Music Trade Review

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THE MUSIC TRADE REVIEW
13
TRADE TECHNICIANS DISCUSS CHARACTERISTICS OF WOOD—(Continued from page 12)
Mr. Dewey: "It would be pretty hard to re-
place that wood."
A Substitute for Maple
Mr. Arnold: "One thing we must not forget
in looking for a substitute for maple pin blocks.
If we use wood that is too hard and the fibre
too fine, the hardness is of a crystalline nature
and the pin wouldn't hold. Even in maple if
we pick a piece with a swirly knot and get two
of them together the pin would be loose in a
short time because the threads of the pin are so
fine they block readily. We find the qualities
that grip the pin in a pin block is found in the
end wood. The qualities that hold the pin rigid
is found in the long wood. The long wood
part in the pin block will hold the threads of
the screw when turned whereas the pull on the
pin rests on the end wood, and that becomes
very rigid. If we should take a piece of pin
block material and laminate it our tuning pin
would not hold. The wrest plank must be of
the same kind of wood, hard maple, and especial-
ly so if a thinner pin block is used so that the
pin itself has a bearing in the wrest plank. I
am speaking of uprights."
Dr. Laufer: "Maple is fatty, due to the fact
that it is made up entirely of very close hard
knitted wood fibre cells with practically no ducts
in it. When your pin enters between those
cells, they form levers on that screw. If you
get a wood made up of stone fibre cells, such
as some of the nut woods, say butternut, you
find the condition you spoke about."
Mr. Bartlett: "Isn't it very likely that the
peculiar cell formation of the maple is perhaps
one of its most valuable qualities for pin block
construction?"
Dr. Laufer: "Undoubtedly. It has practical-
ly no ducts in it. Because of its stringy rope-
like wood fibre cells, it clings tenaciously to the
pin."
Mr. Johanson: "The question has often come
up between piano manufacturers whether the
quarter sawed wrest plank or the plain sawed
would be the best. What maple would hold
best?"
Dr. Laufer: "A plain sawed maple."
Mr. Johanson: "Can you give us any sugges-
tions regarding our core wood? The Eastern
manufacturers are using more white pine than
we ar-e. We are using more chestnut and pop-
lar."
Mr. Barth: "You can get more white pine for
veneering purposes than chestnut or poplar."
Mr. Johanson: "In using white pine for sides
of a piano, one objection is its softness. We
are using perfectly clear poplar. Willow would
warp more than poplar."
Dr. Laufer: "The yellow poplar and bass wood
that you have been getting is largely willow."
Mr. Johanson: "In that case all of our piano
manufacturers are being deceived!"
Dr. Laufer: "The difference is just botan-
ical. The grain and color of the two woods
are so closely alike that the layman cannot tell
.the two apart, consequently it doesn't make
much difference whether you call them by one
name or another."
Mr. Johanson: "A very important point in
the construction of a piano case for perma-
nency is found in the core wood. There are
certain parts of a piano case where pine can-
not be used. The foot block would not be
hard enough to hold the screws for the casters.
The foot rail, on account of its cut in the cen-
ter, would not be strong enough. We could
not use it for fall boards because of the finishing
of the ends and moldings. You could hardly
use it for sides unless lined with poplar or some
harder wood. Pine is apt to be dead and dozey
to a certain extent, and it is apt to shrink in."
Mr. Arnold: "If we use a narrow board from
a small tree or a wide board from a large tree,
we find the wide board has less tendency to
warp. Why does the narrow board warp more
readily?"
Sap Layers in Small Trees
Dr. Laufer: "A small tree possesses a pro-
portionally larger sap layer. A board six inches
wide from a seven-inch tree will have a greater
proportion of sap wood than an eighteen-inch
board from a twenty-two-inch tree. The sap
wood is capable of taking up more moisture
than the heart wood and this larger proportion
of sap wood produces a greater tendency to
twist and warp in the narrow board. The sap
wood takes moisture readily even after curing
the heart wood very much less readily. A wide
board, sawed, glued and veneered, under ordi-
nary conditions will last a hundred years. A
narrow board, in about ten years, may cause
trouble because the sap wood takes up moisture,
causes the glue to swell and produces checking
and sweating in the veneer."
Mr. Barth: "Kiln drying of lumber is like bak-
ing a loaf of bread. It dries it on the outside
and swells it on the inside. Kiln drying leaves
the wood on the inside soft like the inner part
of the loaf and the outside dry and hard like
the crust of the loaf. It is a problem that the
lumberman has been unable to solve."
Dr. Laufer: "From a tonal standpoint, if we
seasoned our woods just as the old violin makers
did we would approach perfection."
Mr. Barth: "Some pattern makers purchase
their lumber three or four years before using
and pile it under cover where it is absolutely
dry and well aired. The pattern lumber they
use today is four or five years old and absolute-
ly dry. I can only say, buy your lumber far
enough ahead and put it into a dry place."
The Value of Seasoned Wood
Dr. Laufer: "The manufacturer should not
use lumber unless he has had it for five years.
Piling on ends under a shed would increase
warping. No matter how careful you are there
would be more moisture on one end of the board
than at the other and hence the greater danger
of warping. It would be best to pile it in
the flat well cleated so as to secure perfect
drying. The manufacturer has lost sight of the
fact that lumber is not just wood. It is not a
question of 'what is wood?' It is a question of
'why is wood?' and that has been pointed out
to be due to histological factors. Whenever
you take a board and put it in a dry kiln and
turn on a roasting temperature you have ruined
that wood tonally, because you have developed
inside the cells of the component fiber an in-
ternal stress, the same as exists in an iron
plate or any manufactured product that is sub-
mitted to a wrong heat treatment. Wood is
not living matter, but you have internal mois-
ture—water with a mineral content. This min-
eral content will be variable. It will consist
of salts, lime in connection with phosphorus, sul-
phur and nitrogen—all salts that are extremely
soluble. In placing the wood in a dry kiln
you dry the outer portion of the cells. You
rapidly heat the lumen or the inside of the
cell, causing the cell walls to be fractured and
disintegrated. It matters not if a certain pro-
portion of the cells contain either air or water^
when heated artificially. You get the condition
Mr. Barth pointed out. This tears every fiber
of that wood apart, due to the internal stress
you develop and ruins it for tonal purposes."
Mr. Dewey: "Perhaps some of you have
found that oak honeycombs through rapid dry-
ing."
The Effect of Rapid Drying
Dr. Laufer: "You can try that on any board.
Take a board, put it through the planer and
sander, look over it carefully and you will find
a beautiful, unbroken surface. Put it through
the dry kiln and you will find little checks run-
ning all the way through it. When that occurs
the internal stress makes puffed rice out of it."
Mr. Barth: "We sell kiln-dried lumber only
on the basis of its grading before it is kiln-
dried. It is possible to reduce the grading by
kiln-drying."
Mr. Johanson: "I believe you all appreciate
the way we handle lumber is to have it in stacks
from two to five years. If the manufacturer
should maintain a five years' supply of all woods,
some manufacturers would have millions of feet.
That is quite an item when it comes to money.
I believe most of us are keeping the lumber
up to four years. When it comes to core stock
it would hardly pay."
Dr. Laufer: "Don't you give it a short dry-
kiln treatment before using?"
Mr. Johanson: "We do. Would you air dry
it down to the finish?"
Mr. Barth: "When you kiln dry it readily
reabsorbs dampness because the pores are all
open and the dampness goes in in spite of any-
thing you can do to prevent it."
Mr. Johanson: "In air drying lumber, sup-
pose it does not go through your dry kiln,
what percentage of moisture would it hold?"
Dr. Laufer: "That is difficult to tell. I would
recommend that the lumber be taken and air
dried five years and then brought in to the
mill room from one end and passed through a
room in which a current of live air is circu-
lating. In a week your lumber would be fairly
dry. Vitalized air on lumber that has seasoned
is very powerful. You bring your lumber from
the yard and it goes itto the ait-drying room
and is moved slowly to the point of usage. By
that time it has lost all the surface moisture
it had accumulated and you have dry lumber
which will not pick up much moisture."
Mr. Dewey: "The remaining moisture con-
tent would largely be in the heart of the piece
and would not give one-hundredth part as much
trouble as the moisture that would be taken
on the surface of the piece."
Mr. Johanson: "Should it be dried in the
open air?"
Dr. Laufer: "I would dry it in the open with
a roof over it. I would pile the valuable lumber
in the center, the next most valuable lumber
on the sides and the cheapest lumber on the
outside. In this way the maple is getting all
tlie air but is not depreciating because the mois-
ture and elements do not get at it."
It was announced that the subject for the
next meeting would be piano actions. There
will be actions from various makers and repre-
sentatives from various companies to present
their claims. The meeting will be held Febru-
ary 21. 1917, at 208 South La Salle street.
AMERICAN BRASS FORGING CO., INC.
Manufacturers of
PIANO AND PLAYER-PIANO HARDWARE
SUCCESSORS TO THE
168-172 Southern Boulevard
N e w York Piano Hardware Co.
New York City