IMPROVEMENTS IN CUTTING, BORING, GRINDING, AND PULVERIZING STONE AND OTHER HARD SUBSTANCES
Year: 1870

page_text: ETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical
Draughtsman, for the Invention of "IMPROVEMENTS IN CUTTING, BORING,
GRINDING, AND PULVERIZING STONE AND OTHER HARD SUBSTANCES." A
communication from abroad by Benjamin 'Chew Tilghman, of
Philadelphia, in the State of Pennsylvania, United States of America.
Sealed the 20th December 1870, and dated the 1st August 1870.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 1st August 1870.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Mechanical Draughtsman, do hereby
declare the nature of the said Invention for " IMPROVEMENTS IN CUTTING,
BORING, GRINDING AND PULVERIZING STONE AND OTHER HARD SUBSTANCES," to be
as follows:
-
This Invention relates to the cutting, boring, and grinding of stone,
metal, glass, and other hard substances, by means of a stream of sand,

page_text: (of quartz or other suitable material,) driven rapidly against them by a
jet of steam, air, water, or other suitable gaseous or liquid medium.
The greater the pressure of the gaseous or liquid jet the higher will be
the velocity imparted to the particles of sand, and the greater their cutting
effect upon the hard substances. The harder, specifically heavier, and
sharper the grains of the sand, the greater will be their cutting effect.
At a higher velocity of impact the grains of the sand will cut or wear
away substances much harder than the material of which the sand is
composed. When the sand used is of a brittle nature, such as quartz,
emery, or similar substances, the grains are broken by the shock into
fine powder, and the process may thus be used as a method of pulveriza-
tion. By varying the shape of the jets, and moving them or the stone,
cuts or holes of any shape or size may be made.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Vincent Newton in the Great Seal Patent
Office on the 1st February 1871.
. TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of August, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alfred Vincent Newton, Her special
licence that I, the said Alfred Vincent Newton, my executors, adminis-
trators, and assigns, or such others as I, the said Alfred Vincent
Newton, 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 CUTTING, BORING, GRINDING, AND PULVERIZING STONE AND
OTHER HARD SUBSTANCES," being a communication to me from abroad by
Benjamin Chew Tilghman, of Philadelphia, in the State of Penn-
sylvania, United States of America, upon the condition (amongst others)
66

page_text: that I, the said Alfred Vincent Newton, my executors or adminis-
trators, 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 Alfred Vincent Newton, 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, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon (that
is to say) :-
This Invention as communicated to me by my foreign correspondent
relates to the cutting, boring, grinding, dressing, and pulverising of
stone, metal, glass, wood, and other hard or solid substances by means
of a stream of sand, or grains of quartz, or of other suitable material
artificially driven, as projectiles rapidly against them by a jet of steam,
air, water, or other suitable gas or liquid, which jet may be made to
ornament glass and other polished surfaces by partially depolishing such
surfaces so as to produce any desired pattern thereon.
The following is the description of the process as communicated to
me: The greater the pressure of the jet the higher will be the velocity
imparted to the grains of sand, and the 'more rapid and powerful their
cutting effect upon the solid substance. At a high velocity of impact
the grains of sand will cut or wear away substances much harder than
themselves, corundum can thus be cut with quartz sand, and quartz
rock can be cut or worn away by small grains or shot of lead, I have
sometimes used iron sand composed of small globules of cast iron.
By the term sand in this Specification I mean small grains or particles
of any hard substance of any degree of fineness, of which common
quartz sand is a type. The hardest steel, chilled cast iron, or other
metal can be cut or ground by a rapidly projected stream of quartz sand.
Articles of cast or wrought metal may have their surfaces thus smoothed
and cleaned from slag, scale, or other incrustation, and this method of
cleaning may be used in preparing metals for being tinned, zinced,
enamelled, or coated with metallic or other substances. The surfaces
of wrought stone, in buildings or elsewhere, can thus be cleaned and

page_text: refreshed. By means of stencil plates, screens, or suitable covering
substances, letters or designs can thus be cut or engraved upon hard
substances. By varying the shape, number, and direction of the pro-
jected streams of sand, and by giving to them and to the articles treated
suitable movements by means of lathes, planing or drilling machines,
or other known mechanical devices, cuts or holes may be made of any
shape or size.
When sand of a brittle nature, such as quartz or emery,
is very rapidly projected against a hard material the grains are broken
by the shock into fine powder, and the process may thus be used as a
method of pulverization. Where a jet of water under heavy pressure
is used, as in hydraulic mining, the addition of sand will cause it to cut
away hard and close grained substances, upon which the water alone
would have little or no effect. Pebbles or stones of size and weight as
great as can be rapidly projected by the jet of water used will have a
battering, penetrating, and dislocating effect which will assist the dis-
integrating and scouring action of the water.
Heretofore when sand has been used as a grinding or cutting material
it has been applied between solid substances moved over each other
under heavy pressure so as to make a series of scratches as in the ordinary
cutting of stone and glass, or else in a solidified form as in a grindstone
or sand paper, or sometimes in a semi-fluid state as when a body is rubbed
or moved in a mass of sand.
The peculiar feature of my Invention, which distinguishes it from
other methods of cutting and grinding, is that each grain of sand acts
by its own velocity and momentum like a bullet or projectile, and
pulverizes, cuts, or indents the object it strikes. From this peculiarity
of action it results that some substances which though comparatively
soft are also tough or malleable or elastic, and not pulverizable by
a blow such as copper, lead, paper, wood, or caoutchouc, for example,
are less rapidly cut and ground by the sand blast particularly at
moderate velocities, than some much harder substances which are
brittle or pulverizable such as stone, glass, or porcelain. Another
peculiarity of the sand blast is that the grinding or cutting action. takes
place upon irregular surfaces, cavities, corners, and recesses, hardly
accessible to ordinary methods. I believe that steam will generally be
found the most convenient impelling jet, particularly for high velocities,
but in some localities air or water may be cheaper. I have used steam
of all pressures, sometimes exceeding four hundred pounds per square

page_text: inch, and have found its efficiency to increase with the pressure. I
believe that when it is desired to cut or grind hard substances rapidly it
will be advantageous to use steam of as high pressure as can practically
be made available, but each operator can choose the pressure most
convenient for his circumstances and the kind of work he wishes to do.
The following is a method of carrying my Invention into effect, taking,
for example, the cutting of stone by means of quartz sand projected by a
jet of steam of about three hundred pounds pressure per square inch.
In the accompanying Drawing Fig. 1 shews in partial sèction the
arrangement of jet apparatus employed in carrying out the Invention.
The sand is fed into a funnel a, which is connected by a flexible. tube
and turning point 6 with an iron or steel tube c, c, of any convenient
length and of about seventeen-hundredths of an inch bore, which I call
the sand tube; this tube is firmly secured exactly in the centre of
another iron or steel tube d, d, of about one-half inch bore, which I call
the steam tube. The interval between the tubes is closed at one end e;
at their other ends both tubes are brought to the same length, but the
bore of the outer tube d is here contracted to a diameter of twenty-six-
hundredths of an inch for about one quarter of an inch from its end, and
about half an inch of the end of the inner tube c, is reduced to a cylinder
of twenty-three-hundredths of an inch external diameter, so as to leave.
between the ends of the tubes a smooth regular annular opening m, m,
of about fifteen-thousandths of an inch in width, continuing of this size
for about a quarter of an inch in length and then enlarging gradually to
the full diameter of the steam tube; this annular opening m, m, forms the
passage for the escape of the steam. The steam tube d is connected
with the steam boiler by the holes f, f, the T piece g, the stuffing boxes
h, h, h, and the jointed pipes o, o, o, so as to allow it to be rotated and
moved in any direction. A wrought or chilled cast iron or steel tube i, i,
which I call the nozzle tube, about thirty-eight-hundredths of an inch in
bore and six inches long is fastened on the end of the steam tube. The
end of the sand tube c is accurately adjusted and firmly fastened exactly
in the centre of the steam tube d, so that the annular opening is every-
where of the same width, and the nozzle tube is adjusted so that its axis
or central line coincides perfectly with the axis of the steam jet issuing
from the annular opening. The perfect accuracy of these adjustments is
important. The bore of the nozzle tube is adjusted by trial to the size
and pressure of the steam jet so as to produce the amount of suction

page_text: 66
the
desired in the sand tube. For the sake of brevity the stream of sand
impelled by the jet of steam, air, &c., will herein be called "the sand
blast," and the system of tubes for producing it will be called
blast pipe." The sand used should be sifted of even size, and should be
clean, hard, sharp, and dry, so as to run regularly through a small hole
without clogging. I have found sand which will pass through a sieve of
forty wires per inch and not through one of forty-eight wires to cut
faster than sand which will pass through a sieve of twenty wires and not
through one of thirty wires to an inch. The steam should be dry and
free from condensed water. When used at a distance from the boiler a
steam separator or purger should be used such as is well known to
engineers and the pipes kept well wrapped.
The operation is as follows:-The steam is turned on and issues with
great velocity from the annular opening m, m; this creates a suction and
current of air in the sand tube c, c. A sliding valve in the bottom of the
sand box is now opened and lets a stream of sand of from one to two
pints per minute fall into the funnel a, whence it is carried by the
current of air through the sand tube, and is sucked into the jet of steam
and driven by it through the nozzle tube, acquiring a high velocity, and
finally strikes against the stone to be cut, which is held about an inch
distant from the end of the nozzle. The shattered fragments of the sand
and stone, partly in very fine powder, and the waste steam escape sidewise
and backward. A dull red light may be seen at the point of impact of
the sand and stone. If the sand blast is kept directed steadily at the
same spot a hole will gradually be cut, the diameter of which at the
surface is greater than that of the steam jet, but which grows smaller and
becomes conical as it penetrates deeper into the stone.
I have observed that this tendency to form a conical hole increases
with the hardness of the substance operated on, and that it diminishes as
the pressure and velocity of the blast is increased. To make a hole or
cut with parallel sides I have found that the blast should be slightly
inclined towards each side alternately. The angle of inclination will
vary with the hardness of the stone and the pressure of the jet used.
In cutting granite with a steam jet of about three hundred pounds
prèssure per square inch, I have found an inclination of about one in
nine to make a parallel cut. Operating on rather soft burnt brick with
the same jet, without inclination, the sides of the cut were almost parallel.
Sufficient space must always be allowed for the escape of the current of

page_text: waste steam and sand, and consequently when a deep hole is to be cut
its diameter must be great enough to admit this escape around the
blast pipe when it is advanced to near the bottom of the hole.
In cutting holes I have found it convenient to use a blast pipe bent
at a point about two inches back of the annular jet to an angle of
about one in nine, and to use a nozzle tube only about two inches long.
The blast pipe being directed as above indicated successively to all
parts a hole of any shape can be cut with parallel sides, or the sides may
be undercut so that the hole will be of greater diameter at the bottom
than at the top, chambers for blasting powder may thus be made.
In cutting long narrow grooves I have found it convenient to arranged
parallel guide plates of iron or steel n, n, (see detached view Fig. 1")
about one and a half inch wide and projecting about three inches from
the end of the nozzle tube, leaving between the plates a space equal in
breadth to the bore of the nozzle tube. The effect of these plates is to
prevent the sand blast from diverging, and to make the edges and surface
of the groove more even and regular.
In dressing stone so as to produce a flat. surface I have found it
convenient to cut first a narrow groove about half an inch deep, and
then to break or split off the overhanging edge, and then continue or
deepen the groove, and break off the new overhanging edge, and so on.
When the stone varies in hardness in different spots the workman must
keep the blast directed upon the hard spots until he sees that they are
worn down to the desired level, and must pass it quickly over soft spots as
soon as he sees they are sufficiently cut. As most kinds of stone contain
frequent alternations of hard and soft spots constant care and attention
must be given by the operator to obtain an even surface. A sheet iron
guard or shield is arranged to protect the face and eyes of the workman
from the rebounding sand, and a narrow slit in it enables him to watch
and regulate the progress of the opération. Suitable movements are to
be given to the blast pipe or to the stone, or to both, by hand. or by any
suitable machinery so as to produce the shape of cut desired. If the
axis of the nozzle tube and guide plates does not coincide accurately
with that of the steam jet they will be rapidly cut away by the sand
blast. If any obstruction from dirt or scale chokes up one side of the
annular opening of the steam jet the sand blast will be distorted sidewise
and will rapidly cut away the nozzle tube. Even under good conditions
the sand blast will gradually cut away the nozzle tube, which must be

page_text: watched and renewed when required. Instead of an annular impelling
jet having the sand introduced in its centre I have sometimes used a
central impelling jet and introduced the sand by an annular tube
surrounding the impelling jet.
I have found the above described method of introducing the sand
into the impelling jet by means of the suction produced by the jet
itself to give good results, but it is to be understood that I do not
confine myself thereto. I am aware that part of the pressure of the jet
is thereby lost, but I think the practical convenience counterbalances
this loss, I have sometimes used a strong close vessel to contain the sand,
and introduced a current of the steam, air, or water, under pressure,
above the sand, and then by suitably regulating the cock on the pipe
leading to the top of the close vessel and the cock on the pipe leading
to the impelling jet a current of the fluid can be made to pass through
the close vessel and carry with it any desired quantity of sand into the
impelling jet. When steam is used in this manner the close vessel
must be kept hot enough to avoid the condensation of water among the
sand which would prevent its running through the pipes. A current
of air forced into the close sand box at a pressure greater than that
of the steam employed may also be used as a means of conveying the
sand into the impelling steam jet. I have observed that the quantity of
stone cut by a given sand blast in a given time is much greater when
ample space for free escape is afforded to the sand and steam after they
have struck the stone than when the space for escape is narrow and
confined. When a rapid lateral motion is given to the blast pipe or to
the stone so that the sand is constantly striking upon a fresh surface
a much greater cutting effect is produced than when the blast is kept
pointed at one spot. In the latter case it appears that the sand and
steam rebounding back from the stone interfere considerably with the
fresh sand which is being projected toward the stone. This interfering
effect is particularly evident when a hole is cut but little larger than
the diameter of the sand blast. I have noticed that when a sand blast
is held at four or five inches distance from a stone a greater quantity
will be cut than when the same sand blast is held at but one inch
distance. Also that when a sand blast is directed at an angle of from
thirty to forty-five degrees with the face of a stone a greater quantity
will be cut than when the same sand blast at the same distance (one
inch) is directed at an angle of ninety degrees with the face of the stone.

page_text: The divergence of the sand blast spreading it over a wider surface of
the stone and also giving it more room to escape, and thus to avoid
interference with the oncoming sand appears to be the explanation in
these cases.
But I have found that in cutting a narrow groove more
progress is made by keeping the blast pipe directed square at the stone
and keeping the stone as close to the guide plates as its shape will
permit, for although the gross quantity of stone cut away may be less
than at a greater distance the effect is more concentrated and confined
to the desired spot and direction. The quantity of sand to be used with
a given steam jet may be considerably varied according to the object
desired. When a soft stone is to be cut over a wide surface, so that a
free sideway escape can be given, a' quantity of sand two or three times
as great as above described may be used, but where a hard stone is
to be cut in a narrow groove a small feed of sand produces a better
result.
I have found the proportions, size, and arrangement of tubes com-
posing the blast pipe above described to give good results in practice
under the conditions mentioned, but I do not mean to confine myself
thereto as they will vary according to the pressure of the jet used, and
the kind of work to be done in order to obtain the best results in
economy of power and time. The principal points to be attended to
are, first, to get an impelling jet of great velocity; second, to feed the
sand regularly and in such a manner as to acquire as nearly as possible
the velocity of the impelling jet; third, to direct the projected sand upon
the desired spot without wasting its force in wearing away the nozzle
tube; and, fourth to provide free escape for the expended steam and
sand so as to avoid back pressure and interference. For purposes where
only a small quantity of material is to be cut or ground away from the
surface of a hard substance, and where only a moderate velocity of
the sand is required, I have found the current of air produced by the
ordinary rotary fan to be convenient. I have used this method for
grinding or depolishing glass, china, or pottery, either on entire surfaces
or on surfaces partially covered and protected so as to produce an.
engraving of letters, ornaments, or designs. In engraving designs air
is more convenient than steam as an impelling jet in this respect that
the sand keeps dry and rebounds leaving the pattern clear, while with
steam the sand becomes damp and is apt to adhere to and clog the fine
lines and corners. The sand being fed into the air current by its own

page_text: moved oposite the mouth of the trunk, and cuts, grinds, or stars its
surface.
One arrangement which I have found convenient for flat glass is
shown in longitudinal and transverse section in Figures 2 and 3 of the
Drawing, but I do not confine myself thereto, as the mechanical arrange-
ments may be varied. The air current from the fan of about the
pressure of four inches of water is brought by the trunk a, a, (about one
foot high and two feet wide) and descends into the narrow vertical
tube b, b, (about two feet high and of a cross section of about sixty
inches long by one inch wide) from the lower end of which it rushes
with a velocity proportioned to its pressure. Into the upper end of the
tube b, b, the sand is evenly fed from the sand box c by means of the
sand tube d, d, (about one foot high and of a cross section of sixty inches
by one half inch), the lower end of which is closed by an iron plate
perforated with holes about a quarter of an inch in diameter, and half an
inch apart, so as to supply about fifteen or twenty cubic inches of sand
per minute to each square inch of cross section of the air tube b, b. In
passing down the tube b, b, the sand acquires a velocity proportioned to
that of the air jet, and strikes upon the sheets of glass f,f, which are
carried across and beneath the tube b, b, at about one inch distance from
its lower end by means of a set of caoutchouc belts e, e, (one inch wido
and three inches apart) which move at the rate of about four inches per
minute, so that each part of the glass is exposed to the action of the
sand blast for about fifteen or twenty seconds. After striking the glass
the air and sand rebound therefrom, and passing into the side boxes g, I,
(Fig. 3), are carried into the large settling chamber h, h, where they
lose their velocity, and the sand settles to the bottom, while the air
passing on by the tube i (Fig. 2) returns to the centre of the rotary fan
where it receives a fresh impulse. To diminish the escape of dust and
sand the sides of the boxes g, g, are provided with flap valves of
caoutchouc v, v, which close with a slight elastic pressure upon the glass
passing through. There is a direct opening from the boxes g, g, between
the valves v, v, down into the chamber h, so that the pressure of the
blast holds the sheets of glass down upon the belts e, c. The sand
which settles to the bottom of the chamber
into the sand box c, and is repeatedly used
is raised by the elevator k
until it becomes too fine.

page_text: fine sand such as that last mentioned during a sufficient time to produce
a grinding or cutting of the exposed surfaces, and I have thus engraved
photographic pictures. The finer the sand used, and the less the pressure
of the blast, the finer is the grain of the depolished surface and the
weaker and more delicate may be the texture of the covering substances
used to produce the design.
Numerous processes are known and used in the arts for producing,
printing, or transferring designs on to surfaces, any of these processes by
which a design can be produced or transferred in a sufficiently tough
and resistant medium may be used to prepare a surface for being engraved
by the sand blast. Many natural objects such as plants, leaves, &c.,
which can be fastened flat upon a surface have sufficient strength and
resistance to a blast of fine sand to admit of their outline being thus
engraved. Designs engraved by the sand blast to a sufficient depth
either in relief or in intalgio on a smooth surface, slate or glass, for
example, can be reproduced by known processes of printing. When
wood is subjected to a sand blast of moderate velocity the softer and
more brittle portions are more rapidly and deeply cut away than others,
and the grain or texture of the wood and the hard lines and knots are
thus brought out in relief. When the sand blast at moderate velocities
is directed upon a metallic surface it removes but little of the metal, but
the grains of sand make innumerable small indentations of the surface
and produce a frosted, dull, matted, or dead appearance. By using
suitable stencil plates or covering substances, designs, or devices can
thus be engraved on metallic surfaces.
If desired the sand may be propelled by a current of air produced by
suction or a partial vacuum made in any convenient manner, as by a fan,
or steam jet, or any other known machine, or the sand may be impelled
by a mixed current of steam and air produced by a steam jet in the
ordinary manner.
I have described above several arrangements for projecting the sand
with the requisite velocity by means of jets of steam or air, but I do not
mean to confine myself thereto. Any method or arrangement of jets or.
currents of steam, air, water, or other suitable gas or liquid may be used
by which sufficient velocity can be artificially given to the sand to enable ;
it to cut or grind the object.
Having now set forth the nature of the Invention of " Improvements

page_text: in Cutting, Boring, Grinding, and Pulverizing Stone, and other Hard
Substances," as communicated to me from abroad, and having explained
the manner of carrying the same into effect, I wish it to be understood
that what I claim under the above in part recited Letters Patent is,
the employment for the above-named purposes of sand used as a
projectile to which the requisite velocity has been artificially given
by a jet or current of steam, air, water, or other suitable gas or
liquid.
In witness whereof, I, the said Alfred Vincent Newton, have
hereunto set my hand and seal, the Thirty-first day of January,
in the year of our Lord One thousand eight hundred and
seventy-one.