CERTAIN IMPROVEMENTS IN APPARATUS FOR CUTTING OR FORMING SCREWS, WHICH IS ALSO APPLICABLE FOR CUTTING PIPES OR TUBES
Year: 1865

page_text: LETTERS PATENT to Edward McNally, of Manchester, in the County of
Lancaster, Engineer, for the Invention. of "CERTAIN IMPROVEMENTS IN
APPARATUS FOR CUTTING OR FORMING SCREWS, WHICH IS ALSO APPLICABLE FOR
CUTTING PIPES OR TUBES."
Sealed the 14th November 1865, and dated the 23rd. May 1865.
PROVISIONAL SPECIFICATION left by the said Edward McNally at the
Office of the Commissioners of Patents, with his Petition, on the 23rd
May 1865.
I, EDWARD. MONALLY, of Manchester, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "CERTAIN IMPROVE-
MENTS IN APPARATUS FOR CUTTING OR FORMING SCREWS; WHICH IS ALSO APPLICABLE
FOR CUTTING PIPES OR TUBES," to be as follows:-
My Invention relates to mechanism for cutting or forming screwed threads,
and is designed for the purpose of cutting such threads either right or left
handed by the same cutter, the cutting edge being so directed and used as to
act similarly to a "chasing tool," that is, not to cut at right angles to the
thread, but at a more acute angle. The improvements consist in the use of a
cutter or screw-cutting instrument which is capable of being moved (as though
on & centre), so as to direct the cutting point either to the right or left of the
centre of pressure, which is to be at a right angle to the thread. This
may be accomplished by arranging the cutter in a sliding plate, to the outside
of and behind which the pressure is applied by thumbscrews or otherwise.
An internal aperture, in the shape of a segment of a circle, is formed in this

page_text: plate, in which aperture the cutter moves, the cutting point being nearest the
centre, and the opposite end being at the circumference of this segment; the
cutter being supported and prevented from falling out of this segmental
aperture by means of a curved rail or support beneath and extending across
the opening. Thus the cutting point being slightly in advance of the centre
of pressure by reason of the inclination or angle of the cutter, causes the thread
to be clearly and truly cut, similarly to being "chased" or cut in a "screw
cutting lathe," and in unscrewing the cutter from the thread the direction of
the cutter becomes altered, so as to leave a "clearance" and not to injure the
thread by the cutter acting upon it in the reverse or backward direction. The
material being operated upon may be supported between the cutter and other
"blank thread supporting pieces" opposite, or a series of cutters may be
arranged so as to cut and support simultaneously. This apparatus may also
be employed for severing pipes and tubes by substituting a single cutting point
or "diamond" for the screw cutter.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward McNally in the Great Seal Patent Office on the
23rd November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
MCNALLY, of Manchester, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of May, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Edward McNally, Her special license that I, the said Edward M'Nally, my
executors, administrators, and assigns, or such others as I, the said Edward
MoNally, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "CERTAIN IMPROVEMENTS IN
APPARATUS FOR CUTTING OR FORMING SCREWS, WHICH IS ALSO APPLICABLE FOR
CUTTING PIPES OR TUBES," upon, the condition (amongst others) that I, the
said Edward McNally, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly

page_text: describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward McNally, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following'
statement and accompanying Drawings (that is to say) :-
My Invention relates to mechanism for cutting or forming screwed threads,
and is designed for the purpose of cutting such threads either right or left
handed by the same cutter when applied to lathes, the cutting edge being so
directed and used as to act similarly to a "chasing tool," that is, not to cut at
right angles to the thread, but at a more acute angle; but when used in
stocks and screw cutting machines the die or dies will require altering
according to the thread to be cut. The improvements consist in the use of a
cutter or screw cutting instrument which is capable of being moved (as though
on a centre) so as to direct the cutting point either to the right or left of the
centre of pressure, which is to be at about a right angle to the thread. This
may be accomplished by arranging the cutter in a sliding plate, to the outside
of and behind which the pressure is applied by thumbscrews or otherwise; an
internal. aperture, in the shape of a segment of a circle, is formed in this plate,.
in which aperture the cutter moves, the cutting point being nearest the centre.
of the circle, and the opposite end being at the circumference of this segment,.
the cutter being supported and prevented from falling out of this segmental.
aperture by means of a curved rail or support beneath and extending across.
the opening, or by means of a flat plate enclosing the cutter. Thus the cutting.
point being slightly in advance of the centre of pressure by reason of the
inclination or angle of the cutter causes the thread to be clearly and truly cut
similarly to being "chased" or cut in a "screw cutting lathe," and in
unscrewing or returning the direction of the cutter becomes altered so as to
leave a "clearance" on that edge of the cutter that gave the downward cut,
the opposite edge of the cutter acting upon the upward cut or return action,
so as not to injure the thread by the space between the cutters acting upon it
as it commences the reverse or backward action. The material being operated
upon may be supported between the cutter and other "blank thread supporting
pieces" opposite, or a series of cutters may be arranged so as to cut and
support simultaneously by simply multiplying the aforesaid. The apparatus
may also be employed for severing pipes and tubes by substituting
cutting point or "diamond" for the screw cutter.
EL
single

page_text: In order that the Invention may be better understood and explained in
detail, I have hereunto attached a Sheet of Drawings made about half the
full size, similar letters of reference being marked upon corresponding parts
on all the Figures.
Fig. 1 represents a plan view of the improved "stock" or die holder, having
the top plate removed in order to exhibit the position and arrangement of the
dies and cutter employed to form or cut screw threads upon blank bolts or
other similar pieces of metal; Fig. 2 represent a side elevation of the same,
shewn complete; Fig. 3 represents a detached view of the "block" or cutter
holder in which the double-edged cutting die is inserted; Figs. 4 and 5
represent respectively a plan and elevation view of the screw cutter; Figs. 6
and 7 are similar views of the cutter employed for severing pipes or tubes;
and Fig. 8. represents a plan view of the cap or top plate for covering or
encircling the dies.
In Figs. 1 and 2 a, a, represents the block and handle of the "screw
stock," in which the recesses b, c, and d are formed to contain the dies; the
recess b in the block contains the cutter holder (seen in Fig. 3), and the
recesses c and d contain the supporting dies or "dummies" e, e. The-recess
or space formed in the block or cutter holder has an aperture widening towards
the cutter edge in order that the cutter (whether for forming screw threads or
severing pipes) may be reversed, so as to cut when turned either in a right or
left hand direction; for instance, when the cutter has descended to the lowest
part of its cut during the operation of forming a thread upon a blank bolt, the
reversing of the "stock"-at this time causes the cutter by its pressure on the
bolt to swivel and become reversed, thus bringing its opposite edge or cutter
into action, thereby giving an effective cut when returning in the direction of
unscrewing. The cutter when descending or in its downward action bears or
rests against the surface o of the cutter holder, and in its rising or upward
action the cutter becomes reversed and bears upon the surface o¹. The
cutter obtains its "feed" or pressure for cutting from the handle 9. which
is screwed into the stock, and becomes by that means forced against the
cutter holder, so as to propel it forward, or an ordinary thumbscrew may
be employed.
Having now described the nature of the said Invention, together with the
method of carrying the same into practical effect, I wish it to be distinctly
understood that I claim,-
First, the adaptation, employment, and of one or more dies, cutters, or
tools, each having two outting edges, and moving in the arc of a circle (as a
radius), so as to present one cutting edge in the first cut, and the other edge

page_text: in the second or returning in the direction of unscrewing, for the purpose
of cutting or forming screw threads or metal blanks.
Secondly, I claim the use and application to screw cutting lathes of cutters
having two cutting edges, and moving in the arc of a circle, so that screw
threads may be formed thereby both by the backward and forward motion of
the cutter.
And, lastly, I claim the employment and use in the same "stock" of one
or more cutters having two cutting edges and moving in the arc of a circle for
the purpose of presenting the cutting edge at a certain angle for cutting
or severing pipes or tubes, as herein-before described, set forth, and fully
illustrated in the Drawings attached.
In witness whereof, I, the said Edward M°Nally, have hereunto set my
hand and seal, this Twenty-second day of November, in the year of
our Lord One thousand eight hundred and sixty-five.
Witnessed by
JNO. L. DAVIES,
Office for Patents,
Manchester.
EDWARD MONALLY. (L.S.)