IMPROVEMENTS IN EMERY OR CORUNDUM WHEELS, AND IN THE MODE OF MANUFACTURING THE SAME
Year: 1877

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
EMERY OR CORUNDUM WHEELS, AND IN THE MODE OF MANUFACTURING THE
SAME"
A communication from abroad by Isaac Payn Brown, the younger, of
Newark, New Jersey, in the United States of America.
aled the 22nd September 1877, and dated the 25th April 1877.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 25th April 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN EMERY OR CORUNDUM WHEELS, AND IN THE
MODE OF MANUFACTURING THE SAME." A communication from abroad by Isaac
Payn Brown, the younger, of Newark, New Jersey, in the United States of
America.
This Invention relates to improvements in the manufacture of emery or corundum
wheels with a base of celluloid or other equivalent composition which will yield to
the action of a solvent, and the object of the Invention is to make superior wheels
of this class more readily than heretofore.
In manufacturing celluloid grinding and polishing wheels it has been the practice
to dissolve pulverized celluloid in spirits of camphor, and to mix intimately with it
pulverized emery or corundum, then to press the plastic composition in a mould of
the desired shape of the wheel, and finally to dry the latter.
The drying process is a very tedious one, the thicker the wheels the longer being
the time required to dry. Even when apparently dry and hard the inner portions
of the wheel are frequently soft, and this necessarily detracts from the durability
of the wheel.
In order to obviate these difficulties the wheels are made, according to this
Invention, of a series of united discs or layers in the following manner:-For a
wheel of, say, 1 inch thick, are used, say, four layers each, one quarter of an inch
thick, or five, or even six layers of less thickness, each layer consisting of a disc of
the same diameter as the wheel to be produced; and each disc being made by com-
TDA77

page_text: pression in a mould in the usual manner. The separate discs are then dried, and
this drying may be readily accomplished owing to their thinness. After this each
disc is faced either by flatening it on a steam heated table or by turning it in a
lathe by means of a diamond tool, and then those faces of the disc which have to be
united are softened by applying thereto spirits of camphor, or other equivalent
solvent, and the collection of discs then subjected to a slight pressure. The result
of this will be a perfectly dry, hard, and homogeneous emery or corundum wheel,
in the manufacture of which much time has been saved, owing to the drying of the
discs before they are united to form the wheel.
Although celluloid has been alluded to above as the base of the wheels it will be
evident that the Invention is applicable to the manufacture of wheels of any
composition which will yield to a solvent after they are dry, and thereby enable a
complete junction of a number of discs to be effected.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 16th
October 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN EMERY OR CORUNDUM WHEELS, AND IN THE
MODE OF MANUFACTURING THE SAME." A communication from abroad by Isaac
Payn Brown, the younger, of Newark, New Jersey, in the United States of
America.
The said Invention relates to improvements in the manufacture of emery or
corundum wheels with a base of celluloid, or other equivalent composition, which
will yield to the action of a solvent, and the object of the Invention is to make
superior wheels of this class more readily than heretofore.
In manufacturing celluloid grinding and polishing wheels it has been the practice
to dissolve pulverized celluloid in spirits of camphor, and to mix intimately with it
pulverized emery or corundum, then to press the plastic composition in a mould of
the desired shape of the wheel, and finally to dry the latter.
The drying process is a very tedious one, the thicker the wheels the longer being
the time required to dry. Even when apparently dry and hard the inner portions
of the wheel are frequently soft, and this necessarily detracts from the durability of
the wheel.
In order to obviate these difficulties the wheels are made, according to the said
Invention, of a series of united discs or layers in the following manner:-For a
wheel of, say, about one inch thick, are used, say, four layers, each one quarter of
an inch thick, or five, or even six layers of less thickness, each layer consisting of a
disc of the same diameter as the wheel to be produced, and each disc being made by
compression in a mould in the usual manner. The separate discs are then dried,
and this drying may be readily accomplished owing to their thinness. After this
each disc is faced either by flattening it on a steam-heated table, or by turning it
in a lathe by means of a diamond tool, and then those faces of the discs which have
to be united are softened by applying thereto spirits of camphor, or other equivalent
solvent, and the collection of discs then subjected to a slight pressure. The result
of this will be a perfectly dry, hard, and homogeneous emery or corundum wheel,
in the manufacture of which much time has been saved owing to the drying of the
discs before they are united to form the wheel.
Although celluloid has been alluded to above as the base of the wheels it will be
evident that the Invention is applicable to the manufacture of wheels of any com-
position which will yield to a solvent after they are dry, and thereby enable a
complete junction of a number of discs to be effected.
Having now described and particularly ascertained the nature of the said Inven-

page_text: tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
First. The mode, herein described, of manufacturing an emery or corundum
wheel, that is to say, by preparing and drying thin discs, and subsequently uniting
the same in the manner described.
Secondly. As a new manufacture an emery or corundum wheel composed of
united discs, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Specifi
cation set my hand and seal, this Twelfth day of October, One thousand
eight hundred and seventy-seven.
J. HENRY JOHNSON. (LS)