Music Trade Review

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41
The Music Trade Review
MAY 8, 1926
The Technical and Supply Department—(Continued from page 40)
Leslie Hoskins, of the Miessner Piano
Co., Talks on Wrest-Plank Construction
Superintendent of Milwaukee Piano Manufacturing Firm Speaks Before the Monthly Meeting of
the Western Division of the National Technicians' Association—Second Article
ALTER HAUSCHILD then submitted
W his
criticism, an abstract of which follows:
"By using a spring scale and placing it two
inches from end of tuning hammer placed on
a pin in the wrest plank, it was found that a
sixteen-pound pull gave a normal clinch on
the pin, at which normal tuning can be accom-
plished. This pull measured fourteen pounds
when the scale was placed at the extreme end
of the tuning hammer. I should hesitate to
send out pianos with less than twelve pounds
or more than eighteen or twenty pounds.
"The above test was made in a plank that
bored out perfectly, the drill leaving a clean
white hole. As to keeping the tuning pin at a
proper clinch over a period of years I am
strongly of the opinion that the type of con-
struction has much to do with this.
"We know that even varnish is not im-
pervious to moisture, but it is the safest material
we can apply to-day that is practicable. A bush-
ing plank will undoubtedly increase in moisture
content much more rapidly than an open plank
varnished and the necessary end grain of a
bushing will take on moisture more rapidly than
side surface. Because of this I firmly believe
that the open plank varnished will retain a nor-
mal condition much longer than a bushing
plank, the bushings being unfinished. We be-
lieve in an exposed pin plank covered by an
otherwise full plate because the pin can be
driven deeper and at an angle, although this
necessitates a somewhat heavier plate.
"Accepting the theory of 6 per cent moisture
as correct and giving the lumber plenty of
time in the conditioning room before and after
gluing, we should select quarter-sawed maple as
the best material for wrest planks because it
has the firmest texture, will not split or crack,
nor shrink or expand quite as much as other
cuts. The cost is higher and this may be the
cause for the more general use of plain-sawn
maple. Northern Michigan rock maple plain
sawn is classed next.
"The number of the joints in a wrest plank
is immaterial, in my opinion, and only the best
grade of animal glue should be used for the
joints. After the. pin plank is glued to the back
the tuning-pin holes should be bored with a
somewhat smaller bit or drill at not too high a
speed and be left standing for at least three or
four weeks to give the air a chance to get into
the holes in the planks.
"Next, the stringer before driving the pins
reams the holes with a reamer which has the
exact size for tuning pins. In this way any
variation in the size of the hole caused by
shrinkage or expansion will be corrected.
"The point I bring up here is, that after hav-
ing determined the approximate moisture con-
tent that the core stock and ply should be before
applying the glue, it is essential (and I am in-
clined to believe, more essential) that the mois-
ture content at the time of boring should ap-
proximate what might be termed a normal con-
dition to-day. This, for the reason that a moist
or too moist plank will char when bored, but
a dry plank will not char. The charred plank
will cause the most trouble. The dry plank
that cuts a smooth white hole will cause the
least, as regards excessive swelling, greater
receptivity to moisture (because the dry,
smooth hole hugs the pin closer) and conse-
quently greater swelling and contracting; for
the swelling can do but one thing: that is, ulti-
mately result in a bruised wood about the pin,
and absence of resistency in the fiber of the
wood under construction.
"We find that when our planks are placed
between sticks for thirty or sixty days after
being glued up our boring trouble is nil. The
result is a clean, white hole and a normal, per-
manent clinch.
"I prefer plain sawed for the pin plank core
and also for ply rather than quartered or
rotary cut. However, the three-sixteenth-inch
rotary cut is proving a satisfactory ply and I
doubt if appreciable difference could be de-
tected in the cross-cut as there is only three-
eighths of an inch resting against the tuning
pin. But because of the necessity of breaking
the fiber on one side of the rotary cut I agree
with Mr. Hoskins that the lengthwise plain
sawed ply is superior to the rotary cut."
Eugene Flint, a glue specialist, was called on
for a few words of comment and spoke as fol-
lows:
"I am going to ask you to study these two
tubes that I have with me. These two tests
are a comparison of bone and hide glue. Both
these tubes were handled under the same con-
ditions. The glue was mixed with twice its
weight of water, both tubes put in an incubator
for seventy-two hours at a temperature of 100
degrees Fahrenheit. If these impurities were
brought out in this space of time with only 100
degrees of heat, just speculate a bit on how
much more foreign matter can be brought to
light in your glue pots with your average pre-
vailing temperature of about 140 to ISO degrees.
Heat is and always will be one of the telltales
of glue; heat in this case has brought out just
what is in glue. This cannot help but be the
case in your glue pot.
"It has been proven that glue holds the joint
together and not the water used in making the
solution. Good glue should not take more than
approximately twice its physical weight in
water. It is impossible to tell you exactly how
to use your glue, your own immediate condi-
tions decide this matter. I always advise mak-
ing two or three experimental batches, making
comparative tests on these to arrive at the best
mixture for your individual conditions.
"A glue film between two surfaces represents
the joint, depending on how well made the glue
is and how uniform the surfaces are. This bone
glue makes an adhesive that penetrates evenly
over the whole surface to a uniform depth. A
thick bodied glue that has had a lot of water
added to it is naturally applied in a thicker
solution and remains a thick jelly-like mass be-
tween the surfaces until the water has been
absorbed or driven out through clamping. After
the surplus water is out you have nothing left
but a thick, uneven, very porous mass of glue,
which, after drying and setting, leaves a very
poorly made joint, due, no doubt, to the many
spots of no contact between glue and surfaces.
Thick-bodied glues in setting and drying coagu-
late to an alarming degree, which only means
that they cannot hold in an efficient manner,
nor for the same length of time as the glue
before you."
to the absence of President-elect Charles Miller,
no action of appointing a program committee
was possible, but it was thought wise to hear
suggestions by members in order to place the
general feeling of the club on record, to be
acted upon later as the administration sees fit.
Some of the most pertinent suggestions were
made by retiring president E. Voelckel, who
proposed that some technical subject be assigned
one or more of the superintendents at each
meeting. Mr. Voelckel's idea carries with it
the belief that each member is an expert in
some branch of piano building and that the
reading of a prepared paper on the subject
would be mutually beneficial without revealing
the trade secrets of the superintendent's em-
ployer. Another plan of Mr. Voelckel was to
invite certain prominent local piano merchants
in order to get the retailer's angle of the good
and bad points of modern piano construction.
William Hausler, a past president of the club,
suggested that factory travelers could likewise
offer "pointers" to the superintendents by re-
counting various experiences in their contacts
with the retail trade throughout the country.
A. K. Gutsohn opened another avenue of
thought when he proposed a series of joint meet-
ings between foremen and superintendents for
the purpose of stimulating the younger gen-
eration to enter the piano business.
Another suggestion was made to invite supply
men to the meetings to discuss features of piano
building, on the basis of their particular special-
ization. Not the least of the enthusiastic pro-
posals for instilling greater interest in meetings
was that reported by E. M. Reulbach, secre-
tary of the club. He stated that the manu-
facturers were taking steps to arrange a joint
meeting between manufacturers and superin-
tendents in the near future and that every means
would be taken to effect closer co-operation
between these two branches.
Remember Us
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The American Piano Supply Co.,
New Plans to Widen Scope
of Superintendents' Club
New York Piano Manufacturers' Association
Promises Financial Support and Greater Co-
operation for Its Work
The general rejuvenation of the Superin-
tendents' Club of the New York Piano Manu-
facturers' Association at its annual meeting
recently, which is traceable to the financial sup-
port and interest just extended by the manu-
facturers, has resulted in some splendid plans
for programs during the coming year. Owing
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UKULELE ATTACHMENT
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160 So. Park St.
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