank is not exactly a very massive con- this respect. We must take all possible care, the bottoms of the pins covered, even if only by
struction, considering the load it has to carry. however, not to have the length too short be- a very thin sheath of the wood of the wrest
It is evident at first sight that there must be tween agraffe and tuning pin, and must be plank.
enough wood between each pair of adjacent guided by the steepness of the slope. A slope
From what has been said, it is plain that the
pins to enable these to resist the pull of the of 10 degrees is quite enough.
tuning-pin holes must be bored in the iron so
tuned strings. On the other hand, if the space
On the other hand, if and when we can divide as to accommodate pins 0.29" in diameter. It is
between each pair be too great the pull across the slope into two parts, as by the interposition usual to have the holes, in fact, y 2 " in diameter
the face of the plank will be excessive.
of a pressure bar between agraffe and pin, the as finally bored. When drawing in the holes,
Other things being equal, we may start off angles may be greatly reduced in steepness, however, it will be sufficient to draw them of
with the general understanding that the length with consequent better tuning and much less the actual diameter of the pins, and then ap-
forward pull on the wrest plank.
pend a note to the drawing directing that these
In dealing with all these matters it is neces- holes be drilled to fit pins of size shown.
sary to keep in mind the great point that the
The question of bushing pins comes in here
wrest plank has to resist the forward stress and helps to determine the matter of diameter
imposed by all the two hundred and twenty-five of holes as bored in the iron plate. I think for
or more wires, which stress is constantly oper- myself that wooden bushings are unnecessary,
ating to move the plank towards the belly and that they do not add anything at all to the
bridge. That is why, of course, grand wrest stability or other valuable qualities of the
planks are always fitted with an iron rib struction. They certainly do not help the pin
against which the plank may abut. Even when to sustain the strain upon it. At most they
thus supported, however, the grand wrest plank reduce slightly the unsupported length of the
is never perfectly rigid. Every tuner, I sup- pin, but they are not easily fitted closely enough
pose, knows that a well-made upright piano will to do even this effectively.
stand in tune better than a grand of equally
Our large stock ii rery leldom
It should be remembered too that the pins
depleted, and your order, whether
good construction, mainly because of this mat- are to be fitted into the wrest plank with a
Urge or ttnali, will receire imme-
diate attention.
In addition, you
ter of wrest plank construction. I personally
get the very best of
prefer to cast two iron ribs under the plate in
Felts— Cloths— Hammers —
such a way that the wrest plank is completely
Punchings — Music Wire —
boxed in. This, I think, makes for rigidity, of
Tuning Pins—Player Parts-
which, as I said before, the construction of the
Associate, American Society of Mechanical
Hinges, etc.
grand piano does not allow more than enough
Engineers; Chairman, Wood Industries
in this region.
We have In stock a full line of
Division, A. S. M. E.; Member, American
material* for Piano* and Organ*.
Physical Society; Member, National Piano
Technicians' Association.
The American Piano Supply Co.,
T
Remember Us
William Braid White
WHY SACRIFICE
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T
HOUSANDS of dollars annually
are lost to dealers because of dam-
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reduced selling price. Tt is easy now for
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you how. This will be sent to you free
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The M. L. Campbell Co.
loos W. 8th St.
Punchings
Washers
Bridle Straps
5814-37th Ave.
Kansas City, Mo.
George W. Braunsdovf, Inc.
Direct Manufacturers of
TUNERS' TRADE SOLICITED
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 South State Street, CHICAGO
Piano
Also—Felts and
Cloths, Furnished
in Any Quantity
Woodside, L. I., N. Y.
28
Consulting Engineer to
the Piano Industry
Tuners and Technicians
are in demand. The trade needs tuners, regu-
lators and repairmen. Practical Shop School.
Si'iul for Catalan M
Y. M. C. A. Piano Technicians School
52nd and Sansom Sts.
Philadelphia, Pa.