IMPROVEMENTS IN THE MANUFACTURE OP METAL CASTINGS
Year: 1852

page_text: LETTERS PATENT to James Ward Hoby, of Renfrew, in the
County of Renfrew, North Britain, Engineer, and John Kinni-
burgh, of Renfrew aforesaid, Foundry Manager, for the Inven-
Sealed the 17th May 1853, and dated the 26th November 1852.
PROVISIONAL SPECIFICATION left by the said James Ward
Hoby and John Kinniburgh at the Office of the Commissioners
of Patents, with their Petition, on the 26th November 1852.
We, JAMES WARD HOBY and JOHN KINNIBURGH, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE
OP METAL CASTINGS" to be follows:-
We prepare moulds for casting of refractory clay, either alone or
mixed with clean coarse grit or sand, or with plumbago or black
lead, or both of them, or with other suitable substance, and we
burn these moulds in the same way as fire brick in a kiln. The
clay is thus deprived of its plastic nature, and caused to cohere
with much greater strength than if it were merely dried in lieu of
being baked.

page_text: The moulds may either be made entire, or in pieces carefully
fitted together, and their faces may be made smooth before the
burning, or they may be carefully ground or rubbed out to the size
and shape required after burning them.
In using these moulds, a wash of plumbago is put on them, and
renewed between each cast.
In the case of piles and other regular shaped castings, these
moulds may be used either alone, in whole, or in separate pieces, or
in conjunction with other parts of moulds of sand or loam.
For pipes, the moulds may be made in one piece, or in two, or
more pieces, carefully rubbed together and fitted with a little lute
when a cast is to be made.
The mould being burnt, instead of merely dried, does not crack
with the heat of the melted metal.
By means of this Invention, a great number of castings may be
made in each mould, without destroying the mould, thereby reducing
the cost of production.
SPECIFICATION in pursuance of the conditions of Letters Patent,
filed by the said James Ward Hoby and John Kinniburgh in
the Great Seal Patent Office on the 24th May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
JAMES WARD HOBY, of Renfrew, in the County of Renfrew, North
Britain, Engineer, and JOHN KINNIBURGH, of Renfrew aforesaid,
Foundry Manager, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of November, in
the year of our Lord One thousand eight hundred and fifty-two,
in the sixteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto us, the said James Ward Hoby and
John Kinniburgh, Her special licence that we, the said James Ward
Hoby and John Kinniburgh, our executors, administrators, and
assigns, or such others as we, the said James Ward Hoby and John

page_text: Kinniburgh, 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 MANUFACTURE
OF METAL CASTINGS," upon the condition (amongst others) that
we, the said James Ward Hoby and John Kinniburgh, by an
instrument in writing under our hands and seals, or under
the hand and seal of one of us, 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 we, the said James Ward Hoby and
John Kinniburgh, do hereby declare the nature of the said Inven-
tion, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following state-
ment thereof; reference being had to the accompanying Drawing
and the figures and letters marked thereon (that is to say):-
The Invention relates to improvements in the manufacture of
metal castings by means of moulds made of clay, either alone, or
mixed with other substances, and baked or burnt previous to use.
We prepare moulds of fire clay, or of a mixture of fire clay and
clean coarse sand, or grit and plumbago, or of a mixture of fire clay
and sand, fire clay and common clay, fire clay and plumbago, or of
fire clay and any other suitable substance; and we burn or bake
these moulds at a red heat in a kiln, in a similar manner to that in
which fire bricks are burnt. The clay is thus deprived of its plastic
nature, and caused to cohere with much greater strength than if it
were merely dried in lieu of being baked. The mould is, in fact, a
piece of brick, and much better adapted for sustaining the sudden
contact of hot fluid metal than the dried clay or loam ordinarily
employed. The moulds may either be made entire, or in pieces
carefully fitted together, and their faces may be made smooth before

page_text: the burning, or they may be made smooth by grinding and rubbing
after they have been burnt or baked. The surface of the mould is
washed over with a mixture of plumbago and water, which is dried,
or allowed to dry, and the mould (when of more than one piece) is
put together, and the liquid metal poured into it. A small quantity
of lute or plastic clay may be placed between the junctions of the
different parts of the mould. When the metal has solidified, the
mould is separated, and the casting is removed. The mould is then
washed over again with plumbago, and put together again, and
another casting is made in a similar manner. Any slight injury
which the mould may sustain, may be repaired with ordinary loam,
and the mould may be employed in this manner for making several
castings in succession. In some cases it is advantageous to make
one portion of the mould in the manner above mentioned, and
another portion of the mould in the ordinary manner.
Figure 1, is a vertical section of a mould constructed according
to our Invention, and adapted for the manufacture of a cast iron
pipe. A, A, is the fire clay mould, which is divided longitudinally
into two semi-cylindrical portions. B, is the core made on a core
bar C, in the ordinary manner.
The lower end of the core is
fitted into the bottom of the mould A, which is contracted as
shewn in the Drawing. The mould A, rests upon a plate D, within
a ring d, d. The Plate D, is shewn in plan in Figure 2.
E, in Figure 1, is another plate, which is placed on the top of the
fire clay mould A, and connected to the bottom plate D, by three
bolts F.
gate
The top plate E, is shewn separately in plan in Figure 3. G, in
Figure 1, is the "gate box," which is filled with sand, in which
"gates" or passages are made for the introduction of the liquid
metal in the ordinary manner. Figure 4, is a plan of the "
box" G. e, is a ring or collar, supported by the fins f,f, and which
serves to maintain the upper end of the core in its proper position.
The "gate box" fits on to three pins g, in the top plate E. The
two portions of the mould A, A, are held together by hoops of iron
placed round them. These hoops are made in two pieces, united by

page_text: bolts and nuts. The mould so bound together may be placed in a
pit, and sand rammed around it. The inside of the mould is
warmed by a current of hot air, or in any other convenient manner,
and it is brushed with a wash of plumbago applied by means of a
long handled brush. The core is then introdnced, and the " "gate
box" put in its place. The fluid metal is then poured in. When it
has become solid, the core bar is lifted out of the mould, and the
pipe adheres to it, and separates from the mould by its own contrac-
tion. The mould is then brushed again with the plumbago wash,
and another core introduced.
In lieu of making the mould in two or more pieces, it may be
made in one piece when the casting is of such a form as to be
capable of being removed from it.
We have found that the fire clay is improved by the admixture of
about one fifth of its weight of sand, or old fire brick ground to
powder. The clay may also be mixed with plumbago in lieu of, or
in addition to, the last mentioned materials.
Moulds for pipes and other circular castings may be made by
means of a "sweep," or board turning upon centres in the ordinary
manner of preparing loam moulds. The sweep may be edged with
iron, in order to produce a smoother surface on the clay, as we find
it advantageous to make the surface as smooth as conveniently may
be before burning the mould in the kiln. When the mould is of
considerable height (as in the case of a mould for a pipe), it is built
up at intervals, so as to allow the clay in the lower part to settle,
as is practised in making pots or crucibles for melting glass. The
mould is burnt, or baked at a red heat, so as to destroy the plasticity
of the clay, and convert it into brick.
The wash of plumbago used for coating the surface, is made by
mixing powdered plumbago with water, or with beer, or yeast.
The ordinary "blacking" made with charcoal, and employed for
coating the surfaces of moulds of other descriptions, may be en-
ployed in lieu of the plumbago wash.
Having thus described the nature of the Invention, and in what
manner the same is to be performed, we claim, as the Invention

page_text: whereof the exclusive use is intended to be secured by the aforesaid
Letters Patent,
The manufacture of metal castings in manner herein-before
described by means of moulds made, wholly or partially of clay,
or of clay mixed with sand, plumbago, or other suitable substance,
and baked or burnt, so as to acquire the nature of brick, as
herein-before mentioned.
In witness whereof, I, the said James Ward Hoby, for myself
and the said John Kinniburgh, have hereunto set my hand
and seal, this Twentieth day of May, in the year of our Lord
One thousand eight hundred and fifty-three.
Witness,
THO' TAYLOR,
7, Wellington Row,
Bethnal Green.
JAMES WARD HOBY. (L.S.)