IMPROVEMENTS IN MANUFACTURING INSTRUMENTS FOR SHARPENING KNIVES
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents, with his Petition, on the
16th May 1859.-A communication from abroad by Mr. Charles S.
Pomeroy, of New York.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN MANUFACTURING INSTRUMENTS FOR
SHARPENING KNIVES," to be as follows:-
In manufacturing the ordinary form of steels for sharpening knives, a piece
of steel forged into the usual shape was covered with scratches upon its surface
by means of a file, which method merely raised the grain of the metal by
scratching away particles of the steel, leaving the raised portions with torn
edges and irregularly formed, which after hardening soon wore off and left the
surface as smooth as before.
The present Invention consists in making upon the surface of a blank piece
of steel of the ordinary shape, or any other form which may be preferred for the
purpose, a series of continued longitudinal grooves with sharp edges between
them, formed by compression of the substance of the metal, by means of a
milling tool cut with sharp edges, as will be presently explained, thereby cutting
away none of the metal, but increasing its density, and rendering it, after being
hardened, much more durable and serviceable than the ordinary steel in the
use to which.it is to be applied in the sharpening of knives.

page_text: Instead of solid steel, wrought iron may in some instances be used for the
blank by being case-hardened after the edges have been impressed upon its
surface. The method of producing the sharp edges upon a steel, as above
referred to, is as follows:-The working parts of the apparatus are attached to
a rest that moves upon the bed of an ordinary lathe, and is actuated in its
motion between the heads of the lathe by a screw or other equivalent con-
trivance, and holding, by means of a set screw, the mechanism by which the
longitudinal grooving of the blank is effected; two levers moving on hinges are
pressed towards each other by a weighted cord or other equivalent contrivance.
These levers hold between them the blank steel, which is made to revolve by
the motion of the lathe being fixed between its two centres. In the upper part
of the lower lever is a semicircular recess in which the steel revolves, and is
thus kept steady; and immediately above, in the upper lever, is a rectangular
orifice to admit the milling tool. This tool is made of hardened steel, having
upon its periphery serrations, which are formed with sharp edges, thereby
differing from the ordinary milling instrument. The operation of the machine
is as follows:-The blank steel revolving in the lathe is held in equilibrio
between the two levers, and producing by friction a corresponding revolution
of the milling tool; by the pressure caused by the weight, the surface of the
blank is impressed with serrations, which are continued throughout its whole
length by means of the continued and regular motion of the slide rest, carrying
with it the milling tool, as before described, so as to produce a steel with the
longitudinal sharp edges desired.