Music Trade Review

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THE MUSIC TRADE REVIEW
11
Trade Technicians Discuss Piano Hammers and Felts
Some Interesting Information Concerning This Important Subject Offered By Vincent
Vilim Before Conference of Piano Men in Chicago—Keyboard Committee Makes Report
CHICAGO, III., December 11.—A regular con-
ference of piano technicians was held on Thurs-
day evening in the laboratory of the American
Steel & Wire Co., with F. E. Morton presiding
as chairman.
The Committee on Height of Keyboard ap-
pointed in October to report on the question:
"Shall the architecture govern the height of
grand keyboard or shall the height of keyboard
govern the height of architecture?" submitted
the following report, which is put in the form
of a recommendation:
"The convenience of the artist should be the
first consideration and a study of the height of
keyboards of several pianos frequently heard in
concert and recital leads to the inference that
whether through accident or design, similar di-
mensions are used in many of the well-known
pianos.
"It appears that the height of the white keys
is, in most of the cases considered, twenty-eight
inches. Some slight variation from twenty-
eight inches may be accounted for by different
methods in measuring or lack of care in taking
measurements, or even slight variations between
individual instruments, so that any manufac-
turer adopting twenty-eight ipches as standard
height for white keys in grand pianos cannot
be far wrong. The horizontal distance between
a perpendicular line dropped from the front end
of the white keys to the front end of the pedals
will naturally vary somewhat because of the
varying length of keys in grand pianos of differ-
ent sizes. A maximum distance of ten inches in
concert grands is probably about right; in small
sizes seven and one-half inches is more usual."
After the committee's report had been re-
ceived Mr. Morton said: "In our collaboration
and collective research, we have taken up the
manufacture of felt. The point at which we are
aiming must be kept in view, and that is to
place the responsibility for conditions. It is
fair to say that with the interest shown here,
the responsibility will be placed with or without
the assistance of those involved, from the sheep
to the finished hammer. This involves the ham-
mer maker and those who put it in the piano
and fit it for use. We may go further than that
and invite such persons as may determine what
happens to the hammer after leaving the fac-
tory, the tuner and repairman. To-night we
consider the man who receives the felt from
the felter and fabricates it for your use. In
looking for a man with a wide experience to
present this side to us, it seemed right and in
keeping with the purpose that we ask one using
all makes of felt—domestic and imported. He
should be able to define his position and re-
sponsibilities much better than one who only
used one make of felt. I found the Import
Felt Co., of New York, used the felts of a num-
ber of makers. In domestic felt they use Stand-
ard, Felters, American and Crane; in imported,
Weickert and Dittersdorfers' felt, and through
their interest in your welfare, which is identical
with their own, Vincent Vilim, president and
general manager of that, company, is here to
answer such questions as we may see fit to ask."
Vincent Vilim: "I a'ppreciate the opportunity
to be here to-night at the invitation of Mr. Mor-
toq. I have been making piano hammers for
twenty-six years. I like the business and want
to continue for the next fifty—if that is possible.
I have used all makes of felts and I find that
they differ greatly in quality. I have all kinds
of tapers here—the American, Straight and Ger-
man; also all kinds of felts and hammers fin-
ished and unfinished, down to the hammer molds.
We want to find out where your trouble lies.
I came here for your interest as well as mine,
and for that purpose I have everything here to
show you. First we take the hammer moldings
and count off as much as we need in the sets.
We then tighten them up in clamps. Then we
glue on the under felt (illustrates). It is then
usually pick it without trying it and some are
ovcrpicked. I find in many cases hammers
picked to death."
Mr. White: "In reference to top and under
felt, as the felt has to be stretched and ten-
sioned, is not the amount of stretching so far
in advance of all the other tensions that the
extra thickness would be negligible in prac-
tice?"
Mr. Vilim: "When we get a piece of felt with
a hard base or full taper we construct special
molds to get the right tension on all hammers.
We are carrying twelve special molds to meet
customers' requirements."
C. H. Jackson: "You will notice that on all
of these samples of hammers that one side of
the felt has not been properly glued on to the
front of the moldings. While this may seem a
trivial matter at first thought, 1 can say that
upon investigation I
have found this to be
the cause of weak
spots in the treble,
times without num-
ber. I have never
had to remove any of
the hammers in the
lower sections for this
reason, because it
would not be notice-
able unless they were
much looser than the
samples here. How-
ever, I have found
that where there is
the least bit of de-
fective glueing in the
treble hammers, that
it causes 'punk' or
'mushy' tones. 1 first
made this discovery
about five years ago,
and I have checked it
up very closely ever
since, and know what
I am talking about.
A Corner of the Laboratory Where the Conferences Are Held
single coat hammers would save labor and diffi- The hammers are from three different makers,
culty in glueing. In a discussion on glue he so you can see that the trouble is not confined
stated that a cold room required a high grade to any one hammer shop. I am not making
glue, but that his company kept its workroom the claim that this is the cause of all weak
trebles, but, however, when a weak spot shows
at eighty-five degrees all year around.
E. B. Bartlett: "Suppose you wanted to make up in a part of the treble, that is ordinarily
a set of hammers of that same size without the good, invariably it will be found that the ham-
under felt, you would naturally use a thicker mers are causing the trouble. At times I have
piece of felt. When you come to strain it over removed as many as eight and ten hammers
the molding, wouldn't you put a much greater that were in the same condition as these sam-
stress on the face of the hammer because of the ples,, and upon putting in new hammers, the
additional thickness of the felt, and wouldn't trouble was righted."
it be apt to tear apart more and be less dur-
Mr. Vilim: "One man glues one side and one
able than a thinner top felt?"
the other. The glue is applied to the felt only,
C. Arthur Brown: "That is true, but a change never to the molding. The trouble was ex-
in method might effect a difference in the perienced because the man who glued on one
side did not apply the glue all the way up to the
stress."
Wm. B. White suggested that three layers of under felt.
"We begin at the treble and press down by
felt would be better than one and Mr. Brown
replied: "If you were to carry that to an ab- hand toward the bass, and when we get the
surdity an infinitesimal number of layers of felt bass down to a certain depth, we work back
would give you an absolutely non-resilient ham- toward the treble. After it is down in the mold
we put our iron side cauls on and screw them
mer."
Mr. Bartlett: "In the old days they used to up. If a hard treble is required it is screwed
cap hammers with leather in order to give a hard. The workman regulates the tone of the
brightness. When you are down half the thick- hammer by the degree of pressure. He judges
ness of this top felt you are about through any- this by human touch—experience."
Mr. Morton: "Assuming that felt could be
way, and it is immaterial whether it strikes a
joint or not, it seems to me. There might be an so made and delivered to you with its resilience
objection to a second glue joint because of its and elastic limit known throughout the sheet,
effect on the elasticity. This underfelt is so would a machine or apparatus to measure your
far from the striking point it would be neg- tension on the side cauls be valuable? Would
it replace the human equation?"
ligible."
Mr. Vilim: "Yes, it would."
Mr. Morton: "Do you recognize an elastic
Mr. Brown: "Assuming that the felt is not
limit in felt?"
Mr. Vilim: "I do. There is a limit to every- uniform but possessed of variable elastic limit
thing. The tone regulator can spoil a good and resiliency, would a machine which would
hammer. I believe a good many tone regula- take cognizance of these conditions and bring
(Continued on page 13)
tors ought first to try their hammers. They
forced down into a small mold. It remains
in the mold for an hour and then is finished
up. When it comes out of the under felt mold,
it looks the same as a top felt and is tapered
the same. It is then ready for top felt glueing.
Here is a piece of straight taper felt. Only
a few manufacturers run the under felt all the
way through."
In response to a number of questions Mr.
Vilim stated that the underfelt was used largely
for appearance and served to build up the
hammer and that an inferior grade of under
felt had little bearing on the hammer, that it
was possible to make a twelve pound hammer
out of a thirteen pound felt by forcing into the
mold and giving just enough glue to hold. Jit
stated that hammers of under felt were made
largely to satisfy piano manufacturers and at a
cost of 30 cents more per set. He stated that