IMPROVE- IN APPARATUS FOR TRAINING, LEVELLING, AND DRESSING MILL- STONES
Year: 1868

page_text: LETTERS PATENT to Robert Young, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVE-
IN APPARATUS FOR TRAINING, LEVELLING, AND DRESSING MILL-
STONES."
PROVISIONAL SPECIFICATION left by the said Robert Young at the
Office of the Commissioners of Patents, with his Petition, on the
12th February 1868.
I, ROBERT YOUNG, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR TRAINING, LEVELLING, AND DRESSING
MILLSTONES," to be as follows, that is to say :-
This Invention comprises improvements relating to framing to be
applied to a millstone, with an adjustable swivelling guide or holder,
and a sliding arm for carrying instruments or tools for training (or
testing the level of), for levelling, and for dressing the surface of the
stone. The Invention also comprises various improved arrangements of
dressing tools and their actuating details for operating with diamonds
or other hard stones or with steel cutters.

page_text: The improved framing consists of a number of arched arms springing
from a flat segmental ring accurately turned to rest upon the surface of
the stone, by preference at its circumference. The arms unite in a
central boss bored to receive a vertical tubular spindle which has fixed
or formed on its lower end a horizontal holder made with V guides
to receive a sliding arm, which can be adjusted horizontally thereon
by means of a screw spindle. The sliding arm projects horizontally and
at right angles from the guide or holder, and is formed with guide
grooves, to which are adapted the various instruments or tools to be
used with the apparatus. The various parts can be adjusted to suit cither
stones with right-handed roads or grooves or those with left-handed ones.
The tubular spindle with the guide or holder is fixed in any horizontal
angle by means of a pinching screw that acts on a ring placed in a
recess in the frame boss, this ring being connected to the tubular spindle
by a key and groove so as to admit of the spindle moving up or down
whilst preventing its turning. The up-and-down movement is controlled
by a lever acting on a collar on the upper end of the tubular spindle,
the lever being jointed to a spindle with stops adjustable by screws,
whereby the lowest position of any tool carried by the apparatus can be
very nicely regulated, and will not be altered by temporarily. lifting the
apparatus for any purpose. A spindle passes up the centre of the
tubular spindle and serves for centering the apparatus by its bottom end
being entered into a centre socket made for the purpose in the top of
the millstone spindle or in a centre piece put in the eye of the stone.
The upper end of the central spindle passes through an eye in a bracket
fixed to the frame boss, and when the parts are adjusted the spindle is
fixed in the bracket by a pinching screw and helps to support and
stiffen the frame. Any suitable tool can be worked on or fixed to the
arm, and by making a tool or gauge slide àlong it any unevenness in
the lands or grinding surfaces can be detected. The parts marked by
the tool or gauge in this way may be dressed level in any convenient
way. The tool or cutter may be fixed or supported on the arm and be
made to act in various ways. Thus it may be moved by hand along the
guide groove on the arm; or it may be drawn in one direction by hand
and be returned and made to cut by a spring; or it may be attached
to an endless band running on pulleys driven at a suitable speed
so as cut always in one direction. Another way of actuating the tool
is by applying a crank or similar motion to it, such as is used in slotting
or shaping machines; or a crank or its equivalent may be arranged

page_text: to give the tool a short rapid stroke whilst a progressive movement is
separately applied to it at the same time. The improved frame and slide
arm may also be used for carrying a rotating diamond or other cutter
of the kind already in use for dressing millstones. With most of the
ways of working the tools it is preferred to adjust the cutting point to
the face of the stone by raising or lowering the main tubular spindle
by means of the lever and screw spindle herein-before referred to. When
a diamond is used it is preferred to fix it in the holder by causing the
cutting point to project through an opening in a plate, which opening
is too small for the entire diamond to pass through, whilst the diamond
is held firmly by a screw pressing it behind. Two or more cutters may
be arranged to act together, being placed in linc one behind the other
like the teeth of a saw, or being placed so as to act in separate lines.
In some cases the training arm and the guide or holder may be used
without the frame, the tubular spindle of the holder being set on the
millstone spindle, or on a spindle fixed in the eye of the stone, or on a
spindle fixed in a hurst box, in which box the stone may be adjusted
by means of screws to a level corresponding to that of the training
arm.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Young in the Great Seal Patent Office
ou the 12th August 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
YOUNG, of Glasgow, in the County of Lanark, North Britain, Engincer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of February, in th
year of our Lord One thousand cight hundred and sixty-cight, in the
thirty-first year of Her reign, did for Herself, Her heirs and successors,
give and grant unto me, the said Robert Young, Her special licence
that I, the said Robert Young, my executors, administrators, and assigns,
or such others as I, the said Robert Young, 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

page_text: United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR
TRAINING, LEVELLING, AND DRESSING MILLSTONES," upon the condition
(amongst others) that I, the said Robert Young, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascer
tain 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 Robert Young, do hereby declare
the nature of my said Invention, and in what manner. the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accom-
panying Drawings, that is to say :-
My said Invention comprises improvements relating to framing to
be applied to a millstone with an adjustable swivelling or fixed guide
or holder and a shifting arm for carrying instruments or tools for
training (or testing the level of), for levelling, and for dressing the
surface of the stone. My Invention also comprises various improved
arrangements of dressing tools and their actuating details for operating
with diamonds or similar hard stones.
The kind of "dressing" process for which the improved apparatus
is designed is that in which a suitable grinding surface is produced
on the lands of the millstone face by forming thereon a series of
minute grooves parallel to each other by giving a diamond or similar
hard stone a simple rectilinear motion along the surface, the diamond
being held so as to present a suitable cutting angle.
And in order that my said Invention and the manner of performing
the same may be properly understood I have hereunto appended three
Sheets of explanatory Drawings, to be herein-after referred to, and
representing various modifications of apparatus with my improvements.
The same reference numerals and letters are used for marking the
same or like parts in all the Figures.
One modification of my improved apparatus is shown upon Sheet 1,
Figure 1 being a plan, Figure 2. a front elevation, partly in section,
,and Figure 3 a vertical section as at right angles to Figure 2;

page_text: Figures 4 and 5 are a vertical section and an elevation, showing a
modification of tool or diamond holder slightly differing from that
shown in Figures 2 and 3:
.
My improved framing consists of a number of arched arms 1 springing
from a segmental ring 2, accurately turned flat on its under side to
rest upon the surface of the stone 3, by preference at its circum-
ference. The arms 1 unite in a central boss 4 bored to receive a
vertical tubular spindle 5, which has fixed or formed on its lower
end a horizontal arni holder 6, made with V guides to receive a shifting
arm 7, which can be adjusted horizontally thereon by means of a screw
spindle 8. The shifting arm 7 projects horizontally and at right
angles from the guide or aim holder 6, and is itself formed with
V guides, to which are adapted the various instruments or tools to be
used with the apparatus. The arm holder 6 extends on both sides
of its tubular spindle 5, and the shifting arm 7 can be adjusted to
suit either stones with right-handed roads or grooves or those with
left-handed ones. The tubular spindle 5, with the arm holder 6, is
fixed in any required horizontal angle by means of a pinching screw 9
that acts through a small block on a ring 10 placed in tlie tubular
frame boss 4, this ring being connected to the tubular spindle 5 by
a key and groove, so as to admit of the spindle moving up or down
whilst preventing its turning. The up-and-down movement is controlled
by a lever 11, centred on the top of the frame boss 4, and which
is connected by links 12 and pins passing through slots in the boss
to a ring 13, which bears up against a collar 14 fixed on the tubular
spindle 5. The outer end of the lover 11 has jointed to it a short
piece 15, into the bottom end of which there is screwed a spindle 16;
having on it a hand wheel for adjusting it by. The lower end of the
adjustment spindle 16 is passed through a hole in one of the framó
arms 1; and has a nut screwed on its bottom end to limit the upward
movement of the spindle, whilst a collar on it above the ärm limits
its downward movement. A forked lever 17, centred on a stud fixed
in the franie aim 1, is arranged to act on the collar on the adjustment
spindle 16, and on being depressed causes the elevation of the tubular
spindle 5 and parts carried thereby. The lowest position of any tool
carried by the apparatus can be very nicely regulated by screwing
the adjustment spindle 16 when the lever 17 is frce, and will not
afterwards be altered by temporarily lifting the apparatus by means

page_text: of that lover. A spindle 18 passes up the centre of the tubular
spindle 5, and serves for centering the apparatus by its bottom end
being entered into a centre socket made for the purpose in the top
of the millstone spindle 19 or in a centre piece put in the eye of the
stone. The upper end of the central spindle 18 passes through an
eye in a bracket 20 fixed to or formed on the top of the frame boss 4,
and when the parts are adjusted the spindle 18 is fixed in the bracket
by a pinching screw 21, and helps to support and stiffen the frame.
The hand lever 17 is used for shifting the arm 7 along its holder 6,
between cach double (or forward and backward) stroke of the tool along
the arm 7, so that the rectilinear cuts along the face of the stone may
be made at the required distance apart. A spindle 22, carried by a
bracket 23 fixed to one of the frame arms 1, has on one end a short
lever with a pin inserted in a slot in the hand lever 17, whilst on
its other end it has a lever, connected by a link 24 to a feed lever
and catch 25 acting on a feed wheel 26 on the end of the screw
spindle 8, which shifts the arm 7.
Before describing the tool or diamond holders shown on Sheet 1 of
the accompanying Drawings I will first describe the modifications of
the frame and other parts for carrying the tools, which are shown on
Sheets 2 and 3.
Figures 6 and 7, on Sheet 2, are a plan and side elevation of a second
modification of apparatus which differs from that herein-before described
in being somewhat simplified by the omission of the tubular spindle 5
and parts connected therewith for raising the arm holder 6, this holder
being fixed to the boss 4 and two of the arms 1 of the frame. The
entire frame has in this case to be adjusted in the proper positions for
dressing each sector of the stone's surface in succession. The boss 4 is
made hollow to go over the head of the millstone spindle 19, and an
adjustable spindle 18 is used for centering the frame, as in the first
modification. There are feed levers 25 with their catches and feed
wheels 26 on both ends of the screw spindle 8, and these feed levers
are connected by a square rod 27, on which there is a handle 28 that
can be shifted along the rod so as to be put in the most convenient
position for the operator.
Figures 10 and 11, on Sheet 2, are a front and a side elevation, both
partly in section, of a third modification of the apparatus which is
arranged for actuating the tool by power, and which is also shown as

page_text: carried by a centre piece 29, set and adjusted in the eye of the stone 3.
The centre piece 29 is formed with a flange to rest on the edge of the
stone round the eye, and it is held down by bolts 30, screwed into a
plate 31 below, whilst it is centred by means of three equidistant radial
screws, of which two 32 are shown. The boss of the centre picce is
bored to receive a tubular spindle-5 formed on the arm holder 6, and
this spindle is held down by a bolt 33 screwed into a plate 34, bearing
up against the under side of the boss. The arm holder 6 has fixed or
formed on it at the ends two brackets 35, which have bearings for and
carry a horizontal shaft 36, having on it fast and loose pulleys 37 to
receive a driving belt from an overhead shaft. The shaft 36 is formed
with a longitudinal groove and passes through an eye formed for it in
the shifting arm 7, and it carries and actuates an eccentric 38, which
slides along it when the arm is shifted. The strap 39 of the eccentric 38
acts on a curved lever 10, which is fast on a short spindle carried in an
cyc formed in the arm 7, and having fast on its other end a lever 41,
which is connected by a link 42 to the tool holder a. With these
arrangements the rotation of the eccentric 38 causes the tool holder to
move backwards and forwards along the V guides of the arm 7. To allow
of varying the length of stroke the eccentric strap 39 is not jointed.
directly to the curved lever 40, but to a curved rack fitted to slide in
a slot formed in the lever, and this rack is in gear with a pinion fast
on a spindle passing through the spindle on which the curved lever 40
is fixed. The pinion spindle has a hand wheel 43 on the further end
of it, and by turning this the joint of the cccentric strap can be shifted.
nearer to or further from the centre, whereby the length of stroke given
by the lever 41 will be varied as required. For feeding or shifting the
arm 7 between the strokes there is on one end of the shaft 36 a boss 44.
with a single tooth arranged to act on a star wheel 45, carried on a stud
and in gear with a wheel 26 on the screw spindle 8, and at cach turn.
of the shaft the wheel 45 is turned the distance of a tooth, and causes
a corresponding movement of the arm 7. The wheels 45 and 26 arc of .
course to be changed for different rates of feed.
Figures 12 and 13, on Sheet 3, are elevations at right angles to each
other of a fourth modification, one part of which is designed for being
set on the head of the millstone spindle 19, whilst the other part is
designed for actuating the tool by power by means of an endless band.

page_text: approximately to fit on the head of the millstone spindle 19, and is
accurately adjusted thereon by means of pinching screws. The arm
holder 6 is adjustable vertically by means of a screw spindle 47 being
formed with V flanges at the back, which fit between vertical guides
formed on the boss 46. Brackets 35 are fixed to the ends of the arm
holder 6 to receive a horizontal grooved shaft 36, with its fast and loose
pulleys 37, by which the power is applied. This grooved shaft 36 passes
through and drives a pulley 48 situated close to one side of the shifting
arm 7, and this pulley, as well as another one 49 at the outer end of
the arm, is held between the arm and a plate 50, which is fixed to the
arm by stud bolts. An endless band 51 passes round the pulleys 48;
49, and has the tool holder a attached to it. This tool holder is formed
with angular projecting sliding surfaces, which fit and run in cor-
responding angular grooves made for them in the inner opposite faces
of the arm 7 and plate 50. The cndless band 51 is driven continuously
in one direction, the tool moving along the bottom grooves when acting,
and returning along the top grooves.
Figures 14 and 15, on Sheet 3, are a plan and a vertical section,
showing a fifth modification of my improved apparatus, which is adapted
to a hurst box 52, constructed for receiving the millstone 8 when it is
about to be dressed. The millstone is shown in section in Figure 15;
but is supposed to be removed in Figure 14. The hurst box 52 is simply
a flanged ring with three arms and a centre, and is represented as
mounted on wheels for convenience in moving it about. Three screws
53 are tapped vertically through nuts fixed in the bottom for levelling
the millstone, whilst it is centered by means of three other screws 54,
which are tapped horizontally through the sides of the hurst box: The
centre is formed with a tubular boss 4, which rises up through the eye
of the millstone, and in this boss is set the tubular spindle 5, which is
fixed to the arm holder 6, as in the first modification; but in an inverted
position. Adjustment as to height is effected by means of a central
spindle 16 with a hand wheel on its upper end, and which has its lower
end screwed into a nut 55 resting on a cap 56 fixed to the bottom of
the boss 4. An annular cap 57 is fixed on the top of the tubular
spindle 5, and has a limited movement between two collars on the
adjustment spindle 16, whilst a forked lever 17 centered on a stud fixed
in the top of the tubular spindle 5 beais on the upper collar on the
adjustment spindle 16, and serves for raising the movable parts when

page_text: shuting the arm 7. Any suitable tool can be worked on or fixed to the
arm 7 in any of the modifications of apparatus herein-beforo described,
and by making a tool or gauge slide along the arm set successively in
different positions any unevenness in the lands or grinding surfaces
can be detected. The diamond tool to be used in the actual dressing
operation may be very conveniently employed for the training process,
and the parts marked by the tool or gauge may be dressed level in the
ordinary or any convenient way. There are various ways in which the
tool or cutter may be supported on the arm 7, and in which it may
be made to act. Thus the tool holder a may be moved by hand along
the V guides on the arm; or it may be drawn in one direction by hand
and be returned by a spring. For moving the tool by hand I prefer to
use a crank handle 6 set loose on a pin on the tool holder a, as shown
in Figures 1 to 9. The tool holders shown in these Figures comprise in
cach case a main plate a provided with V flanges at the back to fit
the V guides of the arm 7, and with one or more diamond holders c,
various ways of adjusting which are shown. In Figures 4 and 5 a singlo
diamond holder c is shown as being held against the plate a by a bottom
screw passing through a slot, whilst there is an inclined scrow at the
top by which it can be raised or set obliquely, the middle screw also
serving for setting it more or less obliquely. In Figures 1, 2, 3, 10, 11,
two diamond holders c are shown on each tool holder a, being fitted
in vertical V grooves with adjusting screws. The tool holder shown in
Figures 6 and 7 is shown enlarged to half-size in Figures 8 and 9, and
is fitted with a single diamond holder c, which is in the form of a spindlo
entered through top and bottom flanges on the plate a, and fixed by a
screw nut at the top. The diamond may be fixed in its holder c in
various ways; in Figures 2, 3, 10, and 11 it is shown as held in a curved
plate & fixed to the holder c by screws, A conical hole is bored into
and partly through this plate from the inside so as to form a cavity with
its outer or bottom orifice contracted or too small for the ontire diamond
to pass, whilst a cutting point can project through to a sufficient extent.
A screw is tapped into the diamond holder, so that its head bears against
the diamond, and this screw can be adjusted to bear more or less upon
the diamond when the plate d is screwed into its place. In a modi-
fication shown in Figures 4 and 5, the screw bearing on the back of
the diamond is made accessible from behind in a manner that will be
best understood from the Drawing. I howover prefer to fix the diamond
in its holder c in the manner shown in Figures 8 and 9, in which

page_text: pieces, shaped so as to build together into the form or a sman sona
cylinder, are formed with slight hollows at the meeting angles of their
lower ends, such, hollows combining to form a cup to hold the diamond.
These separate holding pieces are set in a cylindrical socket formed in the
bottom of the diamond holder c, and are compressed by separate screws,
and with this arrangement the diamond can with ease be fixed in the
very best position.
Some of my improved arrangements herein-before described and shown
in Figures 1, 2, 3, 14, 15, were designed to admit of the tool being raised
on the return stroke so as to cut in one direction only. I have however
discovered that when a diamond of a particular kind is used, and when
the tool holder a is suitably arranged, it may be made to cut in both
directions. It may be passed twice, that is forwards and backwards
over cach line, or it may cut when moving backwards the next line
to that cut when it moved forwards, and the arrangements shown in
Figures 6, 7, 10, 11, are adapted for working in this way. The kind of
diamond I prefer to use and find to answer most satisfactorily in practice
is what is ordinarily called the black diamond or carbon, and is
'met with in Brazil, Siberia, and elsewhere in the form of small rough
dark or dull-colored stones. The. action of the tool is further improved
by introducing a layer of rubber or other suitable elastic material into
the tool holder a so as to prevent absolute rigidity. This interposed
elastic layer is shown in solid black in Figures 2, 9, and 10, the plate a
being in Figures 2 and 10 made in two parts to receive it between
them, whilst in Figure 9 it is simply interposed between the bottom
of the plate a and the enlarged bottom of the diamond holder c. The
interposed elastic layer may be introduced with advantage into any of
the arrangements herein-before described, as it tends to avoid the
abrasion of the diamond. In consequence of the arm 7, on which the
tool holder a slides being entirely overhung, it is apt to be slightly
unsteady unless supported, and I have therefore applied in connection
with it a loaded foot 58, as shown in Figures 6 and 7, which rests on the
surface of the millstone, and is easily shifted thereon along with the
arm 7. This loaded foot is fixed to the horizontal flange on the back
of the arm 7 by one or more screws, but a piece of rubber or other
suitable elastic material is interposed, by the greater or less compression
of which the necessary adjustment is effected.

page_text: In using the modifications shown in Figures 1 to 9, the operator takes
hold of the tool holder handle b with the left hand and moves the tool
holder forwards and backwards along the V guides of the arm 7, and
he actuates the lever 17 (Figures 1, 2, 3) or the lever 28 (Figures 6, 7)
with the right hand when the tool is at either the inner or outer end
of its traverse. If preferred however the positions of the parts may be
reversed in order that the operator may work the tool with his right
hand, and the feed motion with his left hand. When the tool holder a
is arranged for carrying two or more diamonds, these may be disposed
in line, one behind the other like the teeth of a saw; or they may be
disposed so as to act in separate lines, that is, so that two or more lines
may be cut at each stroke of the tool, the feed motion being arranged
to correspond; or again, where a deep cut is wanted, the diamonds may
be set in different lines with the feed motion adjusted to shift the arm
the distance of one line only, so that what may be termed the second
diamond will pass along the line cut by the first, and being more
depressed will deepen the cut, and a third diamond following in its
turn may make it still deeper.
In the Provisional Specification lodged with the application for the
hercin-before in part recited Letters Patent I referred to the use of
rotating diamond cutters, to the use of cutters having short rapid strokes
produced by a crank combined with a separate progressive movement,
and to the use of steel cutters; and with reference to such cutters I
would here remark that any of them that is found to answer in practice
may be carried by my improved framing or guides, but I wish it to be
distinctly understood that I make no claim for such tools separately.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details hercin described and delineated,
but that what I believe to be novel and original, and claim as the
Invention secured to me by the hercin-before in part recited Letters
Patent is,
1. The training, levelling, and dressing of millstones by means of
improved combinations of apparatus, substantially such as are herein
described and delineated.
2. The dressing of millstones by means of a diamond or suitable hard
stone to which a simple rectilinear motion is imparted, and which is

page_text: supported, adjusted, and guided by improved apparatus, substantially
such as is hercin described and delineated.
3. The fixing of the diamond by adjusting it in a cavity with a
contracted outer orifice through which its cutting angle projects,
substantially as herein described and delineated.
In witness whereof, I, the said Robert Young, have hereunto
set my hand and seal, this Eleventh day of August, in the year
of our Lord One thousand eight hundred and sixty-eight,
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
ROBERT YOUNG. (L.S.)