IMPROVEMENTS IN APPARATUS FOR DRESSING MILLSTONES
Year: 1868

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery
Lane, in the County of Middlesex, Patent Agent, for the Invention
of "IMPROVEMENTS IN APPARATUS FOR DRESSING MILLSTONES." - A
communication from abroad by Ambroise Dubois, Mechanical
Engineer, and Jean Joseph Pouilley, Miller, both of 13, Boulevart
St. Martin, Paris.
Sealed the 10th November 1868, and dated the 26th May 1868.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 26th May 1868.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN APPARATUS FOR DRESSING MILL-
STONES," to be as follows:-
This Invention relates to apparatus for dressing millstones. It is
well known that the dressing operation consists in forming radial
grooves at a certain inclination over the whole working surface of the

page_text: stone so that during its rotation the radial cuts form varying angles
which act in the manner of shears.
Hitherto these stones have always been dressed by hand with a
hammer made of well tempered cast steel having a cutting edge, the
operation being very carefully performed by experienced hands.
This Invention relates to apparatus to be employed for dressing,
cleaning, or setting millstones at any inclination or in any direction.
These operations are effected by the aid of a diamond cutter which forms
the groove in an expeditious manner without the aid of an experienced
workman. One man may with this machine cut a pair of stones in
four hours which ordinarily requires a whole day. The grooves are
further cut with mathematical precision, the working surface of the
stone alone being operated on without interference with the cells or
cavities, so enabling the grooves or furrows to be increased in number
and more regular in arrangement. This apparatus possesses great
simplicity, and may be readily placed in position for dressing stones
grooved in one or other direction in a much more regular manner
and in a fourth of the time required when using a hammer. The
dressing being effected with a diamond penetrating to a greater or
less extent, and only removing the roughness produced by the grinding
operation the grooves or furrows may be thus made much closer,
while the natural grain of the stone is preserved without leaving any
deep indentations, as with a hammer which hardens and injures the
parts of the stone.
Millstones dressed with the apparatus of this Invention produce a
much softer and lighter bread than usual, the bran is larger and more
easily separated, the flour is also finer and has more body, the grits
are also much whiter and drier, and the result of the grinding is
generally more satisfactory.
This mode of dressing millstones further enables the hand method
to be dispensed with, which is very laborious and prejudicial to the
health.
I have represented in the accompanying Drawings one example of
the mode of carrying out the Invention.
Figure 1 is a plan of the apparatus, and Figure 2 a front elevation;
Figure 3 shows a central vertical section of a running millstone on

page_text: line 1, 2, 3, 4, Figure 1, with the apparatus applied shown in
view; Figure 4 shows a plan of a part herein-after described; and
Figure 5 a section of same on line 5, 6, Figure 4; Figure 6 is a front
view of the cutter carrier; Figure 7, a vertical section; and Figure 8
a horizontal section of same on line 7, 8, Figures 6 and 7. The same
letters refer to similar parts in all the Figures.
a, stone to be dressed, being what is termed the bed stone; on this
is placed the apparatus of this Invention and fixed to the iron centre
pin; if, on the contrary, it is to be applied to the running stone I
insert the pivot a', Figures 3, 4 and 5, into the central opening or
eye and fix the apparatus thereto. b, frame or tripod placed on the
stone in a perfectly horizontal position, which is regulated by the
adjusting screws c bearing on cast-iron feet d, it being fixed either
to the centre pin or to the pivot before mentioned by the aid of
The
screws passing through a socket f cast at the lower part of b.
upper part of the frame b is made perfectly true to receive an adjustable
part 9 carrying an arm h also truly faced, which is capable of being
inclined more or less to the right or left and serves as a guide for
a sliding cutter carrier. The adjustable part g is fixed in the desired
position in the centre of 6 by a hollow cap i fitting on a small socket
and resting on part g, it being held in position by an adjusting screw j..
The end of arm his supported or held in position by a bent
arm provided with a set screw c¹ bearing on foot d. 1, carrier,
transversely to which is mounted a slide m moving on the arm or
guide h. The carrier is provided with a screw of equal length
therewith, terminating in a squared part, on which is fixed a spring
ratchet n operated by a handle o for advancing or withdrawing. the
cutter carrier p. This movement may also be operated automatically
during the longitudinal motion of the carrier. q, disc fixed at one
end of the carrier serving to regulate the motion of the handle; r,
socket fixed to the cutter carrier p, in which is placed the diamond
cutter & in a mounting of silver t held in a clip by means of
screws ; x, spiral steel spring placed in socket r, and bearing on the
upper part of the clip u of the cutter carrier. From this arrangement
it results that when any sufficient resistance is met with the clip at
once recedes and passes over it so as to avoid breaking the diamond
point; a screw y serves to regulate this action as also to limit the
upward motion of the diamond at such time. In this manner whatever

page_text: may be the nequalities of the stones the pressure of spring x will be
always equal and prevent the action of the diamond being arrested.
Instead of using a spiral steel spring, as above described, I may
employ an india-rubber seating or any kind of spring or other means
whereby the cutter carrier may be rendered elastic and adjustable
under a certain pressure. 2, guard fixed to clip u for protecting the
diamond from injury when the machine is not in use.
The action of the apparatus is very simple:-I first commence by
firmly fixing the frame to the centre of one or other stone, and regulate
its horizontal position by means of adjusting screws c; this done I
place the arm h in the desired direction and well over the part to be
dressed, and fix the adjustable part 9 by means of the hollow cap
i and nut j, after which the diamond & is adjusted in height by means
of the screw acting on clip of cutter carrier p; I then take the
handle of slide m and ratchet n in the two hands and impart a
to-and-fro motion to the carrier on arm h, serving as a guide therefor;
the carrier is slid from the edge of the stone to the end of the part
to be redressed, after which it is returned to the starting point;
at this moment the handle o of ratchet n is caused to describe an
arc of a circle for the purpose of advancing carrier and displacing
the diamond & just the distance between any two lines of the dressing,
when the operation is repeated until the whole of the grooving is
entirely reset, and so on for all the others. The diamond & when first
moved cuts a groove parallel with arm and returns in the same
line, which is again grooved by the pressure of the spring a forcing
the cutter downwards. By reason of this rectilinear to-and-fro motion
the diamond is less liable to wear, while a saving of time is also effected.
The radial grooves are cleaned and the stones prepared in a similar
manner, except that diamonds of a larger surface are employed so as
to accelerate the operation; this latter object may also be attained by
providing the carrier / with several cutters working together so as to
form several grooves at a time.
The chief features of the apparatus for dressing millstones herein
described are,-
1st. The ribbed frame with adjusting screws serving to fix the
annaratus in nosition.

page_text: 2ndly. The adjustable head and guide arm capable of being placed
at any desired inclination for dressing millstones with right or left
hand grooves.
3rdly. The arrangement of cutter carrier.
4thly. The socket and clip for holding the diamond cutter arranged
as described and represented in Figures 6, 7 and 8, which is rendered
elastic so as to avoid injury to the cutter.
5thly. The pivot herein-described for fixing the apparatus to the
running stone, it being understood that the form and arrangement
of the parts may be varied without departing from the Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 25th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of May, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her
special licence that I, the said Alexander Melville Clark, my executors,
administrators, and assigns, or such others as I, the said Alexander
Melville Clark, 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 APPARATUS FOR DRESSING MILLSTONES,"
a communication to me from abroad by Ambroise Dubois, Mechanical
Engineer, and Jean Joseph Pouilley, Miller, both of 13, Boulevart
St. Martin, Paris, upon the condition (amongst others) that I, the
said Alexander Melville Clark, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands

page_text: 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 Alexander Melville Clark, do
hereby declare the nature of the said Invention, and in what manner
tlie same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Sheet
of Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say) :-
This Invention relates to apparatus for dressing millstones. It is
well known that the dressing operation consists in grooving the whole
working surface of the stone in different directions, so that during its
rotation the cuts form varying angles which act in the manner of
shears.
Hitherto these stones have usually been dressed by hand with a
hammer made of well tempered cast steel having a cutting edge, the
operation being very carefully performed by experienced hands.
'This Invention relates to 'apparatus to be employed for dressing mill-
stones at any inclination or in any direction. This operation is effected
by the aid of a diamond cutter which forms the groove in an expeditious
manner without the aid of an experienced workman. One man may
with this machine dress a pair of stones in four hours, which operation
ordinarily requires a whole day. The grooves are further cut with
mathematical precision, the working surface of the stone alone being
operated on without interference with the cells or cavities so enabling
the grooves to be increased in number and more regular in arrangement.
This'apparatus possesses great simplicity, and may be readily placed in
position for dressing stones furrowed in one or other direction in a
much more regular manner and in a fourth of the time required when.
using a hammer. The dressing being effected with a diamond pene-
trating to a greater or less extent, the rough uneven surface of the
stone is removed, enabling the grooves to be made much closer while
the natural grain of the stone is preserved without leaving any deep
indentations as with a hammer which hardens and injures those parts
of the stone.

page_text: Invention produces a much'softer and lighter bread than usual, the bran
is larger and more easily separated, the flour is also finer and has more
body, the grits are also much whiter and drier, and the result of the
grinding is generally more satisfactory.
This mode of dressing millstones further enables the hand method to
be dispensed with, which is very laborious and prejudicial to the health.
I have represented in the accompanying Drawings one example of
the mode of carrying out the Invention.
Figure 1 is a plan of the apparatus, and Figure 2 a front elevation;
Figure 3 shows a central vertical section of a running millstone on
line 1, 2, 3, 4, Figure 1, with the apparatus applied shown in side view;
Figure 4 shows a plan of a part hercin-after described, and Figure 5
a section of same on line 5, 6, Figure 4; Figure 6 is a front view of
the cutter carrier; Figure 7 a vertical section, and Figure 8 a horizontal
section of same on line 7, 8, Figures 6 and 7. The same letters refer
to similar parts in all the Figures.
a, stone to be dressed, being what is termed the bedstone; on this is
placed the apparatus of this Invention, and fixed to the iron centre pin
or spindle. If on the contrary it is to be applied to the running stone
I insert the pivot a', Figures 3, 4, and 5, into the central opening or
eye and fix the apparatus thereto. b, frame or tripod placed on the
stone in a perfectly horizontal position, which is regulated by the
adjusting screws c bearing on cast-iron feet d, it being fixed either to
the centre pin or to the pivot before mentioned by the aid of screws
passing through a socket f, cast on the lower part of b. The upper
part of the frame b is made perfectly true to receive an adjustable part g
carrying an arm h also truly faced, which is capable of being inclined
more or less to the right or left and serves as a guide for the sliding
cutter carrier. The adjustable part g is fixed in the desired position in
the centre of 6, by a hollow cap i fitting on a small socket and resting
in part g, it being held in position by an adjusting screw j. The end
of arm h is supported or held in position by a bent arm k, provided
with a set screw c¹ bearing on foot d. 1, carrier, transversely to which
is mounted a slide m moving on the arm or guide h; the carrier / is
provided with a screw of equal length therewith, terminating in a

page_text: squared part on which is fixed a spring ratchet n operated by a handle o
for shifting the position of the cutter carrier p in either direction to
form a series of grooves. This movement may also be operated auto-
matically during the longitudinal motion of the carrier. q, disc fixed
at one end of the carrier serving to regulate the motion of the handle o;
v, socket fixed to the cutter carrier p, in which is placed the diamond
cutter 8 in a mounting of silver t held in a clip u by means of screw ;
x, spiral spring placed in socket r, and bearing on the upper part of
the clip of the cutter carrier. From this arrangement it results that
when any sufficient resistance is met with, the clip at once recedes and
passes over it so as to avoid breaking the diamond point; a screw y
serves to regulate this action, as also to limit the upward motion of the
diamond at such time. In this manner whatever may be the inequalities
of the stones the pressure of spring will be always equal and prevent
the action of the diamond being arrested.
Instead of using a spiral steel spring as above described, I may
employ an india-rubber seating or any kind of spring or other means
whereby the cutter carrier may be rendered elastic and adjustable
under a certain pressure. z, guard fixed to clip u for protecting the
diamond from injury when the machine is not in use.
The action of the apparatus is very simple: -I first commence by
firmly fixing the frame to the centre of one or other stone, and regulate
This done, I
its horizontal position by means of adjusting screws c.
place the arm h in the desired direction and well over the part to be
dressed, and fix the adjustable part g by means of a hollow cap i and
nut j, after which the diamond s is adjusted so as to project more or
I then
less by means of the screw acting on clip r of cutter carrier p.
take the handle o of the slide m with one hand and ratchet u with the
other, and impart a to-and-fro motion to the carrier or arm h serving
as a guide therefor. The carrier is slid from the edge of the stone to
the end of the land or part to be dressed, after which it is returned to
the starting point. At this moment the handle o of ratchet n is caused
to describe an arc of a circle for the purpose of advancing carrier and
displacing the diamond & just the distance between any two lines of
the dressing when the operation is repeated until the whole of the
groove is entirely reset, and so on for all the others. The diamond s
when first moved cuts a groove parallel with arm h, and returns in the

page_text: a
same line, which is again grooved by the pressure of the spring x forcing
the cutter downwards. By reason of this rectilinear to-and-fro motion,
the diamond is less liable to wear while a saving of time is also effected.
The furrows are prepared in a similar manner, except that diamonds of
à larger surface are employed so as to accelerate the operation. This
latter object may also be attained by providing the carrier with several
cutters working together so as to form several grooves at a time. The
apparatus instead of being worked by hand as described may also be
driven by other power by connecting it with a suitable motor.
2ndly. I may dispense with the feet and adjusting screws of the
ribbed frame a, substituting therefor a fixed frame of a single piece
with a perfectly true surface in such manner that the central plate
on which the movable head rests will be always in a perfectly horizontal
position, that is to say, parallel with the surface of the stone to be
dressed. In this manner a level need not be used to determine its
horizontal position.
3rdly. Instead of diamonds other suitable natural or artificial hard
substance may be used as cutters, and I may employ any suitable mode
of mounting the same.
4thly. The arm of the movable head may also be provided with
pivots and slides to permit of its inclination at any angle for making
the furrows and grooves in the stone of curved form.
Having described the nature of this Invention, and the manner of
performing the same, I declare that what I claim as improvements in
apparatus for dressing millstones to be protected by the herein-before in
part recited Letters Patent is,-
1st. The ribbed frame with adjusting screws serving to fix the
apparatus in position.
2ndly. The adjustable head and guide arm capable of being placed
at any desired inclination for dressing millstones with right or left-hand
grooves.
3rdly. The arrangement of cutter carrier.
4thly. The socket and clip for holding the diamond cutter arranged
as described and represented in Figures 6, 7, and 8, which is rendered
elastic so as to avoid injury to the cutter.

page_text: 5thly. The pivot herein described for fixing the apparatus to the
running stone. It being understood that the form and arrangement of
the parts may be varied without departing from the Invention.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-fifth day of Novem-
ber, in the year of our Lord One thousand eight hundred and
sixty-eight.
Witness,
JAMES DAISH,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)