IMPROVEMENTS IN SCREW STOCKS
Year: 1858

page_text: LETTERS PATENT to Thomas Chatwin, of Birmingham, in the County of
Warwick, Machinist, and Charles Taylor, of Birmingham aforesaid,
Machinist, for the Invention of "IMPROVEMENTS IN SCREW STOCKS."
Sealed the 20th August 1858, and dated the 10th June 1858.
PROVISIONAL SPECIFICATION left by the said Thomas Chatwin and
Charles Taylor at the Office of the Commissioners of Patents, with their
Petition, on the 10th June 1858.
We, THOMAS CHATWIN, of Birmingham, in the County of Warwick,
Machinist, and CHARLES TAYLOR, of Birmingham aforesaid, Machinist, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN SCREW STOCKS," to
be as follows:-
Our Invention consists in the methods herein-after explained of constructing
screw stocks used for cutting screws.
The said screw stocks contain three dies, situated in the said stock in the
directions of radii to the axis of the rod or bar, on which a screw is to be cut
by the said dies; one of the said dies is ordinarily stationary, and the other two
are made moveable, being capable of a sliding motion, so as to approach to
and recede from the stationary die; this motion is necessary during the cutting
of the screw, and also for the making of screws of different diameters, having
the same pitch of thread. We effect the sliding motion of the two moveable
dies in the following manner :-On the handle of the screw stock, and near

page_text: the body of the stock, a screw is cut, and a screw box or nut works on the
said screw. Two sliding bolts work in the body of the stock, the said bolts
respectively bearing at one end against the dies, and at the other end against
the screw nut; a washer is placed between the ends of the bolts and the screw
nut. On turning the screw nut the bolts are urged forward, and these cause
the moveable dies to advance; on turning the screw nut in the opposite
direction the dies are permitted to retire.
Instead of making a loose screw nut work on the handle, we sometimes make
the handle to screw into the stock, and by its advancing motion to urge
forward the moveable dies. We sometimes cause the three dies to advance
simultaneously. In this case a ring is made to screw into one face of the
stock, the said ring embracing the dies; the inner face of the ring, against
which the ends of the dies bear is inclined, and the ends of the dies bearing
against the ring are also inclined. By turning the said ring, so as to screw it
further into the stock, the inclined inner edge of the said ring wedges the dies
closer together, and on unscrewing the ring the dies are permitted to separate.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Chatwin and Charles Taylor in the Great Seal
Patent Office on the 7th December 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
CHATWIN, of Birmingham, in the County of Warwick, Machinist, and CHARLES
TAYLOR, of Birmingham aforesaid, Machinist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of June, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Thomas Chatwin and Charles Taylor, Her special licence that we, the said
Thomas Chatwin and Charles Taylor, our executors, administrators, and
assigns, or such others as we, the said Thomas Chatwin and Charles Taylor,
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 SCREW STOCKS,"
upon the condition (amongst others) that we, the said Thomas Chatwin and
Charles Taylor, our executors or administrators, by an instrument in writing

page_text: under our, or their hands and seals, or under the hand and seal of one of us or
them, should particularly describe and ascertain the nature of the said Inven-
tion, 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 we, the said Thomas Chatwin and Charles Taylor,
do hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
Onr Invention consists of the methods herein-after particularly described
and illustrated in the accompanying Drawings of constructing screw stocks
used for cutting screws.
The said screw stocks contain three dies situated in the stock, nearly in the
directions of radii to the axis of the rod or bar on which a screw is to be cut
by the said dies. One of the said dies is ordinarily stationary, and the other
two are made moveable, being capable of a sliding motion, so as to approach
to and recede from the stationary die; this motion is necessary during the
cutting of the screw, and also for the making of screws of different diameters,
having the same pitch of thread. We effect the sliding motion of the moveable
dies in the manner represented in Figures 1 and 2 of the accompanying
Drawings; Figure 1 being a plan, and Figure 2 a side elevation of a screw
stock made according to our Invention.
On the handle a of the screw stock and near the body of the stock a screw
6 is cut and a screw box or nut c works on the said screw b; two sliding bolts
d, d, work in holes in the body e of the stock, the said bolts d, d, bearing at
one end against the dies f, f, and at the other end against the washer g inter-
posed between the said bolts and the said screw box or nut c; on turning the
screw nut c in one direction, the bolts d, d, are urged forward, and the
moveable dies ff, are thereby caused to advance and approach the fixed die h;
on turning the screw nut c in an opposite direction, the dies f, f, are permitted
to retire.
Instead of making a loose screw nut work on the handle, we sometimes
make the handle to screw into the stock; and by its advancing motion to urge
forward the moveable dies.
This modification of our Invention is illustrated in Figure 3, in which said
Figure 8, i represents the handle of the stock, having a screw k formed at its
end. The end of the said screw bears against a cross bar 1, which in its
turn bears against the ends of the moveable dies m, m. By turning the
handle in a direction proper to drive home the screw k, the said screw

page_text: advances in the body of the stock, and pushes before it the cross piece l, and
dies m, m.
Figure 4 represents a modification of the screw stock last
described and represented in Figure 3. Instead of making a screw on the
handle of the stock, we cause a screw n to pass through the side of the stock,
the head of the said screw n acting upon the washer o, bolts p, p, and moveable
dies q, q, precisely in the manner described with reference to the screw box c,
Figures 1 and 2, that to say, the advancing and retiring motions of the
head of the screw n, effect the advancing and permit of the retiring of the
dies I, 9, in a manner precisely similar to that described with reference to the
screw nut c, Figure 1. We sometimes cause all three of the dies to advance
simultaneously. A screw stock constructed according to this modification of
our Invention is represented in plan in Figure 5, and in section in Figure 6.
Figure 7 represents a plan of the same with a portion removed. The three
dies are marked r, and the outer ends of the said dies are inclined as shown
at. The said dies r slide in radial slots formed in the body s of the stock.;
t is a ring, the outer cylindrical surface of which has a screw thread cut
thereon, which engages with the concave screw u, in the body of the stock.
The inner face of the ring t is inclined as shown at t¹, the said inner incliend
face t' bearing against the inclined ends of the dies 1. By turning the ring t
in a direction proper to depress it in the body of the stock, the inclined face t
of the said ring pressing upon the inclined ends of the dies 7, forces' them
towards the centre of the stock. By turning the ring t in a direction proper
to raise it from the body of the stock, its pressure upon the dies is relaxed, and
the said dies may recede from one another. Figure 7 is a plan of the screw
stock, having the ring t, Figures 5 and 6, removed. In order to facilitate the
screwing and unscrewing of the ring t, a series of notches are made in its edge;
these notches are marked v in Figure 5. A spanner w, the acting part 1 of
which is of a semicircular form, is used to effect the turning of the ring t,
The said spanner w has a claw a on its end, which may be made to engage in
one of the notches v, in the manner represented in Figure 5. Although it is
usually thought unnecessary to provide any arrangement for effecting the
return or retiring motion of the dies in screw stocks, yet we sometimes effect
the retiring motion of the said dies either by springs which force them back
when they are no longer pressed, or we connect the dies to the screwing
mechanism, by which they are pressed forward, so that on the retiring of the
said screwing mechanism, the said dies shall be withdrawn.
G
Having now described the nature of our Invention, and the manner of
carrying the same into effect, we wish it to be understood that we do not limit
ourselves to the precise details herein described and represented, as the 'same

page_text: may be varied without departing from the nature of our said Invention; but
we claim as our Invention,-
Firstly, the improvements in screw stocks herein-before described and
represented in Figures 1, 2, 3, and 4 of the accompanying Drawings, that is
to say, causing the moveable dies of a screw stock to advance either by the
advance of a screw box upon the screwed handle of the stock, or the advance
of a screw in the body of the stock.
Secondly, causing the several dies of a screw stock to advance simultaneously
by the use of a ring encircling the dies, the inclined inner face of the said ring
urging the dies forward, when the said ring is made to advance by a screwing
motion into the body of the stock, as herein-before described and illustrated
in Figures 5, 6, and 7, of the accompanying Drawings.
In witness whereof, we, the said Thomas Chatwin and Charles Taylor,
have hereunto set our hands and seals, the Sixth day of December, in
the
year of our Lord One thousand eight hundred and fifty-eight.
(L.S.)
CHARLES TAYLOR.
(L.S.)
Witness,
GEORGE SHAW.