Music Trade Review
Issue: 1927 Vol. 84 N. 22 - Page 101
Music Trade Review -- © mbsi.org, arcade-museum.com -- digitized with support from namm.org
TECHNICALANDSUPPIY
DEPARTMENT
William Braid White, Technical Editor
"Taking Bearing"—What It Means, Its
Purpose and the Way of Its Process
Object of "Down Bearing" Is to Impart a Rigidity to the Fastenings of the Strings—
Where the Tuner Can Aid the Manufacturer
D
URING the process of bellying, by which
is meant the adjustment of the sound
board to the scale of the piano in the
course of assembly, many interesting and some-
what mysterious-appearing works are executed,
which to the casual visitor remain puzzling if
not entirely unintelligible. I am reminded of
'this after a recent attempt to explain verbally
the process known as "taking bearing," to an
intelligent technician whose interests lie in other
departments of piano construction.
Meaning of "Crown"
The sound board of a piano is arched or
"crowned" during the process of ribbing, bridg-
ing, etc. This arching or crowning is under-
taken for the purpose of putting the texture
of the built-up spruce-wood structure into a
state of compression, especially along a line
roughly co-directional with the line of the long
bridge. In order, however, that the strings cross-
ing over the long and the short bridges shall
be rigidly supported and be able to vibrate
under the most powerful blows which can be
inflicted on them by the hammers, it has been
found necessary to give to them what is called
a "down-bearing." This means that from a
fixed point of reference each string shall be
somewhat higher in level at the bridge than
it is at either the hitch-pin or the tuning-pin
bearing.
Object of Down Bearing
Now, it must be insisted that the only object
of "down bearing" in itself is to impart a rig-
idity to the fastenings of the strings. If each
string were to run level from bearing to bridge,
then obviously the longer strings would tend
to rattle slightly at the point where each rests
against the nearer of the two staggered pins
between which it travels over the bridge. At
least under powerful blows, such a tendency
would be almost inevitable. Therefore it is
found advisable to cause the string to bend up-
wards slightly as it reaches the first pin, and
slightly downwards as it leaves the second one.
Moreover, at the bearing on the iron plate near
the tuning pins, the string as it starts towards
the sound board bridge will by the same means
also be bent slightly upwards. Bendings at
these points of contact are the immediate re-
sults of "down bearing."
Methods of Obtaining "Down Bearing"
Now how is this down bearing obtained?
When the crowned sound board has been glued
onto the inside rim of the case on a grand
piano (the process is parallel on an upright),
the iron plate must next be fitted, to assure
that the string lengths shall be correctly laid.
When the plate has thus been fitted it will
probably be found in almost every case that
the upper surface of each sound board bridge
requires to be planed down more or less. The
process known as "taking bearing" concerns it-
self with this latter point.
It may readily be seen that, after the plate
has been fitted and screwed down into place,
Punching!
Washers
Bridle Straps
5814-37th
so that the lengths of the longest and shortest
strings in both the overstrung and tinderstrung
divisions of the scale have been correctly as-
sured, the process of taking bearing is compar-
atively easy. A simple method is to place over
the plate at each of several selected points a
steel bar resting upon the plate at points be-
tween the tuning-pin bearing and the front rib
on one side, and on the other upon the hitch-
pin plate. If now this bar be shaped so that
where it crosses the sound board bridge part
of its lower edge may be allowed to straddle
the bridge, while showing a definite point in-
dicated for the correct level of the upper sur-
face of the bridge with reference to the bear-
ing bar of the plate, this point may be marked
or, by a slight change in the arrangements, a
saw may be put in place to cut a kerf in the
wood of the bridge until caused to stop at a
depth equivalent to the required level at that
point. If this process is repeated at several
selected points, with the exact relative height
of the bridge previously determined and in-
dicated •in any suitable way, the bellyman can
then plane down the top surface of the bridge
to the indicated level. The statement applies
of course to both the long and the short bridges.
All sorts of different ways of indicating the
proper level of the upper surface of the bridge
are used in, different factories, most of them
being intended to enable the bellyman to get
his levels automatically. I mentioned the method
of cutting a kerf in the wood with a small saw
until- the latter is stopped when its upper edge
grounds against a plate put there for the pur-
pose. Another way is to drill holes in the steel
bar through which a drill may be put, which in
turn is used to drill holes into the wood until
brought to a stop in a similar predetermined
manner.
Bearing Frame
Of course, it will at once be seen that this
or any similar arrangement is best carried out
by means of a rather elaborate frame, carrying
at least four crossing bars for the long bridge
and two for the short one, with the levels
worked out at each point and arrangements
made to allow for cutting or otherwise indi-
cating the required level at each point selected.
If one were thinking only of accuracy, of
Magic Scratch Remover
Campbell's Mag-ic Scratch Remover in-
stantly eradicates scratches and scars
from wood finishes. Highly valuable—
in fact, indispensable, wherever furniture
or musical instruments are handled. Used
by any employee. Quick, effective—and
very economical.
The cost of Magic Scratch Remover is
very small, indeed. Housewives gladly
pay a good price.
'
I '•• "'
Your price, y 2 doz., $2.00; doz.,
$3.50. Postpaid. Sent on approval.
THE M. L. CAMPBELL COMPANY
1008 West Eighth Street
George W. BraunsdorS, Inc.
Direct Manufacturers of
TUNERS' TRADE SOLICITED
Kansas City, Mo.
William Braid White
Associate, American Society of Mechanical
Engineers; Chairman, Wood Industries
Division, A. S. M. E.; Member, American
Physical Society; Member, National Piano
Technicians' Association.
Consulting Engineer to
the Piano Industry
Tonally and Mechanically Cerraet Scalea
Teaal and Technical Snireya ef Product
Tonal Betterment Work la Facterie*
KtftrncH
te manufacturers ef unquestioned
petition lm industry
for
partieulmr$,
209 South State Street, CHICAGO
Piano Tuners
Also—Felts and
Cloths, Furnished
In Any Quantity
Woodside, L. I., N. Y.
99
course, by far the simplest and best method of
"taking bearing" would be to stretch a piece of
string (not a steel wire piano string) across
from bearing bar or agraffe to sound board
bridge, at each point measure the relative
heights of the string above the surface of the
board and mark the bridge accordingly for
cutting.
Wholesale methods of "taking bearing" will
always be more or less inaccurate owing to
variations in the dimensions of the cast-iron
plates.
And lastly it may be pointed out that the
wooden bridges are always made higher than
they will ultimately become, in order to allow
for such variations in plate and case dimen-
sions.
"Bearing" in General
Now, having dealt with this important matter,
we may go on to consider the whole question
of "bearing" as related to sound board, bridges,
bearing bars, agraffes, tuning pins, hitch pins
etc.
Very little study has been given to the
subject, although it deserves the most careful
investigation, for it is extremely important in
its effect upon tone, stability of tuning, etc.
In the first place let me say with complete
assurance that the only object of providing
these differences in string levels which con-
stitute what we call "down" or "side" bearing
is the establishment of rigidity. The string
stretched at high tension receivea blows which
may be delivered with all the power of the
pianists arm enforced through his finger tips,
and so is in great need of rigid fastening. Yet
along with this the string must be arranged
so that, the tuner can increase or decrease its
tension at will without disturbing its power
to remain thus rigidly fastened. Hence the
otherwise rather unintelligible arrangements of
agraffes, staggered pins on sound board bridges,
capo d'astro bars, pressure bars, and so on.
"Bearing" in its various mechanical phases is
a matter of rigidity and of nothing else.
As such of course it is important, nay, es-
sential, although in the particular case which
I began by describing, the necessary bendings
of the wire could easily be made by mechanical;
arrangements on the sound board bridge, with-
out requiring the latter to be otherwise fitted.
(Continued on page 101)
and
Technicians
are in demand. The trade needa tuner*, reru-
latora and repairmen. Practical Shop School.
Send for Catalog hf
Y. M. C. A. Piano Technicians School
1421 Arch St.
Philadelphia, Pa
TECHNICALANDSUPPIY
DEPARTMENT
William Braid White, Technical Editor
"Taking Bearing"—What It Means, Its
Purpose and the Way of Its Process
Object of "Down Bearing" Is to Impart a Rigidity to the Fastenings of the Strings—
Where the Tuner Can Aid the Manufacturer
D
URING the process of bellying, by which
is meant the adjustment of the sound
board to the scale of the piano in the
course of assembly, many interesting and some-
what mysterious-appearing works are executed,
which to the casual visitor remain puzzling if
not entirely unintelligible. I am reminded of
'this after a recent attempt to explain verbally
the process known as "taking bearing," to an
intelligent technician whose interests lie in other
departments of piano construction.
Meaning of "Crown"
The sound board of a piano is arched or
"crowned" during the process of ribbing, bridg-
ing, etc. This arching or crowning is under-
taken for the purpose of putting the texture
of the built-up spruce-wood structure into a
state of compression, especially along a line
roughly co-directional with the line of the long
bridge. In order, however, that the strings cross-
ing over the long and the short bridges shall
be rigidly supported and be able to vibrate
under the most powerful blows which can be
inflicted on them by the hammers, it has been
found necessary to give to them what is called
a "down-bearing." This means that from a
fixed point of reference each string shall be
somewhat higher in level at the bridge than
it is at either the hitch-pin or the tuning-pin
bearing.
Object of Down Bearing
Now, it must be insisted that the only object
of "down bearing" in itself is to impart a rig-
idity to the fastenings of the strings. If each
string were to run level from bearing to bridge,
then obviously the longer strings would tend
to rattle slightly at the point where each rests
against the nearer of the two staggered pins
between which it travels over the bridge. At
least under powerful blows, such a tendency
would be almost inevitable. Therefore it is
found advisable to cause the string to bend up-
wards slightly as it reaches the first pin, and
slightly downwards as it leaves the second one.
Moreover, at the bearing on the iron plate near
the tuning pins, the string as it starts towards
the sound board bridge will by the same means
also be bent slightly upwards. Bendings at
these points of contact are the immediate re-
sults of "down bearing."
Methods of Obtaining "Down Bearing"
Now how is this down bearing obtained?
When the crowned sound board has been glued
onto the inside rim of the case on a grand
piano (the process is parallel on an upright),
the iron plate must next be fitted, to assure
that the string lengths shall be correctly laid.
When the plate has thus been fitted it will
probably be found in almost every case that
the upper surface of each sound board bridge
requires to be planed down more or less. The
process known as "taking bearing" concerns it-
self with this latter point.
It may readily be seen that, after the plate
has been fitted and screwed down into place,
Punching!
Washers
Bridle Straps
5814-37th
so that the lengths of the longest and shortest
strings in both the overstrung and tinderstrung
divisions of the scale have been correctly as-
sured, the process of taking bearing is compar-
atively easy. A simple method is to place over
the plate at each of several selected points a
steel bar resting upon the plate at points be-
tween the tuning-pin bearing and the front rib
on one side, and on the other upon the hitch-
pin plate. If now this bar be shaped so that
where it crosses the sound board bridge part
of its lower edge may be allowed to straddle
the bridge, while showing a definite point in-
dicated for the correct level of the upper sur-
face of the bridge with reference to the bear-
ing bar of the plate, this point may be marked
or, by a slight change in the arrangements, a
saw may be put in place to cut a kerf in the
wood of the bridge until caused to stop at a
depth equivalent to the required level at that
point. If this process is repeated at several
selected points, with the exact relative height
of the bridge previously determined and in-
dicated •in any suitable way, the bellyman can
then plane down the top surface of the bridge
to the indicated level. The statement applies
of course to both the long and the short bridges.
All sorts of different ways of indicating the
proper level of the upper surface of the bridge
are used in, different factories, most of them
being intended to enable the bellyman to get
his levels automatically. I mentioned the method
of cutting a kerf in the wood with a small saw
until- the latter is stopped when its upper edge
grounds against a plate put there for the pur-
pose. Another way is to drill holes in the steel
bar through which a drill may be put, which in
turn is used to drill holes into the wood until
brought to a stop in a similar predetermined
manner.
Bearing Frame
Of course, it will at once be seen that this
or any similar arrangement is best carried out
by means of a rather elaborate frame, carrying
at least four crossing bars for the long bridge
and two for the short one, with the levels
worked out at each point and arrangements
made to allow for cutting or otherwise indi-
cating the required level at each point selected.
If one were thinking only of accuracy, of
Magic Scratch Remover
Campbell's Mag-ic Scratch Remover in-
stantly eradicates scratches and scars
from wood finishes. Highly valuable—
in fact, indispensable, wherever furniture
or musical instruments are handled. Used
by any employee. Quick, effective—and
very economical.
The cost of Magic Scratch Remover is
very small, indeed. Housewives gladly
pay a good price.
'
I '•• "'
Your price, y 2 doz., $2.00; doz.,
$3.50. Postpaid. Sent on approval.
THE M. L. CAMPBELL COMPANY
1008 West Eighth Street
George W. BraunsdorS, Inc.
Direct Manufacturers of
TUNERS' TRADE SOLICITED
Kansas City, Mo.
William Braid White
Associate, American Society of Mechanical
Engineers; Chairman, Wood Industries
Division, A. S. M. E.; Member, American
Physical Society; Member, National Piano
Technicians' Association.
Consulting Engineer to
the Piano Industry
Tonally and Mechanically Cerraet Scalea
Teaal and Technical Snireya ef Product
Tonal Betterment Work la Facterie*
KtftrncH
te manufacturers ef unquestioned
petition lm industry
for
partieulmr$,
209 South State Street, CHICAGO
Piano Tuners
Also—Felts and
Cloths, Furnished
In Any Quantity
Woodside, L. I., N. Y.
99
course, by far the simplest and best method of
"taking bearing" would be to stretch a piece of
string (not a steel wire piano string) across
from bearing bar or agraffe to sound board
bridge, at each point measure the relative
heights of the string above the surface of the
board and mark the bridge accordingly for
cutting.
Wholesale methods of "taking bearing" will
always be more or less inaccurate owing to
variations in the dimensions of the cast-iron
plates.
And lastly it may be pointed out that the
wooden bridges are always made higher than
they will ultimately become, in order to allow
for such variations in plate and case dimen-
sions.
"Bearing" in General
Now, having dealt with this important matter,
we may go on to consider the whole question
of "bearing" as related to sound board, bridges,
bearing bars, agraffes, tuning pins, hitch pins
etc.
Very little study has been given to the
subject, although it deserves the most careful
investigation, for it is extremely important in
its effect upon tone, stability of tuning, etc.
In the first place let me say with complete
assurance that the only object of providing
these differences in string levels which con-
stitute what we call "down" or "side" bearing
is the establishment of rigidity. The string
stretched at high tension receivea blows which
may be delivered with all the power of the
pianists arm enforced through his finger tips,
and so is in great need of rigid fastening. Yet
along with this the string must be arranged
so that, the tuner can increase or decrease its
tension at will without disturbing its power
to remain thus rigidly fastened. Hence the
otherwise rather unintelligible arrangements of
agraffes, staggered pins on sound board bridges,
capo d'astro bars, pressure bars, and so on.
"Bearing" in its various mechanical phases is
a matter of rigidity and of nothing else.
As such of course it is important, nay, es-
sential, although in the particular case which
I began by describing, the necessary bendings
of the wire could easily be made by mechanical;
arrangements on the sound board bridge, with-
out requiring the latter to be otherwise fitted.
(Continued on page 101)
and
Technicians
are in demand. The trade needa tuner*, reru-
latora and repairmen. Practical Shop School.
Send for Catalog hf
Y. M. C. A. Piano Technicians School
1421 Arch St.
Philadelphia, Pa
Future scanning projects are planned by the International Arcade Museum Library (IAML).