AN IMPROVED MANU- FACTURE OF ARTIFICIAL STONE APPLICABLE TO THE CUTTING OF METALLIC SURFACES
Year: 1864

page_text: LETTERS PATENT to Edward Joseph William Parnacott, of Leeds, in the
County of York, Mill Sawyer, for the Invention of "AN IMPROVED MANU-
FACTURE OF ARTIFICIAL STONE APPLICABLE TO THE CUTTING OF METALLIC
SURFACES."
Sealed the 27th December 1865, and dated the 27th October 1864.
PROVISIONAL SPECIFICATION left by the said Edward Joseph William
Parnacott at the Office of the Commissioners of Patents, with his
Petition, on the 27th October 1864.
I, EDWARD JOSEPH WILLIAM PARNACOTT, of Leeds, in the County of York,
Mill Sawyer, do hereby declare the nature of the said Invention for "AN
IMPROVED MANUFACTURE OF ARTIFICIAL STONE APPLICABLE TO THE CUTTING OF
METALLIC SURFACES," to be as follows:-
The object of this Invention is to obtain a factitious stone which may take
the place of the ordinary Turkey, water of Ayre, and Arkansas stones, used
for sharpening cutting tools and for kindred purposes. To this end I prepare
a compound which will admit of being moulded to any required form, and
when moulded may be hardened and brought to the consistency of stone.
In carrying out my improved manufacture, I take fragments and dust of
lithographic stone, and reduce it to fine granules. To this I add, say one-
sixth by weight (more or less) of fine emery powder and a smaller proportion
of borax and of saltpetre. Having well mixed these substances, I place the

page_text: compound in strong iron moulds, and subject the same to great pressure; I
afterwards submit the moulded articles to a high heat, which by fusing the
borax and saltpetre will effect the binding together of the granules of stone
and emerv
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Joseph William Parnacott in the Great Seal Patent
Office on the 26th April 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
JOSEPH WILLIAM PARNACOTT, of Leeds, in the County of York, Mill Sawyer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of October, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-eighth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Edward Joseph William Parnacott, Her special license
that I, the said Edward Joseph William Parnacott, my executors, adminis-
trators, and assigns, or such others as -I, the said Edward Joseph William
Parnacott, 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 "AN
IMPROVED MANUFACTURE OF ARTIFCIAL STONE, APPLICABLE TO THE CUTTING OF
METALLIC SURFACES," upon the condition (amongst others) that I, the said
Edward Joseph William Parnacott, by an instrument in writing under my hand
and seal, 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 Edward Joseph William Parnacott, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement (that is to say) :-
The object of this Invention is to obtain a factitious stone which may take
the place of the ordinary Turkey, water of Ayre; and Arkansas stones used for
sharpening cutting tools, and for kindred purposes. To this end I
prepare
a

page_text: compound which will admit of being moulded to any required form, and when
moulded may be hardened and brought to the consistency of stone.
In carrying out my improved manufacture, I take the chips and other
fragments and dust obtained in preparing the stones used for lithographic
purposes, and having reduced this refuse to fine granules, I add thereto
fine emery powder, borax, and saltpetre, and thoroughly mix them in
a suitable mill. The mixture thus obtained I-mould to any required shapes;
for example, cutting and polishing. tools, and I submit the same first to
hydraulic pressure, and then to furnace heat, whereby the hardness and con-
sistency of stone is imparted to the moulded articles.
Without confining myself rigidly to proportions, I would remark that the
following will produce a good result, viz.:-Take of pounded lithographic
stone twelve ounces, of borax two ounces, of saltpetre half an ounce, and of
very fine.emery two ounces. Place these substances together in an ordinary
incorporating mill with edge runners, (such as is used for preparing and mixing
mastic and sand) the pan of the mill being heated by means of steam or gas,
and subject the substances to the action of the mill until they are well mixed
and incorporated. Then remove the compound thus formed and place it in
strong iron moulds for the purpose of being submitted to pressure.
These moulds I make of various shapes and forms to suit the purposes for
which the artificial stone is to be used, and I propose to adopt any approved
construction. But when I desire to mould, say, for example, a cutting wheel
of the form of a square-edged disc, I adopt by preference the arrangement of
mould described in the Specification of my Patent, dated Twenty-seventh
April, One thousand eight hundred and sixty-four (No. 1062), that is to
say, I provide a divided ring having lugs to receive screw bolts. for holding
the parts together, and permitting of the ring being opened when required.
The inner diameter of this ring I turn to correspond to the diameter of 'wheel
required to be moulded, and to the under side of the ring I apply a plate,
securing the two together by screw bolts. This plate, which forms the bottom
of the mould, is provided with a central stud or core for moulding a central hole
in the wheel to receive the wheel spindle. The mould is placed on the plunger
of the hydraulic press, and immediately below a fixed block, which is intended
to enter the mould, and impart the pressure to the compound. Before placing
the compound in the mould, I drop into the mould a disc of tin, and I find it
convenient to cover this with a disc of wet brown paper. I then dust over
the sides of such mould powdered black lead, to prevent adhesion of the com-
pound. I now take a measured quantity of the compound, sufficient say to
produce a wheel of half an inch in thickness, and insert it in the mould. Over

page_text: this I prefer to lay a disc of wet brown paper of the diameter of the mould,
and above the paper I place a loose disc of tin of the same diameter, and
I then apply pressure to the mould. On removing the pressure from the
mould, the metal discs will come out with the moulded wheel, and thus insure
its easy delivery.
The pressure I have found necessary to effect a proper consolidation of the
compound may be conveniently given by means of a strong hydraulic press.
The amount of pressure which has proved satisfactory is about twenty tons per
square inch of surface of the moulded article. When the requisite mechanical
consolidation of the moulded article has been thus obtained, I subject the
moulded article to a white heat in any suitable construction of furnace, or to
such a heat as will serve to fuse the borax and saltpetre, and effect the binding
together of the granules of stone and emery.
As a guide to the operator I may state that the time required for attaining
this object will in general be from half an hour to one hour. To prevent the
warping and running of the moulded compound under this heat, I find it
desirable to clamp it in moulds made of plumbago, fire-clay, or other like
heat-resisting material, before placing the moulded articles in the furnace.
I would here remark, that when it is required to produce cutting or polishing
wheels, hones, or other like articles with a less cutting power than those made
from the before-named mixture I substitute ordinary chalk for a portion of
the lithographic stone granules. The proportions of the chalk and the granules
may vary, but I have found a proportion of half of each to produce a good
result, the proportions of the other materials mentioned above being retained.
Having now set forth the nature of my Invention of an improved manu-
facture of artificial stone, applicable to the cutting of metallic surfaces, and
explained the manner of carrying the same into effect, I wish it to be under-
stood that under the above in part recited Letters Patent I claim, manufacturing
artificial stone in the manner and for the purpose above described..
In witness whereof, I, the said Edward Joseph William Parnacott, have
hereunto set my hand and seal, the Twenty-fifth day of April, in the
year of our Lord One thousand eight hundred and sixty-five.