IMPROVEMENTS IN THE CUTTERS OR CUTTING TOOLS OF SCREW WORMING MACHINERY
Year: 1876

page_text: LETTERS PATENT to Benjamin William Rogers, of Stourport, in the County of
Worcester, Machinist, for the Invention of "IMPROVEMENTS IN THE CUTTERS
OR CUTTING TOOLS OF SCREW WORMING MACHINERY."
Sealed the 18th July 1876, and dated the 6th March 1876.
PROVISIONAL SPECIFICATION left by the said Benjamin William Rogers at
the Office of the Commissioners of Patents on the 6th March 1876.
BENJAMIN WILLIAM ROGERS, of Stourport, in the County of Worcester, Machinist.
"IMPROVEMENTS IN THE CUTTERS OR CUTTING TOOLS OF SCREW WORMING
MACHINERY."
The cutters or cutting tools of screw worming machinery as ordinarily constructed
consist of a straight or curved bar of hardened and tempered steel, which has one
side of such a figure that in cross section the side referred to has the shape of the
portion of the screw blank which has to be cut away to form the thread or worm
of the screw; or the ordinary cutter or cutting tool has a figure proper to operate
on two parts of the blank at the same time, the parts so operated upon being the
parts of the blank which have to be cut away to form both sides of one thread, and
the opposite sides of threads on either side the said one thread.
My Invention consists in so forming the cutters or cutting tools of screw worming
machinery that they shall operate upon two parts of the blank simultaneously, each
of the two parts so operated upon being parts of the blank which have to be cut
away to form the opposed sides of two adjacent threads which are being in part
formed by one part of the cutter, are separated from the two adjacent threads
which are being formed by the other part of the cutter by a space equal to the
distance between the outer side of one thread and the outer side of the adjacent
thread; in other words, one part of the cutter is cutting away the portion of the
blank between, say, the first and second threads, while the other portion of the cutter
is cutting away the portion between the third and fourth threads, the part between
the second and third threads being operated upon for the travelling of the cutter.
Instead of operating upon two portions of the blank at the same time the cutter
may be formed to operate upon three portions of the blank at the same time,
the portions so operated upon alternating as described with respect to a double
cutter.
My improvements are applicable both to straight and curved cutters.

page_text: By my improvements a saving of time is effected in the cutting of the screw
thread, as a less number of cuts produces the required result than when ordinary
cutters are used, and my improved cutters do not require to be removed from the
machine so frequently for grinding as ordinary cutters do. Cutters made according
to my Invention produce a better form of screw thread than can be produced by
double cutters of the ordinary kind.
Although my Invention is especially applicable to screw worming machinery yet
it may also be applied to screw cutting or worming lathes.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjamin William Rogers in the Great Seal Patent Office on the 19th
August 1876.
BENJAMIN WILLIAM ROGERS, of Stourport, in the County of Worcester, Machinist.
" IMPROVEMENTS IN THE CUTTERS OR CUTTING TOOLS OF SCREW WORMING
MACHINERY."
The cutters or cutting tools of screw worming machinery as ordinarily constructed
consist of a straight or curved bar of hardened and tempered steel, which has one
side of such a figure that in cross section the side referred to has the shape of the
portion of the screw blank which has to be cut away to form the thread or wor
of the screw; or the ordinary cutter or cutting tool has a figure proper to operate
on two parts of the blank at the same time, the parts so operated upon being the
parts of the blank which have to be cut away to form both sides of one thread and
the opposite sides of threads on either side the said one thread.
My Invention consists in so forming the cutters or cutting tools of screw worming
machinery that they shall operate upon two parts of the blank simultaneously, each
of the two parts so operated upon being parts of the blank which have to be cut
away to form the opposed sides of two adjacent threads, but the two adjacent
threads which are being in part formed by one part of the cutter are separated from
the two adjacent threads which are being formed by the other part of the cutter by
a space equal to the distance between the outer side of one thread and the outer
side of the adjacent thread; in other words, one part of the cutter is cutting away
the portion of the blank between, say, the first and second threads, while the other
portion of the cutter is cutting away the portion between the third and fourth
threads, the part between the second and third threads being operated upon by the
travelling of the cutter.
Figure 1 of the accompanying Drawing represents a plan of my improved worming
cutter or worming tool in combination with a wood screw for exhibiting its action
upon the said screw. The acting end of the worming cutter or tool a is forked or
double, the two cutting parts being marked respectively b and c; the space d
between the two cutting parts b, c, of the cutter or tool is equal to the distance
between the outer side of one thread and the outer side of the adjacent thread, as
represented. By an examination of the Drawing it will be seen that the cutting
part 6 of the worming tool cuts away the metal of the blank to form the opposed
sides of the adjacent threads e, f, while the other cutting part c of the worming tool
cuts away the metal of the blank to form the opposed sides of the adjacent
threads g, h, the portion of the blank to form the opposed sides of the threads f, g,
being operated upon by the travelling of the cutter; thus it will be seen that the
cutter operates upon two parts of the blank simultaneously, so as to cut or worm
alternate threads on the blank.
Although for convenience of description I have spoken of the different parts of
the thread of the screw as separate or independent threads, yet it will be understood
that the several so called threads e, f, g, h, are different parts of one and the same
thread.
Instead of operating upon two portions of the blank at the same time the cutter

page_text: may be formed to operate upon three portions of the blank at the same time,
the portions so operated upon alternating as described with respect to a double
cutter. In this case, the cutter or worming tool instead of being forked or provided
with two cutting parts b, c, is provided with three cutting parts similar to the
parts b and c, the third cutting part being separated from the part 6 or c by a space
similar to the space between the parts b and c.
My improvements are applicable both to straight and curved cutters; a curved
cutter is shown in Figure 2.
By my improvements a saving of time is effected in the cutting of the screw
thread, as a less number of cuts produces the required result than when ordinary
cutters are used; and my improved cutters do not require to be removed from the
machine so frequently for grinding as ordinary cutters do. Cutters made according
to my Invention produce a better form of screw thread than can be produced by
double cutters of the ordinary kind.
Although my Invention is especially applicable to screw worming machinery, yet
it may also be applied to screw cutting or wormning lathes.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I claim as my Invention,
the improvements in the cutters or cutting tools of screw worming machinery
herein-before described, and illustrated in the accompanying Drawing; that is to
say, so forming the cutters or cutting tools of screw worming machinery that they
shall operate upon two parts of the blank simultaneously, each of the two parts so
operated upon being parts of the blank which have to be cut away to form the
opposed sides of two adjacent threads, but the two adjacent threads which are being
in part formed by one part of the cutter are separated from the two adjacent
threads which are being formed by the other part of the cutter, by a space equal
to the distance between the outer side of one thread and the outer side of the
adjacent thread; or constructing the cutter that it shall operate in a like manner
upon three portions of the blank at the same time, the portions so operated upon
alternating as described with respect to a double cutter.
In witness whereof, I, the said Benjamin William Rogers, have hereunto set my
hand and seal, this Seventeenth day of August, in the year of our Lord One
thousand eight hundred and seventy-six.
5 Witness,
S. Z. LLOYD,
Stourport.
BENJAMIN WILLIAM ROGERS. (L.S.)