IMPROVEMENTS IN THE MANUFACTURE OF ARTICLES FROM CAST IRON
Year: 1864

page_text: LETTERS PATENT to Neil McHaffie, of Broad Street, Mile End, Glasgow,
Ironfounder, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF ARTICLES FROM CAST IRON."
PROVISIONAL SPECIFICATION left by the said Neil M Haffie at the
Office of the Commissioners of Patents, with his Petition, on the 20th
January 1864.
I, NEIL MCHAFFIE, of Broad Street, Mile End, Glasgow, Ironfounder, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF ARTICLES PROM CAST IRON," to be as follows:
This Invention is applicable more especially to the manufacture from cast
iron of articles which are required to combine great toughness with con-
siderable or great hardness, as, for example, projectiles (suitable for the pene-
tration of armour plates), plates, and slabs for batteries, dies of large size for
stamping metal, and many other articles.
I take cast iron of a very hard nature, by preference, white hoematite pig,
or a mixture of this with mottled or grey hoematite pig, which if cast in the
ordinary manner would be too hard to be conveniently cut and worked. For
many classes of castings it is found that all white pig-may be used, whilst in
other cases more or less of the mottled or grey pig may be mixed therewith,
and still produce castings of the requisite hardness. This metal I cast in a
mould of fire-clay or other material, which is kept heated in a furnace to a red

page_text: heat or hotter. The metal is run into the mould and is gradually cooled down
in the furnace. The gradual cooling of the metal ensures uniformity of
structure throughout the mass. Afterwards the article, although the metal is
still hard, can be turned and shaped if necessary. If greater hardness be
required the article (after turning and shaping, if these processes are resorted
to,) may be hardened by heating and plunging, as is practised when hardening
steel. The hardness also may, if required, be afterwards adjusted by a process
of tempering, as is practised with steel.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Neil McHaffie in the Great Seal Patent Office on the
20th July 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NEIL
MOHAFFIE, of Broad Street, Mile End, Glasgow, Ironfounder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of January, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Neil McHaffie, Her special licence that I, the said Neil McHaffie,
my executors, administrators, and assigns, or such others as I, the said
Neil M Haffie, 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, 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 ARTICLES FROM CAST IRON," upon the condition (amongst
others) that I, the said Neil M Haffie, 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 Neil M°Haffie, 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 :-

page_text: This Invention is applicable more especially to the manufacture from cast
iron of articles which are required to combine great toughness with con-
siderable or great hardness, as, for example, projectiles (suitable for the
penetration of armour plates), plates, and slabs for batteries, dies of large size
for stamping metal, and many other articles.
the mass.
I take cast iron of a very hard nature, by preference, white hoematite pig,
or a mixture of this with mottled or grey hoematite pig, which if cast in the
ordinary manner would be too hard to be conveniently cut and worked. For
many classes of castings it is found that all white pig may be used, whilst in
other cases more or less of the mottled or grey pig may be mixed therewith,
and still produce castings of the requisite hardness. I have found a mixture
of two parts of white and one part of mottled hoematite pig to be a good working
mixture. This metal I cast in a mould of fire-clay or other material, which
is kept heated in a furnace to a red heat or hotter. A mould of sand mixed
with a little lime I find suitable for many purposes. The metal is run into
the mould and is gradually cooled down in the furnace, the cooling being
made to occupy from 30 hours to 72 hours, or longer for very large sizes.
The gradual cooling of the metal ensures uniformity of structure throughout
Afterwards the article, although the metal is still hard, can be
turned and shaped, if necessary. If greater hardness be required the article
(after turning and shaping, if these processes are resorted to,) may be hardened
by re-heating and plunging, as is practised when hardening steel.
The
hardness also may, if required, be afterwards adjusted by a process of tem-
pering, as is practised with steel. The furnaces or ovens may be made of any
convenient forms, and the heat, by preference, used for the harder mixtures,
that is, with most white pig in the mixture, is from a full red to nearly a
white heat or even higher, and for the softer mixtures from a full red heat
down to a red heat. Castings from similar mixtures may be made in the
usual way, either in dry sand, green sand, or loam moulds, but instead of
letting them cool in the usual way they are taken out of the mould as soon
after solidifying as possible, and be placed in the furnaces or ovens heated, as
before mentioned, and then left gradually to cool, as in the former case. This
process does not usually produce such good results as pouring the metal whilst
the moulds are in the furnace or oven, but is sometimes more convenient.
What I claim is the making castings of white hæmatite iron, or a mixture
of this with mottled or grey, and very gradually cooling the said casting in an
oven or furnace, the moulds being placed in the furnace or oven and heated
before the metal is poured into them, or the castings being produced external.
of the furnace or oven and afterwards placed therein.

page_text: I also claim the hardening or the hardening and tempering castings made
from white hoematite iron (or a mixture of this with mottled or grey) and
gradually cooled, as described.
In witness whereof, I, the said Neil McHaffie, have hereunto set my
hand and seal, this Twentieth day of July, in the year of our Lord 5
One thousand eight hundred and sixty-four.
NEIL MOHAFFIE. (L.S.)