IMPROVEMENTS IN STOCKS AND DIES FOR CUTTING SCREW THREADS
Year: 1873

page_text: LETTERS PATENT to James Smart, of Old Ford, and John George
Fixter, of Hoxton, both in the County of Middlesex, Engineers, for
the Invention of "IMPROVEMENTS IN STOCKS AND DIES FOR CUTTING SCREW
THREADS."
Sealed the 11th November 1873, and dated the 20th May 1873.
PROVISIONAL SPECIFICATION left by the said James Smart and John
George Fixter at the Office of the Commissioners of Patents, with
their Petition, on the 20th May 1873.
We, JAMES SMART, of Old Ford, and JOHN GEORGE FIXTER, of
Hoxton, both in the County of Middlesex, Engineers, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN STOCKS AND DIES
FOR CUTTING SCREW THREADS," to be as follows :-
-
The object of this Invention is to construct stocks and dies suitable
for several sizes of screw threads, consisting of fewer parts and of a more
convenient construction than heretofore. For this purpose we make
each die with two or more cutting sides, but we prefer four sides. Each
cutting side has its required size of cutting thread. One of the dies is

page_text: The
fastened into the stocks by means of a bolt passing through it, which
at one end is formed square or otherwise to prevent the die from turning
while in use. This bolt may at the same time serve for fastening the
"link"
or loose side of the stocks on to the body of the same.
other dic has on each side a projecting pin, which fits and works in a
slot in the link and body of the stocks. To set up or regulate the
cutting by this latter die we prefer to use a wedge or a key passing
through the link and body bearing against the back of the die, and
formed with a screw at one end where a nut fits on, but other suitable
means for such purnose may be employed if preferred
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Smart and John George Fixter in the
Great Seal Patent Office on the 20th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
SMART, of Old Ford, and JOHN GEORGE FIXTER, of Hoxton, both in the
County of Middlesex, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing dato the Twentieth day of May, in the year
of our Lord One thousand eight hundred and seventy-three, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said James Smart and John George
Fixter, Her special licence that we, the said James Smart and John
George Fixter, our executors, administrators, and assigns, or such
others as we, the said James Smart and John George Fixter, our
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
"IMPROVEMENTS IN STOCKS AND DIES FOR CUTTING SCREW THREADS," upon the
condition (amongst others) that we, the said James Smart and John
George Fixter, our executors or administrators, by an instrument in writing
under our, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what

page_text: 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 we, the said James Smart and John George
Fixter, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, reference being had to
the accompanying Drawings and to the letters of reference marked
thereon, that is to say :-
The object of this Invention is to construct stocks and-dies suitable
for several sizes of screw threads, consisting of fewer parts and of a more
convenient construction than heretofore. For this purpose we make
each die with two or more cutting sides, but we prefer four sides. Each
cutting side has its required size of cutting thread. One of the dies is
fastened into the stocks by means of a bolt passing through it, which
at one end is formed square or otherwise to prevent the die from turning
while in use. This bolt may at the same time serve for fastening the
"link "
or loose side of the stocks on to the body of the same. The
other die has on each side a projecting pin, which fits and works in a
slot in the link and body of the stocks. To set up or regulate the
cutting by this latter die we prefer to use a wedge or a key passing
through the link and body bearing against the back of the die, and
formed with a screw at one end where a nut fits on; but other suitable
means for such purpose may be employed if preferred.
And in order that this our Invention may be more fully understood,
we will now proceed to describe the same with reference to the accom-
panying Drawings, which illustrate some modes of carrying it into
effect.
Fig. 1 is a plan; and Fig. 2, horizontal section through the middle of
stocks and dies constructed according to our Invention. A is the body
of the stocks cut out to receive the fixed die B and the movable die C,
which latter is moved or set up as required by means of a wedge or
key D formed with a screw and nut at one end for that purpose, as
shewn, or it may be done in any other suitable and well-known manner.
The die B is held in its place by means of a bolt E passing through it;
the bolt may at the same time, as here shewn, serve for fastening the
"link" or loose side F of the stocks, the stud G with its nut serving to

page_text: fasten the other end of the "link" F to the body A. This may however be
done in other ways; for instance, the body A may at that end be formed
with a projection for retaining the link, or the latter may be hinged on
to the body at that end. Both the dies B and C are here shewn with
three different threads on their three respective sides, and the fourth side
is formed with a half square notch or cut; and when the dies are turned
about, so as to bring the said half square cuts opposite one another the
stocks would serve as a tap wrench, as will hereafter be explained with
reference to Fig. 7. But all four sides may be formed with cutting
threads, if desired, or only two or three, and the others or other plain.
The die C is guided by means of a projecting pin on each side, which fits
and works the one in a recess in the link, and the other in a slot cut
through the back of the body, as shewn more clearly at Fig. 3, which
is a side view of the stocks with the link and dies removed; or instead
of a slot right through the body a recess may be formed in it, and the
projecting pin on the die made shorter to suit.
Fig. 4 is a plan view; and Fig. 5, a horizontal section through the
middle of stocks and dies made according to our Invention, but in a
somewhat different form. The die B is here held in its place by a round
projection or pin on each side fitting into corresponding recesses in the
body A, and the link F or the pins, or either of them, might pass
through holes passing right through instead of recesses. The link F is
held or fastened by means of two studs E and G, or it may at one end
be hinged on or be held by a projection on the body A, and at the other
by a stud or screw, or the link may be fastened in any other secure and
simple manner, so as to be easily detached when required. The dies are
here shewn with three sizes of screw threads on their three respective
sides, and with a half square notch on the fourth for the purpose of
making the tool serve as a tap wrench when the dies are so placed.
This is shewn on Fig. 7, which is a plan view shewing stocks and dies
according to our Invention, and with the dies so placed as aforesaid.
Fig. 8 is a plan; Fig. 9, a horizontal section; and Fig. 10, a side
elevation of stocks and dies of a somewhat different form, and more par-
ticularly suitable for cutting finer or smaller screw threads. The dies
are here made with five different sets of screw threads, as will be observed
from Figs. 11 and 12, which are respectively cross section and end
elevation of a die. The construction of stocks and dies is also such that
the dies can be turned in their places when required to change the

page_text: cutting threads without taking them out of the stocks A; B is tho
fixed die, which is held in its place by means of the bolt E, which
passes through it, serving at the same time as a means for holding the
link F, as already shewn and described with reference to Figs. 1 and 2.
The head of the bolt E is however here made with a head shaped some-
what like the "bit" of a lock key, the head being slightly recessed into
a corresponding notch or recess in one end of the die B and die C.
There are five such notches, both in the die B and in the die C, as
shewn by Fig. 12. By partly undoing the nut on the bolt E, and
pushing it back the head comes free of the dies B and C, which latter
then can be turned as required after the key D has been somewhat
slackened and pushed back. The movable die C has at each side a
projecting pin, which fits and works in a slot, or it might be a recess in
the side of the body A. and in the link F. The head of the bolt E is
made long enough to pass into one of the five notches in the die C, sec
Fig. 12, thus retaining the said die C in position while in use. The
link F is at one end retained in place by a projection of the body A of
the stocks fitting over a corresponding set off on the link, or it might be
attached or held by a hinge or other joint; its other end is retained by
the bolt E. When it is required to change the cutting thread the fixed
die B can be turned, as above described, by first partly undoing the
bolt E and pushing it back, and then turning the die by the hand as
required. The movable die O is also thereby loosened free to be turned
round by hand as required, but the key D must first be somewhat
slackened and pushed back. The part of the key which fits against the
large or flange part of the die C is hollowed out or otherwise formed to
suit the shape of the said part, which may be round or with a flat
opposite each cutting side, thus in this case round, as shewn, or
.

page_text: And having thus particularly described and ascertained the nature of
the said Invention for "Improvements in Stocks and Dies for Cutting
Screw Threads," we declare that we claim,-
Firstly. Forming dies for cutting screw threads with two or more
interchangeable sets of cutting threads, in order to cut two or more
different screw threads with one pair of dies, substantially as set
forth.
Secondly. The mode or modes of retaining and guiding the dies in the
stocks, substantially as set forth.
Thirdly. The construction of stocks, substantially as set forth.
Fourthly. The adaptation of stocks and dies constructed as set forth,
so as to form a tap wrench.
In witness whereof, we, the said James Smart and John George
Fixter, have hereunto set our hands and seals, this Twentieth
day of November, in the year of our Lord One thousand eight
hundred and seventy-three.
JAMES SMART.
(L.B.)
JOHN G. FIXTER. (L.S.)