IMPROVEMENTS IN MACHINERY AND TOOLS FOR CUTTING SLATE STONE. MARBLE. AND OTHER MINERALS."AL SPFICATION
Year: 1866

page_text: LETTERS PATENT to George Hunter, of Maentwrog, Merionethshire,
and William Fothergill Cooke, of Aberia, near Carnarvon, North
Wales, for the Invention of "IMPROVEMENTS IN MACHINERY AND TOOLS
FOR CUTTING SLATE STONE. MARBLE. AND OTHER MINERALS."
PROVISIONAL SPECIFICATION left by the said George Hunter and
William Fothergill Cooke at the Office of the Commissioners of
Patents, with their Petition, on the 25th August 1866.
We, GEORGE HUNTER, of Maentwrog, Merionethshire, and WILLIAM
FOTHERGILL COOKE, of Aberia, near Carnarvon, North Wales, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN MACHINERY
AND TOOLS FOR CUTTING SLATE, STONE, MARBLE, AND OTHER MINERALS," to be
as follows:-
This Invention has for its object improvements in machinery and tools for
cutting slate, stone, marble, and other minerals. To effect these objects we
employ a machine consisting of a central moveable table, and over it an axis
firmly supported in bearings and furnished with gearing by which it can be
slowly rotated; this gearing may be in duplicate on each side of the moveable
table and the two driven together. The axis, when required to give a vertical"

page_text: face to large stones, should be divided into three parts, the two outer parts
being firmly supported in their respective bearings on each side of the
moveable table, and the centre part capable of being released from between
the parts supported by the bearings and removeable at pleasure. On this
compound axis two disc cutters, each firmly secured to a collar or boss on its
outer side or the side next to the bearings, are made to traverse; these disc
cutters have on their edges sockets or holders to receive cutting tools, which
may be such as are herein-after described. In front of the disc cutters and
below them is the table which by screws or otherwise is made to traverse
slowly in a direction parallel or nearly parallel to the face of the disc
cutters. In order to face the surface of a block of stone, slate, or other
suitable mineral too large to pass under the axis and collar or bosses of the
disc cutters these latter are run outwards on the axis to the junctions of its
supported ends with the centre piece of the axis, which latter is then removed
and the disc cutters are made fast so that their inner surfaces are flush with
the ends of the supported axes, in which state they may be used either singly
or separately to face one or two blocks at a time. The block (supposing only
one to be fixed) is placed on the table and firmly secured to it, except when
the weight is sufficient to render this unnecessary; the table then carries
the block slowly past one of the disc cutters, and the cutting tools thereon by
removing a slice from the face of the block produce a flat surface of a width
equal to the diameter of the disc cutter. Cutting tools may be applied to
the boss or collar at the back of the disc cutter to cut through the rough
slice of stone a clear path for the axis; or such a path may be made by the
breaking away of the rough slice. When it is an object that the block should
not be scratched by the tools as they come round at the back of the axis the
table must travel at a slight inclination to the face of the disc cutter. We
prefer under certain circumstances to give the longitudinal motion to the
table by means of two parallel screws, each with a nut upon it; these nuts
are rigidly connected together, being formed at the two ends of a cross bar
passing from one screw to the other; the screws are driven together so as to
carry the cross bar forward, and it then comes against pins dropped through
holes in the table, and the table is thus propelled. This arrangement allows
of several tables being used with one machine, so that the machine need not
be kept waiting whilst the stone is being adjusted on the table; as soon as
one cut is complete the stone with the table can be run on and another table
with a stone upon it brought to the cutter. The screws are cased in tubes
with longitudinal slots for the passage of the bar, and are thus protected from
grit. When it is desired to produce a moulded surface we replace the

page_text: central part of the axis, and instead of the disc cutter a cutter roller is.
employed and secured to the axis. The contour of the cutter roller is made,
to correspond with the moulding it is desired to produce, and from end to end.
of the cutter roller and around it sockets are formed for cutting tools. The
stone is fixed on the table as in the former case; it is carried underneath the.
cutter roller and so is reduced to the moulded. form required. In a similar
manner a flat surface or face may be produced. The same machine may also,
be employed in order to cut or turn columns or parts of columns, except that
in this case the stone in place of being fixed to the table is mounted upon.
centres thereon at right angles to the direction in which the table travels:,
The stone having been mounted on the centres is first locked so as to prevent
it turning, and the table is made to travel forward, under the cutter, roller,
until it comes vertically beneath it, then the table is stopped and the stone is.
slowly turned on its centres until it has made a complete revolution, when the,
stone is reduced to the form required. If it be desired to produce longitudinal
flutes on the column it may be done in the same machine, the column or a
series of them being turned lengthways of the table and mounted thereon on
other centres; it is locked, in this position, and as the table travels on
under the cutter roller fixed on the axis and armed with appropriate tools a
flute or flutes are cut from end to end of the column, this being done the
column is turned partly round and another flute or flutes formed in a similar
manner.
In order to form grindstones or cylinders of greater or less length wa
employ cutters which are segments of a cylinder with cutting tools at their
upper edge and arranged at the lower end to turn in a ring guide on a table
or base plate, so that a free passage is left through the cutter segments; tho
cutter segments are driven by spur gear on their exterior, and the block of
stone to be cut is lowered down on to the upper ends of the segments until it
bears on the cutting tools, which gradually cut the block away until it is
reduced from top to bottom to a truly cylindrical form, and then it is received
below on to a truck or table for removal. The cutting tools in each case
before described may be such as have heretofore been employed in cutting
stone by machinery, or they may be made of pieces of sheet or bar steel cut
to a rhomboidal form; these are fitted at one end into a socket, and the other
end forms the cutting tooth and is usually bent slightly, to one side or the
other; this tool can be reversed when it becomes worn; or we use a tool
similar to that just described, but doubled upon itself, that is to say, we fold
over a piece of a bar or a strip of steel on to itself and form from its two ends
two cutting teeth side by side, and these by bending the metal are set a short

page_text: distance apart; or we fold over a piece of steel, as above, but make the bend
around a mandril, and the loop so produced we forge out thin and sharpen to
a cutting edge; or we employ a circular disc of steel such as can be con-
veniently produced by punching pieces from a sheet; this is then forged or
brought to a tapering form by pressure or otherwise at its edge all round, and
it is sharpened; when in use, it is clipped in a suitable holder; a triangular
or other recess or projection is made in the disc to facilitate the holding it in
position, and the turning it when it becomes worn so as to offer a fresh cutting
edge. We also employ for cutting slate, stone, marble, and other minerals a
straight blade to which a reciprocating motion is given; this blade has tool
holders mounted upon it at intervals, into which tools such as those above
described are fitted, or the tools may be such as we have heretofore em-
ployed, that is to say, steel bolts with conical heads sharpened on the edges,
or the tools may be of other forms,
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Hunter and William Fothergill Cooke in the Great
Seal Patent Office on the 25th February 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
HUNTER, of Maentwrog, Merionethshire, and WILLIAM FOTHERGILL COOKE,
of Aberia, near Carnarvon, North Wales, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of August, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said George Hunter and William Fothergill Cooke, Her special licence, that
we, the said George Hunter and William Fothergill Cooke, our executors,
administrators, and assigns, or such others as we, the said George Hunter
and William Fothergill Cooke, our 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 MACHINERY AND TOOLS FOR CUTTING SLATE, STONE,
MARBLE, AND OTHER MINERALS," upon the condition (amongst others) that we,
the said George Hunter and William Fothergill Cooke, our executors or
administrators, by an instrument in writing under our or their hands and

page_text: seals, or under the hand and seal of one of us or them, 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 mouths next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Hunter and William
Fothergill Cooke, 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:-
This Invention has for its object improvements in machinery and tools for
cutting slate, stone, marble, and other minerals. To effect these objects we
employ a machine consisting of a central moveable table, and over it an
axis firmly supported in bearings and furnished with gearing by which it can
be slowly rotated. This gearing may be in duplicate on each side of the
moveable table and the two driven together. The axis when required to give
a vertical face to large stones should be divided into three parts, the two outer
parts being firmly supported in their respective bearings on each side of the
moveable table, and the centre part capable of being released from between.
the parts supported by the bearings and removeable at pleasure. On this
compound axis two disc cutters, each firmly secured to a collar or boss on its
outer side or the side next to, the bearings are made to traverse. These disc
cutters have on their edges sockets or holders to receive cutting tools which may
be such as are herein-after described. In front of the disc cutters and below
them is the table which by screws or otherwise is made to traverse slowly in
a direction parallel or nearly parallel to the face of the disc cutters. In
order to face the surface of a block of stone, slate, or other suitable mineral
too large to pass under the axis and collar or bosses of the disc cutters, these
latter are run outwards on the axis to the junctions of its supported ends
with the centre piece of the axis, which latter is then removed and the disc
cutters are made fast so that their inner surfaces are flush with the ends of
the supported axes, in which state they may be used either singly or separately
to face one or two blocks at a time. The block (supposing only one to be
fixed) is placed on the table and firmly secured to it, except when the weight
is sufficient to render this unnecessary; the table then carries the block
slowly past one of the disc cutters and the cutting tools thereon by removing
a slice from the face of the block produce a flat surface of a width equal to
the diameter of the disc cutter. Cutting tools may be applied to the boss
or collar at the back of the disc cutter to cut through the rough slice of stone.
a clear path for the axis, or such a path may be made by the breaking away

page_text: of the rough slice. When it is an object that the block should not be
scratched by the tools as they come round at the back of the axis the table
must travel at a slight inclination to the face of the disc cutter. We prefer
under certain circumstances to give the longitudinal motion to the table by
means of two parallel screws each with a nut upon it; these nuts are rigidly
*connected together, being formed at the two ends of a cross bar passing from
one screw to the other. The screws are driven together so as to carry the
cross bar forward, and it then comes against pins dropped through holes in
'the table and the table is thus propelled. This arrangement allows of several
'tables being used with one machine, so that the machine need not be kept
waiting whilst the stone is being adjusted on the table, as soon as one cut is
complete the stone with the table can be run on and another table with a
stone upon it brought to the cutter. The screws are cased in tubes with
longitudinal slots for the passage of the bar and are thus protected from grit.
When it is desired to produce a moulded surface we replace the central part
of the axis, and instead of the disc cutter a cutter roller is employed and
secured to the axis. The contour of the cutter roller is made to correspond
with the moulding it is desired to produce, and from end to end of the cutter
roller and around it sockets are formed for cutting tools. The stone is fixed
on the table as in the former case it is carried underneath the cutter roller
and so is reduced to the moulded form required. In a similar manner a flat
surface or face may be produced; the same machine may also be employed
in order to cut or turn columns or parts of columns, except that in this case
the stone in place of being fixed to the table is mounted upon centres thereon
at right angles to the direction in which the table travels. The stone having
been mounted on the centres is first locked so as to prevent it turning, and
the table is made to travel forward under the cutter roller until it comes
vertically beneath it, then the table is stopped and the stone is slowly turned
on its centres until it has made a complete revolution, when the stone is
reduced to the form required. If it be desired to produce longitudinal flutes
on the colunin it may be done in the same machine, the column or a series
of them being turned lengthways of the table and mounted thereon on other
centres. It is locked in this position, and as the table travels on under
the cutter roller fixed on the axis and armed with appropriate tools a flute
or flutes are cut from end to end of the column; this being done the column
is turned partly round and another flute or flutes formed in a similar manner.
In order to form grindstones or cylinders of greater or less length, we employ
cutters which are segments of a cylinder with cutting tools at their upper
edge, and arranged at the lower end to turn in a ring guide on a table or

page_text: .
base plate so. that a free passage is left through the cutter segments. The
cutter segments are driven. by spur gear on their exterior, and the block of
stone to be cut is lowered down on to the upper ends of the segments until
it bears on the cutting .tools which gradually cut the block away until it is
reduced from top to bottom to a truly cylindrical form, and then it is received
below on to'a truck or table for removal. The cutting tools in each case
before described may be such as have heretofore been employed in cutting
stone by machinery, or they may be made of pieces of sheet or bar steel cut
to a rhomboidal form; these are fitted at one end into a socket and the other
end forms the cutting tooth, and is usually bent slightly to one side or the
other. This tool can be reversed when it becomes worn; or we use a tool
similar to that just described but doubled upon itself, that is to say, we fold
over a piece of a bar or a strip of steel on to itself and form from its two
ends two cutting teeth, side by side, and these by bending. the metal are set
a short distance apart; or we fold over a piece of steel as above, but make
the bend around a 'mandril, and the loop so produced we forge out thin and
sharpen to a cutting edge; or we employ a circular disc of steel such as can
be conveniently produced by punching pieces from a sheet;, this is then
forged or brought to a tapering form by pressure or otherwise at its edge all
round and it is sharpened. When in use it is clipped in a suitable holder, a
triangular or other recess or projection is made in the disc to facilitate the
holding it in position, and the turning it when it becomes worn so as to offer
a fresh cutting edge. We also employ for cutting slate, stone, marble, and
other minerals a straight blade to which a reciprocating motion is given, this
blade has tool holders mounted upon it at intervals into which tools such as
those above described are fitted, or the tools may be such as we have here-
tofore employed; that is to say, steel bolts with conical heads sharpened on
the edges, or the tools may be of other forms.
In order that our Invention may be fully understood and readily carried
into effect we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figures 1, 2, Sheet 1, are elevations, and Figure 8. is a plan of sawing
machine with a compound axle and three compound saw tables; Figure 4 is
a flat view of saw blade or cutter A mounted with a number of moveable
teeth or cutting tools-A¹, A¹, in their holders; F, F, and F¹ are three com-
pound saw tables. The free axles B', B, carry the main driving wheels in
duplicate E, E. Between the free axles B¹, B¹, can be fixed a moveable
through axle B which can be removed by running back one of the head-
•

page_text: stocks D on its sole plate D¹. The axle B is only removed when the saw
blades A, A, are required to dress or face a stone of greater depth than will
pass under the axle. When so used each of the cutter blades A, A, is shifted
outwards upon the axle B until it is flush with the free end of B³, and there
made fast. The centre axle is then, removed, and the blades may be used
either singly or separately to face one or two blocks at a time. The block of
stone (supposing only-one to be cut) is then made fast to an outer table F
which carries it slowly past one of the cutting blades, which removes a slice
from the face of the block and produces a flat-surface equal to the diameter of
the blade cutting, tools may be applied to the collar of the blade to cut a
clear path for the axis, or the rough slice may be broken away as it
approaches the axis. The headstocks D, D, are fitted about an eighth of an
inch loose on their bed plates D', so that each can be moved so much out of
the true square that the cutting blades may no longer be quite parallel with
the tables, and so prevent the back cut from rubbing the finished face of the
block. When the loose axle B is replaced the headstocks D, D, are again
set square with the tables. E, E¹, are.the driving pulleys; E, pinion driving
wheel E, on the axle of which are the pinions E, Figure 1, driving main
wheels E, Es, which work with the free axles B¹, B. F, F, F, are the
triplicate parts of the compound table. The two outer tables F, F, are both
worked together by the bevel wheels E, G, E, G, driving the feeding
screws G, G, and receiving their motion from the cones Es for feeding, and
by E for running the table back, the required motion being given through
the clutches E. The centre table F is worked through its separate clutch E
and bevil wheels E, G¹ acting upon the feeding screw G¹ in the manner
shown in Figure 8, Sheet 1. F, F, are the holders or slides to steady the
tables. J, J, Figure 8, are brackets for fastening the blocks to the tables,
and also serve as a gauge to adjust the block to the square. The mode of
working the three compound tables is this:-The two outer tables F, F,
work together, and carry a long slab for cross-cutting or squaring the two
ends by one operation. Whilst the long slab is advancing under cutters
another slab which may have been previously cross cut is fixed in its length
along the centre table. When the outer tables with their cross cat slab have
passed the cutters the cutters are readjusted on the axle B for the narrow
slab on the centre table, which is then made to advance upon the cutters.
The outer pair of tables being unloaded are run back for another slab. That
the slabs may clear the empty tables they are made to rest on half-inch or
inch planks, which at the same time lift the slabs up to the cutter tools which
necessarily revolve clear of the tables. Two small slabs may obviously be cut

page_text: simultaneously on the two-outer tables, one cut at. a time to each slab... The
cutter blades and their collars may be shifted either by sliding them on the
axle B or by a rack wheel in the collar working in a rack cut or cast in the
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length of the axle. Figure 5 shows a method of enclosing the feed screws in
an ordinary single table, so as to keep off the cuttings from the screws G, G:
Gare open tubes having an upper ledge to throw off the dust and cuttings;
and an open side to admit the ends of the transverse cross bar H. H* are
pin holes in the transverse bar. which 'receive the ends of the two pins dropped
through the table, or the pins, may be dropped in front of the transverse
bar H; in either case the transverse bar when advanced by the feed
screws G, G, carries with it the table. The transverse bar is fed onward by
the parallel screws by screw nuts, one at each end of the bar H; this arrange-
ment allows of several tables being used with one machine, so that in this form
also the machine need not be kept waiting whilst the stone is being a-ljusted;
as soon as the first cut is complete the first table with the stone is run on,
and another table No. 2 with a stone upon it brought to the cutter. The
first table is either reloaded with a fresh slab and passed under the cutter.
blades of another machine or. swung round by a crane to follow the table.
No. 2 under the first machine with a fresh slab.
Figure 6 is a.cylinder or cylinders mounted with suitable tools for working
a finished surface on slabs or stones by fluting or other style of cut ornamental
work or the like. Figures 7, 8, 9, Sheet 1, represent tools for operating.on
coal, slate, sandstone, or building stone of suitable quality, and Figures 8, 9,
Sheet 2, represent the same tools in their holders of the full working size.
Figure 7 is full size, and shows two ways of fixing the disc cutting tool in its
holder A. The supporting back A³ has a groove cut down -it to admit the
boss on the back of the disc tool to slip down into its place and proper height.
in the holder. The front part of the holder is pressed against a hollow
corresponding to the boss in the front of the disc, either by the lever action
of the screw A5 or by the direct action of the screw A, shown in dotted lines.
The disc tool is shown flat and in section in the Drawing. These disc tools are
conveniently made by the double action of a punch out of steel. The first
action of the punch cuts a cylindrical disc, and makes the-hollow and boss ;
the second action forces the disc into the necessary conical shape with a sharp
cutting edge, leaving nothing more necessary than a careful hardening suitablé.
to the kind of stone to be cut. The disc tool can be turned in the holder till
its edge is worn away all round. Figure 8 is a tool formed out of a cutting
of steel. A in plan is a simple rhomboid; it may be kept flat for a central
cut, or bent slightly to one side or other across the centre, so that it can be

page_text: reversed when it becomes worn, and still fit its holder A' in which it is firmly
gripped by its own spring; or a similar tool of greater length can be doubled
upon itself, and form with its two ends two cutting teeth side by side, and
these by bending the cutting .ends outward are set a short distance apart, as
shown in A and A', and so clear the way for the cutter blade. Figure 9 is
a piece of steel bent round a mandril, and the loop so produced is forged out
thin in a conical form and sharpened to a cutting edge. As is a side view
of this tool in its holder A; A°, the back view; this kind of tool may
varied in shape for ornamental cutting.
be
Sheet 2, Figures 10 and 11 are elevation and plan of a continuous-cutting
machine to be worked with, the cutting blades and tools already described.
The moveable tables are here carried on two endless pitch chains working
round barrels to which the pitch chains are fitted; the moveable tables are
secured to cross bars by hook pins which carry them forward. F are rollers
carrying the transverse bars H³ to which the moveable tables F10 are attached
by the hooked pins J³, which also serve to hold down both table and block of
stone, the nut on the cross piece at the top which rests one end on the strut J'
and the other end. on. the block of stone binding all together. The roller
barrels G which are made to revolve through E either by strap gearing
wheels, or more accurately still, by feed screws, carry with them the pitch
chains F, F.
The rollers F, Figure 12, fit in.the.groove of the cast-iron.frame Fs on the
top and resting on the cross bars, which are also the axles of the rollers,
framed wooden tables F10, F10, ride, forming light carriages for the stone
blocks. Through a piece of iron forming the front of the carriage or wooden
table the hooked pin bolts Ja pass to clip the cross bars H³, and thus when
J's is screwed up perform the part of holding brackets; J2 for further steadiness
may be made as a saddle for the cross bars as well as a book bolt as shown in
dotted lines F. When the slab of rock has passed the cutter blades the
hooked bolt pins J* and bracket strut J' are taken away, and the table with
its cut slab is allowed to pass on over the rollers F, Figure 10, on to a truck
ready to receive it. Whilst the first slab is being cut a second slab on its
distinct table is made fast by hooked pin bolts and brackets to other cross
bars, and so slabs of stone in succession are fed forward to the cutters without
leaving the sawing machine idle.
The train of wheels E³, Figure 1, Sheet 1, and head stocks D, D, with the
axle B and cutting blades A, A, are not represented in the machine given at
Figures 10, 11, Sheet 2, because they may be the same as before described.
For facing and rounding grindstones of small size, say from 15 inches up

page_text: to 3 feet from slabs previously sawn and faced by the saw cutter machine, a
machine may as herein-before described be employed, consisting of cutters
revolving in a horizontal plane and carrying cutting tools on their upper edge.
The cutters being fixed on a 'ring wheel in such manner that their distance
from the axis of the wheel may be increased or diminished, and the ring wheel
being caused to revolve by spur gear on its exterior. With this construction
of machine the slice of stone to be rounded has a hole bored through its
centre, through which a bolt is passed, by which the slice of stone is firmly
fixed to a frame and slowly lowered down until it bears on the cutting tools,
which gradually round the slice into a finished' grindstone; the stone is then
either lifted up or lowered on to a truck below for removal..
+
In carrying out this part of our Invention, we, however, prefer to reverse
this arrangement, that is to say, to cause the stone to revolve in place of the
cutting tools, and for the cutting tools to act on the upper in place of the
under surface of the stone. Such a machine is represented in Figures 13,
14, 15, Sheet 2. Figure 18 is an elevation, Figure 14 a plan; Figure 15 an
end view of the machine. The stone M to be faced and rounded is placed
upon a turn-table L fixed on the top of a carriage or truck'; a hole I* is
bored through the stone exactly in the centre of the turn-table, a pin bolt at
I is then passed through the hole in the stone and through a corresponding
hole in the turn-table central axle L', and the carriage with the turn-table
and stone is run under the machine, Figure 18. Two or more brackets or
grippers J fix the stone laterally on the turn-table, and the bolt L' holds it
down to the same and the carriage itself is firmly fixed centre to centre under
the machine; on the under side of the turn-table is a ring of teeth L³, in
gearing with which the driving pinion G is slipped. Motion is given to G³
by the wheel Go and pinion G' and cone G³. L is a tool holder carried by
the slide saddle N on the feed screw G": The tool holder Lis screwed down
till low enough to cut the stone M; the pulley G is connected by a strap
with pulley G, and the latter gives motion to the feeding screw G". As the
turn-table L slowly turns round the stone M, the tool saddle N gradually feeds
into the centre cutting a horizontal surface on the stone. This operation has
Whilst this is going on the
to be repeated till the stone is sufficiently faced.
segment rounding tools M (which may be the same as those represented.in
Figures 8, 9) in the saddle N¹ are fixed over the stone M, where it is to be
rounded, and the segment cutting tools (facing in the other direction to L)
may be fed down on the stone by the. handle N or feeding gear may be
applied to it. The tool saddle N has no connection with the feed screw G".
G" may at pleasure be fed through the handle G" by hand, the strap-being

page_text: previously thrown off the pulley G. When the stone has been sufficiently
surfaced and the segment cutting tools have cut a groove round the circum-
ference to half the depth of the stone, the stone is turned on the turn-table
and the same operations are repeated till the grindstone or other stone is
finished. It is obvious that round pedestals may be faced in the same way,
and that instead of leaving the circumference flat as in a grindstone, shaping
tools may after the first round cut has been given finish the edges of the pedestal
to any outline required. To round stones of different diameters with this
machine, sets of tool holders of various segments as before described will also
be required, but the facing tool and holder will be the same.
When any of the tools already described are to be mounted on &
straight blade to which a reciprocating motion is given for sawing a
stone or other block the tools are fitted into moveablo holders, of which
Figure 16 is an elevation, and Figure 17 is a plan. For the purpose of
giving the tool clearance so as not to break or wear on the return stroke
the following arrangement is convenient:-The holder A³ works upon a
pin A, the screw As fixes the tool in the holder A³; A shows the position of
the tool when on the return stroke; A³ the position when cutting, and A'
shows the position of every alternate tool when cutting, supposing several to
be mounted on the same straight blade. The tool holder does not play in
its morticed socket parallel with the straight blade but slightly across it
as shown by the oblique mortice A' into which the holder is dropped before
the pin A, Figures 16, 17, have been put in. When the cutters are to cut
each way two tools may be fitted into the same socket back to back,
Figures 18, 19, about three-quarters of an inch a part. The one tool being
set to cut in the forward, the other in the back motion of the blade, the cut
thus made is about one-eighth inch wider than the tool and so gives clearance
for the returning tool which has dropped into the middle of the oblique
mortice As, by the play of the holder. The tools for this purpose need not
be of a disc form, but of any convenient shape especially such as may be
readily shaped by a punch and readily and securely fixed in their holders by
a screw or other suitable means. A straight blade so mounted with tools may
be worked horizontally or vertically, and water used to wash away the dust,
though the mode of cutting both ways has been shown it is generally preferable
to cut in one direction only. The stroke of the blade must be more than
the distance between each alternate tool. It is not necessary that the blade
should move as the stone may traverse and the blade be fixed, bevilled
enlargements are made in the holder, Figure. 16 at A, A, through which
he dust is forced out by the alternating action of the holder A. Figure 20

page_text: shows how cylindrical disc tools without a bevilled edge may be used in a
straight blade where the tool may cut either in one or both ways. The tool is
fixed diagonally so as to offer a scraping edge to the stone, and by the diagonal
form of the mortice if it is to cut both ways it is alternately brought with
its edge against the opposite sides of the cut; if it is only to cut one way,
then the tools are placed alternately to cut right and left, the tools retiring into
the breadth of the blade along their mortice during the back cut. Figure 20
shows No. 2 tool in the retired position, as in Figure 18, No. 1 tool is in
the position to cut to the right and No. S to the left, or the tool 1, 2, may
show the positions for cutting to the right only, and the tool 2, 3, for cutting
to the left only, in each case 2 will be in its retired position.
In witness whereof, we, the said George Hunter and William Fothergill
Cooke, have hereunto set our hands and seals, this Eighteenth day of
February, in the year of our Lord One thousand eight hundred and
sixty-seven
GEO. HUNTER.
(L.B.)
WILL*. FOTHERGILL COOKE. (L.S.)