IMPROVEMENTS IN MAKING MOULDS FOR THE MANUFACTURE OF METALLIC SCREWS
Year: 1867

page_text: LETTERS PATENT to William Potts, of Handsworth, in the County of
Stafford, Manufacturer, for the Invention of "IMPROVEMENTS IN MAKING
MOULDS FOR THE MANUFACTURE OF METALLIC SCREWS."
Sealed the 21st April 1868, and dated the 28th October 1867.
PROVISIONAL SPECIFICATION left by the said William Potts at the
⚫ Office of the Commissioners of Patents, with his Petition, on the 28th
October 1867.
I, WILLIAM POTTS, of Handsworth, in the County of Stafford, Manu-
facturer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN MAKING MOULDS FOR THE MANUFACTURE OF METALLIC SCREWS," to be as
follows:-
The metallic screws of copying presses, bydraulic presses and machinery,
and of other articles, are ordinarily made from a rod of metal by means of a
lathe or other screw cutting machine.
My Invention consists in manufacturing the said screws by casting them in
moulds made in the manner and by the use of the apparatus herein-after
described, whereby great economy and facility of production are secured.
In making a mould for the manufacture of metallic screws according to my
Invention I proceed as follows:-I produce in the ordinary way and by the use
of the ordinary apparatus and materials a plain cylindrical mould of the length
of but somewhat less in diameter than the screw to be cast. I take a metallic
pattern screw of the size and shape of the screw to be made, one end of the

page_text: pass the
screw being taper for a short distance. To the said taper end of the pattern
screw a guide rod is affixed, and to the other end of the said screw another
guide rod with a handle is affixed, by which said handle the pattern screw
may be turned. To the opposite ends of the mould boxes in which the
cylindrical mould is made, and in a line with the said mould, bosses or
bearing are fixed in which the guide rods and pattern screw herein-before
described can work. After the cylindrical mould has been formed I
guide rods at the taper end of the pattern screw through the axis of the
mould in the mould boxes, until the end of the said rod is situated in one of
the bosses or bearings described on the mould boxes. When the guide rod is
in this position the pattern screw is situated in the opposite boss or bearing.
By now giving rotation to the pattern screw by its handle the said screw is
made to screw through the cylindrical mould, the conical end of the screw first
advancing and to form or mould the threads of the screw in the interior of the
cylindrical mould. A mould suitable for casting a screw is thereby produced.
As the pattern screw advances in the cylindrical mould its rectilinear direction
through the axis of the said mould is preserved by means of the guide rods
and the bearings or bosses in which the said guide rods and pattern screw
work. The pattern screw having been removed from the mould the necessary
gets for the passage of the molten metal into the mould and the vents
for the escape of the gases are made in the said mould, and the mould having
been dried is ready to receive the molten metal. When tubular screws are
required to be cast the mould is cored in the usual way. I prefer to cast the
screws of malleable iron or Bessemer steel, but other hard metal or alloy may
-be used.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Potts in the Great Seal Patent Office on the
25th April 1868.
TO ALL TO WHOM THESE, PRESENTS SHALL COME, I, WILLIAM
POTTS, of Handsworth, in the, County of Stafford, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date.the Twenty-eighth day of October, in the year of our Lord
One. thousand eight hundred, and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs, and successors, give and grant unto me,
the said William Potts, Her special license that I, the said William Potts,

page_text: my executors, administrators, and assigns, or such others as I, the said.
William Potts, 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; usė,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention' for "IMPROVEMENTS IN
MAKING MOULDS FOR THE MANUFACTURE OF METALLIC SCREWS," upon the con-
dition (amongst others) that I, the said William Potts, my executors or
administrators, by an instrument in writing under my; or their, or one of
their hands and seals, should particularly 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 William Potts, 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 thereof, that is to say :-
The metallic screws of copying presses, hydraulic presses; and machinery,
and of other articles, are ordinarily made from a rod of metal by means of a
lathe or other screw cutting machine.
My Invention consists in manufacturing the said screws by casting them in
moulds made. in the manner and by the use of the apparatus herein-after
described, whereby great economy and facility of production are secured.
In making a mould for the manufacture of metallic screws according to my
Invention I proceed as follows:-I produce in the ordinary way and by the
use of the ordinary apparatus-and materials a plain'cylindrical mould of the
length of but somewhat less in diameter than the screw to be cast with the usual
and necessary gets and air passages. I take a metallic pattern screw having a
taper figure. To the fore end of the pattern screw a guide rod with a handle
is affixed, by which said handle the pattern screw may be turned. At the
end of the mould boxes in which the cylindrical mould is made an adjustable
bearing, is so arranged as to be capable of being brought successively into a
line with each of a series of moulds where a series is employed. In this
bearing the guide rod and pattern' screw herein-before-described can work, or
if preferred the pattern screw may be furnished with a guide rod both at its
fore and at its rear end, each rod working in a bearing. After the cylindrical
mould has been formed I pass the guide rod at the taper end of the screw through
the axis of the mould in the mould: boxes, until the fore end of the said rod is

page_text: situated in the bearing described on the mould boxes. When the guide rod
is in this position the pattern screw is situated in the rear end of the cylin-
drical mould. By now giving rotation to the pattern screw by means of the
handle on the guide rod the said screw is made to screw through the cylin-
drical mould (the conical end of the screw first advancing), and to form or
mould the threads of the screw in the interior of the cylindrical mould. A
mould suitable for casting a screw is thereby produced. As the pattern screw
advances in the cylindrical mould its rectilinear direction through the axis of
the said mould is preserved by means of the guide rod or rods, and the
bearing or bearings in which the said guide rod or rods works or work. The
pattern screw is now removed from the mould which is then dried. When it
is dry the lower portion of each screw mould is closed with loam, and the
mould is then ready to receive the molten metal. When tubular screws are
required to be cast the mould is cored in the usual way. I prefer to cast the
screws of malleable iron or Bessemer steel, but other hard metal or alloy may
be used.
Having explained the nature of my Invention I will proceed to describe,
with reference to the accompanying Drawing, the manner in which the same
is to be performed.
Figure 1 represents in side elevation the mould boxes and apparatus which
I use in making the mould for the casting of two or more metallic screws;
Figure 2 is a longitudinal vertical section of the same; Figure 3 is an end
elevation of the same; and Figure 4 is a plan of the lower half of the mould,
the upper half being removed; the same letters of reference indicate the same
parts in each Figure of the Drawing.
.
a, b, are the mould boxes or half moulds clamped together by the screw
clamps c, c; d is the pattern screw having a taper figure, the said pattern
screw being fixed on the end of the guide rod e; the said guide rod e is
provided with a removeable handle f. To one end of the mould boxes a, b, a
bearing 9 is applied, the said bearing being situated in a line with the mould
to be made. In this bearing g the guide rod e works, as represented. in
Figures 1 and 2. The bearing g is capable of sliding on the end of the
mould boxes and of being brought opposite either of the holes h. By the
same sliding motion it can also be readily removed altogether from the moulds
or connected therewith. The manner in which the ends of the bearing g
engage in the slide 92 on the moulds will be understood by an examination of
Figures 1, 2, and 8.
In making moulds for the casting of two or more press screws I proceed as
follows: I take pattern rods of a diameter somewhat less than that of the

page_text: screws to be cast, and I lay these rods in the half mould boxes, each rod
being in a line with the openings h, i, and upon the said rods I form moulds
by ramming sand in the half mould boxes in the usual manner. The half
mould boxes are then clamped together in the manner represented, and plain
cylindrical moulds are thereby formed. The bearing g is now slidden opposite
one of the holes in the mould boxes, and having removed the handle f from
the guide rod e I pass the guide rod from the end A through the cylindrical'
mould and into the bearing 9, the pattern screw occupying the position
represented in Figure 2. Having reconnected the handle f to the guide rod e
and pattern screw d, I give a rotatory motion to the said rod and pattern
screw, and cause the said screw to screw through the cylindrical mould, and
to form or mould the threads of a. screw in the interior of the mould. As the
pattern screw d advances in the mould its rectilinear direction through the
axis of the mould is preserved by means of the guide rod e and bearing g, as
will be understood by an examination of Figure 2. When the pattern screw d
has screwed through the cylindrical mould and been brought into the bearing g
the said bearing is by a sliding motion detached from the mould boxes, the
handle fis removed, and the screw d and guide rod e are removed from the
bearing, and the said bearing is reconnected with the mould boxes and
brought opposite another cylindrical mould, when the operations described
are repeated and another screw mould is formed. The gets for the
passage of the molten metal and the vents for the escape of the gases are
made in the half moulds during the moulding of the first or cylindrical
moulds. After the screw moulds have been dried the lower portion of each
screw mould is closed by loam when the moulds are ready to receive the
molten metal, the casting process being conducted in. the ordinary way. In
Figure 4 two screw moulds k, k,, are made in the mould boxes, the gets for the
passage of the molten metal being marked l. When tubular screws are to be
cast the screw mould is cored in the usual manner. Figure 5 represents the
head of a pattern rod which I use to form the first or cylindrical mould when
vice screws are required to be cast. Instead of making the screw moulds in
ordinary mould boxes as described and represented the screw moulds may be
made in a mould box of a hollow cylindrical form, and the bearing for
supporting the guide rod may be fixed in a vice during the rotatory motion of
the pattern screw. This arrangement of my Invention is illustrated in
elevation in Figure 6 and cross section in Figure 7 of the Drawing. In the
said Figures 6 and 7 m is the hollow cylindrical mould box; n, the pattern
rods to form the cylindrical moulds; p is the pattern screw; 9, the guide rod,
and r the handle for turning it and the pattern screw; s is the bearing

page_text: for supporting the guide rod q fixed at the required height in the jaws t of a
vice. The hollow cylindrical mould box mis supported on any convenient
framing. After the rods n have been withdrawn the screw threads are made
in the cylindrical moulds in the manner described with respect to Figures 1,
2, 3, and 4.
The last-described arrangement permits a large number of screw moulds to
be formed in the same mould. box..
Although I find one guide rod and one bearing sufficient.to preserve.the
rectilinear direction of the pattern screw, yet, if desirable, a bearing may be
placed on either end of the mould boxes, and a guide rod be situated, on either
end of the pattern screw.
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 do not
limit myself to the precise details, herein described and illustrated, as the
same may be varied without departing from the nature of my. Invention.;, but
I claim as my Invention the improvements in making moulds for the manu-
facture of metallic screws, herein-before described and illustrated in the.
accompanying Drawing, that is to say, making the said moulds by first
moulding a plain cylindrical mould of the required size with or without a head,
and afterwards moulding the screw threads in the interior of. the plain.
cylindrical mould by screwing a pattern screw through the said mould,
substantially in the manner and by the use of the apparatus described and
illustrated.
In witness whereof, I, the said William Potts, have hereunto set my
hand and seal, this Twenty-first day of April, in the year of our Lord
One thousand eight hundred and sixty-eight.
WILLIAM POTTS. (L.S.)
Witness,
H. H. MURDOCH,
7, Staple Inn.