IMPROVEMENTS IN THE MANUFACTURE OF WHEELS OB TOOLS FOR GRINDING AND POLISHING SURFACES
Year: 1864

page_text: LETTERS PATENT to Edward Joseph William Parnacott, of Douro Street,
Fairfield Road, Bow, in the County of Middlesex, Mill Sawyer, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF WHEELS OB
TOOLS FOR GRINDING AND POLISHING SURFACES."
Sealed the 7th October 1864, and dated the 27th April 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 April 1864.
I, EDWARD JOSEPH WILLIAM PARNACOTT, of Douro Street, Fairfield Road,
Bow, in the County of Middlesex, Mill Sawyer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
WHEELS OR TOOLS FOR GRINDING AND POLISHING SURFACES," to be as follows:-
This Invention relates to a novel mode of preparing grinding and polishing
wheels composed of emery or other grit and a binding material, whereby their
efficiency and durability will be greatly increased. Hitherto in this class of
wheels the tendency has been for the wheels to glaze over and lose their
cutting property after being in work a short time, or they have worn away
very rapidly when this glazing tendency has been sought to be removed, or
the presence of oil or even water has been destructive to them; I now propose
to remedy all these defects, and to adapt wheels to special duties. In making
a cutting wheel I prepare a compound by mixing together emery, stone, grit,
and pounded clinker or other suitable grit with gold size, litharge, and white

page_text: lead, adding thereto a portion of lampblack. The proportions of these
materials may vary, but I find that the gold size or binding material when
forming about 3 of the mixture will ensure a good result. When thoroughly
combined I submit the compound to great pressure (using for the purpose an
hydraulic press) in a metallic mould suitably shaped to produce a wheel of
the required size, and into the mould I dust blacklead and fit therein loose
discs of tin, which will come out with the moulded wheel, and thus ensure its
easy delivery; by this means I obtain a very efficient and durable cutting
wheel. To produce what I term a soft wheel suitable for sharpening saws, for
which operation a wheel is required that will not jar against the saw teeth, I
prefer to use in place of the gold size a vegetable gum known as valata in
the proportion of about of the weight of the whole compound; I also omit
the use of litharge and white lead. The consolidation of the wheel, as in the
former case, I effect by pressure (comparatively slight) in an iron mould. To
prepare a buffing or polishing wheel, I use the finest kind of emery with fine
Bilston grit and clinker dust, and combine the same with gold size in about
the proportion or rather less than that stated above, using as before lampblack
and litharge, or in lieu of litharge burnt copperas; this compound well
mixed I submit to great pressure. In all these instances I obtain by the use of
pressure the required consolidation of the compound.
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 27th October 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
JOSEPH WILLIAM PARNACOTT, of Douro Street, Fairfield Road, Bow, in the
County of Middlesex, Mill Sawyer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of April, 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 Edward Joseph William Parnacott, Her special license that I,
the said Edward Joseph William Parnacott, my executors, administrators,
and assigns, or such others as I, the said Edward Joseph William Paruacott,
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

page_text: within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF WHEELS OR TOOLS FOR GRINDING AND POLISHING 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):-
This Invention relates to a novel mode of preparing grinding and polishing
wheels composed of emery or other grit and a binding material, whereby their
efficiency and durability will be greatly increased. Hitherto in this class of
composite grinding and polishing tools the tendency has been for the wheels
to glaze over and lose their cutting property after being in work a short time,
or they have worn away very rapidly when this glazing tendency has been
sought to be removed, or the action of oil or even water has been to destroy
them, now propose to remedy all these defects and to adapt composite wheels
or tools to special duties by manufacturing them in the manner which I will
proceed to describe. In making a grinding or cutting wheel I prepare a
compound by mixing together ground emery, stone, grit, and pounded clinker
or other suitable cutting substance with gold size and litharge or white lead,
which serve to bind the grit and harden the compound, and to this mixture
while in a plastic state I add a portion of lampblack or ivory black, which
serves to color the product and to separate somewhat the granules of cutting
substance employed. The proportions of these materials may vary, but I have
found the following to produce a good result. I take of fine emery two pounds
eight ounces, stone grit obtained from the stonemason's yard one pound eight
ounces, clinker dust eight ounces, lampblack or ivory black eight ounces, gold
size two ounces, and litbarge three ounces. This compound when thoroughly
combined I submit to great pressure in a metallic mould suitably shaped to
produce a wheel of the required shape and size. For moulding a wheel of
the form of a square-edged disc for example, I provide a divided ring having
lugs to receive screw bolts for bolding 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

page_text: 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 blacklead to prevent adhesion. 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 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 the hydraulic pressure:
On removing the mould from the press the metal discs will come out with the
moulded wheel, and thus insure its easy delivery. The pressure which I have
found sufficient to effect the proper consolidation of the compound is for a
wheel of six inches diameter about seventy tons, a proportionate increased
pressure being required for larger surfaces. Wheels thus produced I subject
to a heat of from three hundred degrees to four hundred degrees Fahrenheit
in any suitable construction of drying stove for about two hours, by which
means I expedite the ageing or drying of the wheels, it having been found that
their quality improves by ageing. To prevent the warping of the wheels under
this heat, I clamp them in iron moulds before placing them in the stove. The
like effect of ageing may be produced more slowly by hanging up the wheels
apart in a heated workshop. By these means I am enabled to obtain a very
effective and durable cutting wheel. To produce what I term a "soft
wheel" suitable for sharpening saws (for which operation a wheel is required
that will not jar against the saw teeth) I prefer to use in place of the gold
size a vegetable gum known as valata in the market. In this case I omit
the use of litharge or white lead, and although I effect the consolidation of
the wheel, as in the former instance, by pressure in an iron mould, I employ
by comparison a slight pressure (that is to say) to a wheel of twelve inches
in diameter, and three-eighths of an inch thick, 1 apply a pressure of about
fifteen tons. The proportions of the above-named materials which have been
found to give a good result are fine emery one pound, stone grit or mason's
dust two pounds, clinker dust twelve ounces, lampblack or ivory black one
ounce, and valata four ounces. The heat of the drying stove to which the
soft wheels are to be subjected will be in general about three hundred and
fifty degrees Fahrenheit. To prepare a buffing or polishing wheel I use tho

page_text: finest kind of emery with fine Bilston grit and clinker dust, and combine the
same with gold size in about the proportion or rather less than that stated
above, using as before lampblack or ivory black and litharge, or in lieu of
litharge burnt copperas. This compound when well mixed I mould as before
explained, submitting it to about the pressure above mentioned for the "soft
wheel" in iron moulds in order to obtain the required consolidation of the
compound.
Wheels or tools formed according to this Invention are adapted for grinding
every description of edge tools and cutlery, also spindles, files, cards used by
cloth dressers, and spiral cutters. They may also be beneficially employed for
trimming up castings in brass, gun metal, and iron and steel, by applying either
the periphery or the flat side of the grinding wheel to the article to be
trimmed. They may also be moulded in segments or in rings of any size
from one inch to three feet in diameter, and used for lapping and polishing
internal and external work. These wheels or tools admit of being used either
with or without water, and are suitable for cutting, shaping, or polishing
glass, marble, and every kind of hard or soft stone as well as for sharpening
all kinds of saws, grinding the hardest steel and other metallic surfaces.
Having now set forth the nature of my Invention of "Improvements in the
Manufacture of Wheels or Tools for Grinding and Polishing 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 the process
or processes above described for manufacturing grinding and polishing tools.
In witness whereof, I, the said Edward Joseph William Parnacott,
have hereunto set my hand and seal, the Twenty-sixth day of
October, in the year of our Lord One thousand eight hundred and
sixty-four.
E. J. W. PARNACOTT. (L.S.)