IMPROVEMENTS IN DIE STOCKS FOR CUTTING SCREW THREADS
Year: 1883

page_text: LETTERS PATENT to Horbert John Allison, of the firm of Allison Brothers,
Patent Agents, Southampton Buildings, London for an Invention of
"IMPROVEMENTS IN DIE STOCKS FOR CUTTING SCREW THREADS" com-
municated to him from abroad by Charles Hart, of Cleveland, Ohio, United
States of America, Manufacturer,
PROVISIONAL SPECIFICATION left by the said Herbert John Allison at the
Office of the Commissioners of Patents on the 7th August 1883.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
Southampton Buildings, London "IMPROVEMENTS IN DIE STOCKS FOR CUTTING
SCREW THREADS," a communication to me from abroad by Charles Hart, of
Cleveland, Ohio, United States of America, Manufacturer,
The nature of said invention consists in part in the devices for holding or
guiding the stock in a central position upon the rod or bolt, on which the thread
is to be cut, whereby the threaded cutters will operate in the central line of the
article to be threaded.
The case or stock is provided with two arms or lovers for turning or rotating it
upon the bar or pipe in cutting the screw.
Attached to the side of the stock is an adjustable spring, and provided with a
pin, and arms connected also to the stock by means of screws or equivalents thereof
inserted through slotted openings in said arms. Upon one side or face of the case
or stock is connected an annular cam ring having a figured index or scale of sizes
marked thereon, and a series of peripheral notches or stops for adjusting and
setting the thread cutting dies to the various desired sizes. These several devices
which form a part of the improvements aro secured in position by means of an
annular ring which is so arranged as to fasten the said parts to cut a uniform
size of screws, but which can be so changed as to cut screws of various diameters.
The described constructions and arrangement in connection with the following
devices as set forth comprise the essential features of the said improved die stock.
On the cam ring before mentioned is an index or scale of sizes, which in connection

page_text: with an adjustable spring gauge, the screw dies may be set according to the
diameter of the bolt or pipe upon which the screw is to be cut.
The adjustable spring referred to is movably connected to the case with a pointer
extending from the spring to engage notches of the index on the cam ring, which
ring is provided with curved grooves upon its inner face terminating in short
radial grooves. These grooves engage a pin inserted in edge of the thread cutters.
On turning this cam ring, the said cutters are inoved and adjusted to the diameter
of the bolt or bar to be threaded, and the said cutters at the same time firmly
held in position by turning or screwing down the clamping ring upon the said
cam ring.
In the side of the shell are three openings into grooves to receive the thread
cutters, and in which they slide radially by means of the grooved cam ring before
mentioned. In the edge of this cam ring are also three openings into three-short
grooves connected with curved grooves in the face of the ring. These grooves in
the ring are arranged in such relations with the grooves in the shell, that the three
thread cutters will slide radially in the shell and cam grooves respectively and at
the same time by means of the cam ring when rotated. The openings into the
grooves of the shell and cam ring allow the thread cutters to be readily inserted
from the outside and withdrawn from the stock without taking the article apart.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Allison in the Patent Office on the 10th January
1884.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN DIE STOCKS FOR CUTTING
SCREW THREADS," a communication to me from abroad by Charles Hart, of
Cleveland, Ohio, United States of America, Manufacturer,
My invention relates to die stocks for cutting screw threads, as hereinafter
shown and described.
".
For a more full and complete description of the construction and operation of
the said invention, reference will be had to the following specification, and to the
annexed drawings, making part of the same.
1
In the drawings, Fig. 1, is a front view; Fig. 2, a side, view; Fig. 3, a
transverse section in the direction of the line 2-2, Fig. 1. Fig. 4, is a view of
the stop with screw-clamp and cam-plate removed. Fig. 5, is a view of the face
of the cam-plate, showing the cam grooves. Fig. 6, is a view of the threading dies.
Like letters refer to like parts in the soveral views.
To the shell or case A, of the die stock are connected sockets B, Figs. 1, 2, 3 for
the insertion of handles in using the said stock, in. the central portion of which is
an opening or aperture, C, to receive the rod or pipe on the side C₁ for threading.
This opening extends through from one side to the other, as seen in Fig. 3. The
exterior of the case is connected by a web, D, to the interior shell, E, within which
is the said opening C. On one side are formed grooves F, Figs. 2, and 4, in which
are made to slide tho thread-cutters G, and directly over the cutters is fitted the
cam-ring H, in which are curved cam-grooves I, Fig. 5. In these grooves are
loosely fitted the pins J, which project from the thread-cutters G, as soen in
Figs. 4, and 6.
'
By this arrangement of cutters G, in connection with grooves F, and the cam-
grooves I in the cam-ring H, the cutters are caused to slide radially in the
grooves F, on turning the cam-ring in the direction of the arrow, Fig. 1. The
grooves I, acting on the pins J, cause the thread-cutters G, to move toward
the centre of the opening C, and on a reverse motion of the cam-ring they slide
from the centre. In this way the thread-cutters are caused to move in radial lines
to and from the centre of the opening C, which admits of the said cutters being
adjusted to cut a thread on bolts or pipes of various diameters.
The thread or screw sections on the ends K, of the cutters, as seen in Figs. 3
and 6, cut the thread on the bar or pipe by turning the die or screw-stock in the
proper direction.
Directly over the cam-ring is a clamping-ring L, Figs. 1, 2, 3, the central
opening, C, passing through it, as seen in Fig. 1. On the inner edge of said ring
is formed an annular rabbet, in which is cut a thread, forming a threaded annular
rabbet, M, Fig. 3, which is screwed on the end or collar N, of tho interior shell, E,
the ring L, fitting down into an annular groove, O, in the upper sido of the cam-
ring H, as indicated in Fig. 3. By means of this clamp-ring L, in combination
with the threaded rabbet M, and the screw-collar N, the ring L, is. forced down
upon the cam-ring H, on turning it in the proper direction to engage the face of
the screws at M, N, and on turning the ring L, in an opposite direction the.
pressure, upon the cam-ring H, is removed, so that it may be turned in either
direction for sliding the screw cutters G. These cutters are securely held in the.
desired position so as to cut a series of bolts and pipes of the same uniform given

page_text: size, by forcing down the cam-ring H, upon the edges of the cutters G, which
cutters are clamped between the bottoms a of the grooves F, and the inside face, b,
of the cam-ring H, as indicated at a, and 6, Figs. 2 and 3. The width of the
cutters G is a little greater than the depth of the grooves F, so as to slightly project
above the face c, as indicated at b, and by the dotted line c, Fig. 3, to allow the 5
cam-plate to be pressed upon their edges.
For the purpose of holding the screw-stock in position upon the bolt or pipe,
and for guiding it in cutting the screws, there are connected with the stock three
guide-slides, P, Figs. 1 and 3, which are loosely fitted in grooves P¹ in the opposite
side of the stock from the grooves F. These slides are provided with pins which 1
are received in spiral grooves in the cam-ring Q, which is essentially the same in
construction and in its operation in moving the guide-slides P, in radial lines to
and from the centre of the opening C, as that described in relation to the cam-
ring H, and the thread-cutters G. The clamping-ring R, is provided with an
annular threaded rabbet, S, which is screwed on the threaded collar T, Fig. 3, and 1
loosely fitted into the annular groove U, of the cam-ring. On turning the cam--
ring Q, the guide-slides P, are adjusted to the diameter of the bolt or pipe to be
threaded, and are firmly held in such position by turning down the clamping-ring R,
on the cam-ring Q, which rests upon outer edges of the guide-slides, which are by
this means clamped between the bases d, of the grooves P¹ and the inner face of a
the said cam-ring Q.
--
The construction and operation of the described mechanism for setting and
moving the guide-slides P, are essentially the same as that herein sot forth for the
screw-cutters G. The slides P, are not threaded as are the cutters G. When the
guide-slides are once set for a pipe or bolt no further movement of the guides is a
required so long as the same uniform size of the bar or pipe is used for threading.
After the thread is cut the cutters G; are withdrawn from the bolt or pipe to
allow of the screw-stock being readily removed without unscrewing from the bolt,
as is the case in solid dies.
Connected to the side of the stock is a spring-gauge, V, in the arms e, of which
are slots e', and through which pass the thumb-screws f, f, Fig. 1, for the purpose
of attaching the adjustable gauge to the stock and to admit of its being moved in
the line of the slots. Near the free end of the gauge is a pin, g,, which catches into
the stops or notches h, Fig. 2, which stops are used in connection with. the
figures 1, 1, 1%, and 3, marked in the cam-ring, as seen in Fig. 1. The purpose
of this arrangement is for gauging or determining the size or diameter of the screw
to be cut, so that it will be at all times uniform, and in case of the screw-cutters
wearing away the gauge is moved correspondingly in the direction of the arrows,
Fig. 2, which is readily done by means of the slots e¹, e¹, on loosening the set
screws ff, which will cause more turn to be given to the cam-plate, thereby causing
the screw-cutters to be moved nearer to the centre of the aperture C, to contract
the diameter described by the worn-off cutters.
In case of new cutters being so adjusted in the die stock as to cut a one-inch
screw in diameter, then the cam-plate is turned in the direction of the arrow,
Fig. 1, to bring the desired stop h to the pin g. This stops the further movement
of the cam-plate by. the engagement of the stop h, and pin g, at which point the
cutters will cut a one-inch diameter bolt, and for one and one-fourth, one and one-
half, and so on, as marked on the cam-plate.
The stops or notches h at these points on the periphery of said plate are turned
to engage the pin g, which sets the screw-cutters to cut one and one-fourth or one
and one-half, etc., as the case may be.
As the cutters wear away in use the diameter of the cutters becomes enlarged,
and consequently the diameter of the screw. To reduce this enlarged diameter the
cutters must be moved toward the centre in proportion as they wear away. This
is obtained by moving the spring-gauge in the direction of the arrow, Fig. 2,
along the line of the slots e', e', which would cause the cam-plate to be turned
farther around in the direction of the arrow, Fig. 1, to allow the desired stop h,

page_text: and pin g to ongage. This additional movement of the cam-plate will cause the
Screw-cutters to be moved nearer to the centre-that is, to the original position or
diameter for a given size screw. By this means it will be seen that the same
uniform diameter can be given to the screws on moving the screw-cutters toward
the centre in proportion as they are worn away in use. The engagement of the
stop h, with the pin g can be adjusted, as before stated, to insure a uniformity in
the threads. When the screw is cut upon the bolt or pipo (which is entored in the
opening on the side C) the screw-cutters are drawn back sufficiently to allow the
screw-stock to be removed. The cutters are then again moved inwardly by turning
the cam-plate to the engagement of the stop and pin g, at some one of the figures
in the index or scale of sizes marked on the cam-ring, as seen in Fig. 1, according
to the desired diameter of the screw.
What I claim as my invention, and desiro to secure by Letters Patent, is :-
1. In screw-stocks, the adjustable spring-gauge V, provided with pin g, and
arms c, e, connected to said stock by means of screws inserted through slotted
openings e¹, e, in said arms, in combination. with the cam-ring H, having a figured
index or scale of sizes marked thereon and a series of peripheral notclics or stops, h,
substantially as and for the purpose set forth.
n
2nd. In a screw-stock, the combination of the cam-ring H, having a series of
peripheral notches or stops, h, h, clamping-ring L, and gauge V, provided with
slotted arms e, c, and spring-pin g, substantially as and for the purpose set forth.
3rd. The cam-ring H, provided with an index or scale of sizes and a series of
stops, h, in combination with tho adjustable spring-gauge V, arranged in relation to
the die stock and screw-cutters, substantially as and for the purpose described.
4th. The adjustable spring-gauge V, removably connected to the shell or case A,
in combination with the cam-ring H, provided with curved grooves for operating
the thread-cutters substantially as and for the purpose set forth.
5. The cam-ring H, provided with curved grooves terminating in radial
grooves I extending to the outer edge of said ring in combination with the
thread-cutters and shell A, substantially as and for the purpose set forth.
6th. The guide-slides P, cam-ring Q, clamping-ring R, in combination with a die
stock substantially as described and for the purpose set forth.
In witness whereof, I, the said Herbert John Allison, have hereunto set my
hand and scal, this tenth day of January in the year of our Lord oue thousand
eight hundred and eighty-four.
HERRERT T ALLISON