IMPROVEMENTS IN CUTTING AND DRESSING STONE AND IN APPARATUS THEREFOR
Year: 1883

page_text: LETTERS PATENT to Moses Kellow of Park Quarries Penrhyndeudraeth, in
the County of Merionethshire, Assistant Quarry Manager for an Invention of
IMPROVEMENTS IN CUTTING AND DRESSING STONE AND IN APPARATUS
THEREFOR
PROVISIONAL SPECIFICATION left by the said Moses Kellow at the Office
of the Commissioners of Patents on the 4th January 1883.
MOSES KELLOW, of Park Quarries, Penrhyndeudraeth, in the County [of]
Merionethshire, Assistant Quarry-Manager "IMPROVEMENTS IN CUTTING AND
DRESSING STONE AND IN APPARATUS THEREFOR
"
"
My invention relates more particularly to the treatment of stone of a laminable
nature; such, for instance, as slate. In cutting material of this description it is
the practice to impart to the operating edge of the cutting instrument either a
rectilinear or a curvilinear motion. In the former case, the motion of the tool
corresponds with that commonly employed in a planing or slotting machine where
loss of time is incurred whilst the tool makes its return stroke. In the latter case,
the motion is similar to that of a circular saw; which, although continuous in its
action, is objectionable when applied transversely to the direction of the "cleavage
or plane of least resistance to separation of the material operated in on account of
the loss of power incurred under such circumstances. When a circular saw of the
ordinary type is employed there is the further disadvantage that the metal of which
it is composed must be sufficiently pliable to permit of the teeth being set or bent
laterally with a view to producing a cut sufficiently wide to clear the body of the
saw. This entails the necessity of the metal being softer than would otherwise
be preferred for a cutting tool. My invention is designed to avoid these disad-
vantages and consists in the construction and use of a rotative tool holder carrying
a series of chisel-shaped cutters mounted in its periphery. These cutters may
consist of simple square bars of steel or other hard metal formed and sharpened to
a chisel edge at their outer or protruding ends.
oblique to the radius of the tool holder and point
in the direction they are intended to follow.
They are arranged at an anglo
forwards; that is to say, in the
They are also slightly inclined

page_text: laterally; their outer or cutting ends projecting outwards relatively to the plane
of rotation of the tool holder. The object of this lateral obliquity is to ensure the
cut having a width sufficient to give clearance; but it is obvious that the same
effect might be produced by forming the tool in a special manner towards the
outer portion of its cutting edge. I prefer to arrange the cutters as regards their
lateral set so that they project alternately towards opposite sides of the tool
holder.
In using a rotative cutting apparatus of the character described, I apply it to the
stone in such a manner that the direction of motion of the cutters, when operating,
shall as nearly as practicable coincide with the plane of cleavage of the stone.
Supposing, for example, that the stone be arranged horizontally in respect to its
plane of cleavage and that the plane of rotation of the cutting apparatus be vertical;'
instead of mounting the travelling bed carrying the stone at such a level as to feed
the same slightly above or slightly below the level of the saw spindle, I cause the
bed to travel at such a height relatively thereto that the cutters only operate
during their passage through a small arc of their revolution, this arc occurring
either in the highest or lowest portion of the vertical plane of their motion. In
each of these arcs the direction of movement of the cutters most nearly approaches
the horizontal and therefore most closely coincides with the direction of the
cleavage.
I prefer to make the rotative cutting apparatus of considerable diameter, the
better to obtain approximate coincidence between the plane of cleavage and the
line of motion of the cutters whilst in operation.
By the arrangements described I am enabled to accomplish a continuous cutting
effect by means of tools tempered to an appropriate degree of hardness and applied
approximately in the direction of the cleavage of the stone operated on; by
which means power is economized, time saved and wear of tools and machinery
reduced.
It will be readily perceived that a rotative cutting apparatus of the character
described is applicable, not only for dividing blocks or slabs of stone of a laminable
nature, but for producing grooves in, or dressing the edges or faces of, such blocks
or slabs; it being only necessary to vary the height of the feed table accordingly,
or to adjust the block or slab in position thereon relatively to the course traced by
the revolving cutters.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed-
by the said Moses Kellow in the Great' Seal Patent Office on the 4th July
1883.
MOSES KELLOW, of Park Quarries Penrhyndeudraeth, in the County of
Merionethshire, Assistant Quarry-manager
"IMPROVEMENTS IN CUTTING AND
DRESSING STONE AND IN APPARATUS THEREFOR"
"
My invention relates more particularly to the treatment of stone of a laminable
nature; such, for instance, as slate. In cutting material of this description it is
the practice to impart to the operating edge of the cutting instrument either &
rectilinear or a curvilinear motion. In the former case, the motion of the tool
corresponds with that commonly employed in a planing machine, where loss of
time is incurred whilst the tool makes its return stroke. In the latter case, the
motion is similar to that of a circular saw, which, although continuous in its
action, is objectionable when applied transversely to the direction of the "cleavage
or plane of least resistance to separation of the material operated in, on account of
the loss of power incurred under such circumstances. When a circular saw of the
ordinary type is employed, there is the further disadvantage that the metal of
which it is composed must be sufficiently pliable to permit of the teeth being set
or bent laterally with a view to producing a cut sufficiently wide to clear the body
of the saw.
This entails the necessity of the metal being softer than would other-.
wise be preferred for a cutting tool. My invention is designed to avoid these
disadvantages, and consists in the construction and use of a rotative tool holder,
carrying a series of chisel-shaped cutters mounted in its periphery. These cutters
may consist of simple square bars of steel or other hard metal formed and
sharpened to a chisel edge at their outer or protruding ends. They are arranged
at an angle oblique to the radius of the tool holder and point forwards; that is to
say, in the direction they are intended to follow. They are also slightly inclined
laterally; their outer or cutting ends projecting outwards relatively to the plane
of rotation of the tool holder. The object of this lateral obliquity is to ensure the
cut having a width sufficient to give clearance; but it is obvious that the same
effect might be produced by forming the tool in a special manner towards the
outer portion of its cutting edge. I prefer to arrange the cutters as regards their
lateral set, so that they project alternately towards opposite sides of the tool
holder.
In using a rotative cutting apparatus of the character described, I apply it to
the stone in such a manner that the direction of motion of the cutters, when
operating, shall as nearly as practicable coincide with the plane of cleavage of the
stone. Supposing, for example, that the stone be arranged horizontally in respect
to its plane of cleavage and that the plane of rotation of the cutting apparatus be
vertical, instead of mounting the travelling bed carrying [the stone at such a
level as to feed the same slightly above or slightly below the level of the saw
spindle, I cause the bed to travel at such a height relatively thereto that the
cutters only operate during their passage through a small are of their revolution,.
this are occurring either in the highest or lowest portion of the vertical plane of
their motion. In each of these arcs the direction of movement of the cutters most
nearly approaches the horizontal and therefore most closely coincides with the
direction of the cleavage.
I prefer to make the rotative cutting apparatus of considerable diameter the
better to obtain approximate coincidence between the plane of cleavage and the.
line of motion of the cutters whilst in operation.

page_text: By the arrangements described, I am enabled to accomplish a continuous cutting
effect by means of tools tempered to an appropriate degree of hardness and applied
approximately in the direction of the cleavage of the stone operated on; by
which means power is economised time saved and wear of tools and machinery
reduced.
It will be readily perceived that a rotative cutting apparatus of the character
described is applicable, not only for dividing blocks or slabs of stone of a laminable
nature, but for producing grooves in, or dressing the edges or faces of, such blocks
or slabs; it being only necessary to vary the height of the feed table accordingly or
to adjust the block or slab in position thereon relatively to the course traced by
DESCRIPTION of the DRAWINGS.
Figures 1 and shew in face and edge view respectively my improved rotative
tool holder and the manner in which it is applied to the material to be operated
on. Figure 3 represents, to an enlarged scale, a portion of the periphery of the
said holder with the cutters mounted therein. Figures 4 and 5 are sectional views
on the lines Y Y, Z Z. The same letters of reference indicate corresponding parts
in all the figures.
I form the body of the tool holder by preference in three parts; that is to say,
two external discs a a¹ and a central disc b, the latter being formed with inclined
slots for the reception of the cutters c and their fastening appurtenances. Or the
central portion b may be an annulus concentric with the discs a a¹ and carried by
them. The tool holder is secured to a central shaft d by means of which a rotative
motion is imparted in the direction of the curved arrow (Figure 1). e is a bed on
which the material to be operated on is arranged; and this bed is caused to
partake of a slow horizontal motion in the direction of the straight arrow
(Figure 1) by means of any suitable mechanism commonly employed for such a
purpose; as, for instance, in planing machines. The cutters c have a slight lateral
inclination alternately towards the opposite faces of the tool holder so as to ensure
the cut having sufficient width to give clearance.
The cutters c are secured in the slots in the central disc or annulus 6 by means
b
of adjustable taper keys or wedges f; but between such wedges and the cutters I
prefer to interpose packing pieces g. These are arranged in recesses formed for
ibeir reception in the body of the disc b as shewn in Figure 3ª such recesses
preventing the packing pieces moving longitudinally. In order however to prevent
tlieir escaping from the recesses on the withdrawal of the cutters I apply pins h h
mounted in the disc or annulus b and passing through slots in the packing pieces g:
The wedges are provided with a screwed tang fitted with a nut i, the face of which
bears against a suitably formed shoulder on the tool holder and the back of which
bears against a similar shoulder on the disc a or a¹, as the case may be. The nut i
being thus retained in position laterally it is obvious that when the same is turned
on its axis, the wedge will be moved either forwards to secure the cutter c or
backwards to release same.
It will be observed in reference to Figure 1 that the direction of movement of
the cutters whilst in operation is approximately horizontal and closely coincides
with the direction of the cleavage of the slate or other stone of a laminable nature
under treatment; the length of cut being at the same time considerable. Further,
that the circular direction of the cutters' motion in conjunction with the horizontal
advance of the material as it is fed forward results in a variation in the depth of
the cut or "bito" of the cutters; the minimum bite being applied to that portion
of the material where the substance is thin and where it would, unless operated
upon gently, be liable to injury. Moreover, that the direction of the cut, after
commencing horizontally, tends slightly downwards towards the surface of the
material in contact with the bed on which it rests; the tendency for portions of
that surface to break away being thus obviated. Further, the cutters, being

page_text: independent and detachable from the tool holder, may be tempered to an appropriate
degree of hardness and readily sharpened.
Having thus described the nature of my invention and the manner of carrying
the same into effect, I would have it understood that I claim :-
First, The use, for cutting or dressing slate or other stone of a laminable nature,
of a rotative tool, provided with adjustable and detachable cutters and arranged in
such a manner in relation to the material under treatment that the cutters operate
in a direction closely coinciding with that of the cleavage, substantially as
described.
Secondly, The construction of circular tool holder furnished circumferentially
with removable chisel-shaped cutters mounted obliquely and secured by means of
adjustable fastenings, substantially as, and for the purposes described.
In witness whereof I the said Moses Kellow have hereunto set my hand and
seal this third day of July in the year of our Lord One thousand eight
hundred and eighty three.