IMPROVEMENTS IN THE PRODUCTION OF STEREOTYPE PLATES AND IN APPARATUS EMPLOYED THEREFOR
Year: 1872

page_text: LETTERS PATENT to William Macrone and William McKenzie, both
of Glasgow, in the County of Lanark, North Britain, for the Inven-
tion of "IMPROVEMENTS IN THE PRODUCTION OF STEREOTYPE PLATES AND
IN APPARATUS EMPLOYED THEREFOR.”
Sealed the 27th August 1872, and dated the 25th June 1872.
PROVISIONAL SPECIFICATION left by the said William Macronc and
William McKenzie at the Office of the Commissioners of Patents,
with their Petition, on the 25th June 1872.
We, WILLIAM MACRONE and WILLIAM MCKENZIE, both of Glasgow,
in the County of Lanark, North Britain, do hereby declare the nature
of the said Invention of "IMPROVEMENTS IN THE PRODUCTION OF STEREO-
TYPE PLATES, AND IN APPARATUS EMPLOYED THEREFOR," to be as follows, that
is to say:
This Invention relates to improvements in what is known as the
"plaster of Paris" or "stucco" process for producing stereotype plates,
and it consists as follows:-
In taking a mould from the types according to the improvements
comprised under the present Invention, the surfaces of the types are first

page_text: covered with oil, after which a layer of wet "plaster of Paris" or
"stucco" having mixed with it some powdered red ochre and starch is
placed thereon, the mixture being forced thoroughly into the face of the
types by rolling and pressing it. Whilst still on the face of the types
a moulding frame consisting of a metallic plate planed or otherwise
rendered flat and smooth on both sides and having a ledge situated on
three of its edges is pressed on to the soft plaster mixture, the face
having the ledges being turned downwards, in which position it is left
until the plaster or stucco mixture has set, after which the whole is
lifted off the types, the plaster or stucco mixture forming the mould
adhering to the metallic frame, which on being placed in an oven or on
a hot plate to evaporate the moisture for a few minutes is ready for
casting.
In casting plates from the moulds prepared and arranged in frames
as herein-before described, any convenient number of them are bound
together in a series by cramps, the face of each such frame being next
to the back of the nearest frame to it in the series. The frames with
the moulds within them are then dipped into molten stereo metal which
fills into the spaces of the moulds, and after being allowed to cool the
cramps are withdrawn so as to allow the frames to be separated and the
plates withdrawn.
Plates produced by the improvements herein-before described and in
the improved frames, are obtained not only much more rapidly than
hitherto but they are also harder and more durable.
The essential features of these improvements are:- -The metallic
frames to back or support the moulds, thereby securing their thinness;
the thin moulds themselves; the composition for moulding; also the
using of a series of metallic frames for casting, as herein-before
described.
The approximate proportions of the ingredients preferred to be used
for the mixture herein-before described are "plaster of Paris" or "stucco,"
thirty parts, powdered red ochre two parts, and starch one part.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Macrone and William McKenzie in the
Great Seal Patent Office on the 23rd December 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
MACRONE and WILLIAM MCKENZIE, both of Glasgow, in the County of
Lanark, North Britain, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of June, in the year
of our Lord One thousand eight hundred and seventy-two, in the
36th year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said William Macrone and William M*Kenzie,
Her special license that we, the said William Macrone and William
McKenzie, our executors, administrators, and assigns, or such others as
we, the said William Macrone and William M'Kenzie, our executors,
administrators, or 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 THE
PRODUCTION OF STEREOTYPE PLATES, AND IN APPARATUS EMPLOYED THEREFOR,"
upon the condition (amongst others) that we, the said William Macrone
and William McKenzie, by an instrument in writing under our 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.
"3
NOW KNOW YE, that we, the said William Macrone and William
McKenzie, 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 and figures marked
thereon, that is to say :-
Our said Invention relates to improvements in what is known as the

page_text: And in order that our said Invention may be properly understood, we
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, that is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is a plan of a
type frame with the types set therein, and ready for taking a mould from
the types, according to the improvements comprised under this Inven-
tion; Figure 2 is a longitudinal section of the same on the line x, x,
Figure 1. As shewn by these Drawings, the types A are set in the type
frame B in the usual manner. In taking a mould from the types A
their surfaces are first covered with oil, after which a layer of wet.
plaster of Paris" or "stucco," having mixed with it some powdered
red ochre and starch, is placed thereon, the mixture being forced
thoroughly into the face of the types by rolling and pressing it.
66
Whilst still on the face of the types a moulding frame C, which is
shewn in side elevation at Figure 3, in plan at Figure 4, and in trans-
verse section on the line y, y, Figure 4, at Figure 5 of the Drawings,
consisting of a metallic plate planed or otherwise rendered flat and
smooth on both sides, and having a ledge a situated at three of its edges
is pressed on to the soft plaster mixture, the face having the ledges
being turned downwards and resting upon guage studs b, shewn at
Figures 1 and 2, which studs arc imposed along with specially cast
furniture c in the frame B with the type.
"
"
The type frame B is shewn in side elevation at Figure 6, and in plan
at Figure 7 of the Drawings, with the moulding frame C in position
thereon as pressed on to the soft plaster mixture covering the face of the
types A. In this position it is left until the "plaster or stucco
mixture has set, after which the whole is lifted off the types A, the
"plaster" or "stucco" mixture forming the mould adhering to the metallic
frame C, which an being placed in an oven or on a hot plate to evaporate
the moisture for a few minutes is ready for casting. The moulds by
being backed or supported by the metallic frames are formed thin and
are less liable to warp or crack, and the "plaster or stucco" mould is
obtained of a uniform thickness throughout, and is free from air holes,
which entirely saves the tedious process of "picking" as required by the
old "stucco process.
"
"
"

page_text: Having now described and particularly ascertained the nature of our
said Invention, and the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, we would
observe in conclusion, that what we consider to be novel and original,
and therefore claim as the Invention secured to us by the herein-before
in part recited Letters Patent is,―
First. The arrangement and construction of metallic frames supported
on guage studs, as illustrated on the appended Drawings, and the employ-
ment thereof in forming the thin moulds, and in casting stereotype plates
either singly or in a series, as herein-before described.
Second. Composing the thin moulds of " 'plaster of Paris" or
"stucco," red ochre, and starch, in proportions as herein-before
described.
In witness whereof, wc, the said William Macrone and William
McKenzie, have hereunto set our hands and seals, this Twenty-
first day of December One thousand eight hundred and seventy-
two.