IMPROVED MACHINERY FOR CUTTING, CARVING, AND ENGRAVING UPON IVORY, WOOD, STONE, METALS, AND OTHER SUBSTANCES
Year: 1867

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, for the Invention of "IMPROVED MACHINERY
FOR CUTTING, CARVING, AND ENGRAVING UPON IVORY, WOOD, STONE, METALS,
AND OTHER SUBSTANCES."-A communication from abroad by Isaac Hall,
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the. Office of the Commissioners of Patents, with his Petition, on the
3rd September 1867.
-I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVED
MACHINERY FOR CUTTING, CARVING, AND ENGRAVING UPON IVORY, WOOD, STONE,
METALS, AND OTHER SUBSTANCES," to be as follows:-
This Invention has for its object to furnish. an improved machine by means
of which any desired design or pattern may be cut, carved, or engraved upon
ivory, wood, stone, metal, or other suitable substance. And it consists in the

page_text: construction, combination, and arrangement of the various parts of the
machine as herein-after more fully described and set forth.
The machine is attached to a table having a frame secured thereto with
holes through its base and top bar for the passage of a pivoted frame having
spindles attached to its top and bottom bars, which pass through the holes in
the top bar and base of the frame so as to pivot it thereto. Upon the upper
end of the spindle is placed the loose driving pulley, to which motion is com-
municated from the power, and also a loose pulley which is rigidly connected
to the driving pulley, or made solid therewith, and by which by means of a
band the motion is transferred to the cutter. The lower end of the spindle
rests upon and is pivoted to a short plate, to the ends of which are attached
the ends of a cord which passes over two pulleys pivoted to the under side of
the table upon opposite sides of the spindle, thence through holes in the ends
of a bar, and upon the central part of which cord is booked a weight. The
hook of this weight is made long so that additional weights may be placed
upon it, and so that the pivoted parts of the machine may be exactly balanced
under all circumstances. If desired a lever and weight or any other suitable
counterpoise may be used to balance the machine. A frame is fitted to slide
back and forth within the frame before referred to, and which when adjusted
is secured in place by set screws, which pass through the top bar of the said
frame and press against the shoe or plate clamping the sliding frame between
the said plate or shoe and the bottom bar of frame first mentioned. The
base or lower horizontal bar of the sliding frame has a scale or division marks
formed upon it for convenience in adjusting the position of the frame, so that
the work may be in the desired proportion to the pattern. The horizontal
bars of the sliding frame project beyond the vertical end bars of said frame at
one or both ends, and between the said projecting ends are pivoted two
swinging frames by means of set screws and binding nuts. The top bars of
these swinging frames when both frames are used are connected to each other
by parallel horizontal bars, so that the said frames may always be parallel
however they may be moved about during the progress of the work. Upon
the ends of the top bars of the swinging frames are formed upwardly pro-
jecting arms, four in number, to the upper ends of which are pivoted loose
pulleys, around which pass the bands from the loose pulley before mentioned,.
and in one arm of each frame upon opposite sides of the machine are formed
cutter holders, the shafts of which pass up through the said arms, and are
rigidly connected to the pulleys. Adjustable arms are also attached to the
top bar of the sliding frame by set screws passing through slots in the bases

page_text: of the said arms and screwing into the said frame, so that the said arms may
be adjusted as required to tighten or slacken the driving bands. To the
upper ends of the adjustable arms are pivoted short horizontal bars, to the
upper sides of which at each end are pivoted pulleys between which the bands
pass. A horizontal bar or arm is also formed upon or rigidly attached to the
lower part of one of the swinging frames before described, having vertical
slots formed in it for the reception of the adjustable tracer, and upon its rear
end or upon both ends is formed a handle or handles by means of which the
tracer is moved over the pattern. There is also a frame or holder which is
secured in place by a washer and hand nut screwing upon the lower end of a
screw attached to the frame and passing down through a hole in the table,
several holes being formed in said table for this purpose, so that the position
of said holder may be adjusted as required. The pattern is placed upon the
bed plate of the frame or holder, where it is secured in place by sliding blocks
which are adjusted by set screws. When the copy is to be of the same size
as the pattern the block may be placed upon the top plate of the holding
frame, where it is secured in place by the sliding blocks operated by set screws,
as before described. A holder is also secured to the table of the machine
beneath the cutter of the sliding frame, and which is secured in place by a
washer and hand nut screwing upon the end of a screw attached to the said
holder, and passing down through a slot in the table, so that the said holder
may have a lateral. adjustment. The standard of the holder is made in two
parts sliding vertically upon each other, and secured in place when adjusted
by a thumb nut screwing upon a screw attached to one of said parts, and
passing through a slot in the other part. The sliding part of said holder is
moved up and down by a set screw passing up through the bed plate of the
standard and pressing against the end of the said sliding part; this gives the
holder a vertical adjustment. The tracer is secured in an adjustable. socket.
by a set screw, and which in carving a copy of the exact size of the pattern
should be adjusted directly beneath the cutter. In this case the sliding frame.
before mentioned should be so adjusted that its central point may be exactly.
in line with the pivotting points of the frame. With this adjustment two.
exact copies of the pattern may be carved at the same time.. In case it is
desired to cut a copy larger or smaller than the pattern and in exact. pro-.
portion to it, as, for instance, twice or one half as large, the sliding frame
must be so adjusted that one or other of its ends. may project twice as far from
the pivoting points as the other, but as the cutter and tracer are secured in.
frames which are also pivoted a still farther. adjustment, is necessary to cause

page_text: the tracer and cutter to describe proportional curves of exactly the same form.
This adjustment is effected by moving the tracer outward or inward from the
vertical line of the cutter of the one swinging frame a proper distance. To
enable this to be done with accuracy a scalė or division marks are formed
upon the tracer bar, said scale being so formed that when properly adjusted
the cutter of the other swinging frame, the pivoting points of the sliding
frame, and the tracer may all be in the same straight line. These two adjust-
ments will cause the cutter to describe the curves and outlines of the copy
proportional to and of the same form as those of the pattern, but the pro-
jections and depressions of the copy will be of the same height and depth as
those of the pattern, thus destroying the symmetry of the work. To remedy
this another adjustment is necessary, so that the tracer point in moving over
the pattern may move vertically through a greater or less space than the
cutter in carving the copy, said spaces having the same ratio to each other as
the pattern and desired copy. To accomplish this the tracer is released from
its set screw, so that it may slide freely up and down through its socket, and
to its upper end is pivoted-the end of a slotted bar, the other end of which is
pivoted to the upper end of a rod which passes down through and works
freely up and down in a socket adjustably attached to the tracer bar or arm,
and which has a foot formed upon its lower end which slides over the surface
of the table at the same time that the point of the tracer is passing over the
pattern. The middle part of the slotted bar is pivotted to the upper end of a
rod which passes down through and is adjustably secured to a socket by a set
screw. If the rod is pivoted midway between the tracer and the rod working
in the socket before mentioned as the tracer rises and descends in moving
over the pattern this rod will descend and rise, the said tracer and rod
moving through equal spaces in opposite directions; and if the rod is pivotted
unequally distant from the tracer and rod the said tracer and rod will move
vertically through unequal spaces. This enables the bar to be so adjusted
that the cutter in carving the copy shall move vertically through spaces having
any desired proportion to the spaces through which the tracer moves in
passing over the pattern, so that the copy may be proportional in every
respect to the pattern. If desired the left-hand swinging frame may be
omitted, and the sliding frame be pivoted directly to the frame of the machine
In this case the carving will all be done by the cutter attached to the one
swinging frame, and the tracer will necessarily be placed in the same vertica
line with the said cutter, so that the copies must all be of the same size as the
patterns. It frequently happens that the raised parts of the work require t

page_text: be undercut, to accomplish this, as the cutter and tracer work in a vertical
position a modification of the holder. is necessary, so that the pattern and
work may be set and held at any desired inclination. This is done by pivoting
the bed plates at the centres of their ends to the frame that supports them by
set screws or centres. The ends of the bed plates are connected by pivoted
bars, so that the said bed plates may always be exactly-parallel at whatever
inclination they may be set. The centres revolve in a suitable framework.
To the inner end of the upper centre is attached a dog connected with an
arm attached to the upper bed plate, so that the inclination of the bed plates
may be changed or adjusted by operating the centres. The centres are
secured in place. when adjusted by a set screw, which passes in through the
framework in which the centres revolve, and presses a plug against the
journal of the upper centre. The upper and lower centres are made to
move together by a band passing around pulleys of exactly the same size
attached to the two centres. This belt is only needed when the bed plates
have been removed and the work and pattern are to be attached directly to
the centres; an index is also rigidly attached to the frame of the holder,
which points to a dial attached to the outer end of one of the centres, so that
the holder plates or pattern and work may be conveniently adjusted to the
desired position. The index and dial are only needed when two swinging
frames are used to enable the operator to adjust the work in both holders
in the same relative position as the pattern. When the work to be done
is of such a. character that it requires to be carved upon all sides the bed
plates may be removed, and the pattern and block attached directly to the
centres. By one arrangement only one end of the pattern and block require
to be supported, while by another arrangement both ends require to be
supported. When the work is of such character as to require the bed plates,
but cannot be held between the holder plates, I use the chuck, in which is
a circular plate having a shoulder formed around its edge, and to the face of
which the work is secured by screws, bolts, clamps, or other convenient
means. The plate is pivoted at its centre to the centre of another plate,
which when the chuck is in use is clamped between the holder plates. Upon
one end of this a plate is formed, an ear having a hole through it for the
passage of a bolt, the head of which overlaps the shoulder formed upon the
edge of the circular plate, so as to clamp them securely together in what-.
ever position the circular plate may be set or adjusted. A scale or division
marks should be formed upon this plate, and an index mark or finger
formed upon or attached to the lower plate for convenience in adjusting

page_text: 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 2nd March 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of September, in the year of our Lord One
thousand eight hundred and sixty-seven, 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 "IMPROVED MACHINERY FOR CUTTING, CARVING, AND ENGRAVING
UPON IVORY, WOOD, STONE, METALS, AND OTHER SUBSTANCES," (a communication
to me from abroad by Isaac Hall, of New York City, in the United States
of America, 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 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 the 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 thercon (that is
to say) :-
This Invention has for its object to furnish an improved machine by means

page_text: of which any desired design or pattern may. be cut, carved, or engraved upon
ivory, wood, stone, metal; or other suitable substance. And it consists in the
construction, combination, and arrangement of the various parts of the
machine, as herein-after more fully described and set forth.
Figure 1 of the annexed Drawing is a top or plan view of this improved
machine; Figure 2 is a side view of the same; Figure 3 is a side view of. a
simplified form of the same; Figure 4 is a top view of the same; Figure 5 is
a side view of a modification of the holder; Figure 6 is an end view of the
holder plates; Figure 7 is a detail sectional view taken through the line x, x,
Figure 5; Figures 8, 9, 10, 11, and 12 are detail views of a chuck for
holding the work or pattern; Figures 13 and 14 represent different forms of
double centres for holding the work and pattern; Figure 15 is a detail side
view of a modified form of the holder; and Figure 16 is a detail sectional
view of the same taken through the line a, a, Figure 15.
A represents the table to which the machine is attached; B,is a frame
securely attached to the table A, and having holes through its base and top
bar for the passage of the spindles of the pivoted frame; C is a frame having
spindles c¹ and c³ attached to its top and bottom bars, which pass through the
holes in the top bar and base of the frame B, pivoting the frame C to the said
frame B. Upon the upper end of the spindle c¹ is placed the loose driving
pulley D, to which motion is communicated from the power, and also the
loose pulley E which is rigidly connected to the pulley D or made solid there-
with, and which by means of a band F the motion is transferred to the cutter.
The lower end of the spindle crests upon and is pivoted to a short plate A',
to the ends of which are attached the ends of a cord B¹ which passes over two
pulleys C¹ pivoted to the under side of the table A upon opposite sides of the
spindle c, which passes through holes in the ends of the bar D', and upon the
central part of which is hooked the weight E'. The hook of the weight E! is"
made long, so that additional weights F¹ may be placed upon it, so that the
pivoted parts of the machine may be exactly balanced under all circumstances.
If desired a lever and weight or any other suitable counterpoise may be used
to balance the machine. H is a frame which slides back and forth within the
frame C, and which when adjusted is secured in place by the set screws
ht
which pass through the top bar of the frame C, and press against the shoe or
plate h², clamping the frame. H between the said plate or shoe and the bottom
bar of the said frame C. The base or lower horizontai bar of the frame H
has a scale or division marks forined upon it for convenience in adjusting the
position of the frame, so that the work may be in the desired, proportion to
2

page_text: the pattern. The horizontal bars of the frame H project beyond the vertical
end bars of said frame at one or both ends, and between the said projecting
ends are pivoted the swinging frames I and J by means of set screws and
binding nuts, as shown in Figure 2. The top bars of the frames I and J
when both frames are used are connected to each other by the parallel hori-
zontal bars K, so that the said frames may always be parallel however they
may be moved about during the progress of the work. Upon the ends of the
top bars of the frames I and J are formed upwardly projecting arms i³, ²,
,, to the upper ends of which are pivoted loose pulleys L, around which
pass the bands F, and in one arm of each frame upon opposite sides of the
machine are formed cutter holders, the shafts of which pass up through the
said arms and 2, and are rigidly connected to the pulleys L; M are arms
adjustably attached to the top bar of the frame H by set screws passing
through slots in the bases of the said arms and screwing into the said frame,
so that the said arms may be adjusted as required to tighten or slacken the
bands F. To the upper ends of the arms M are pivoted short horizontal
bars m³, to the upper sides of which at each end are pivoted the pulleys N
between which the bands F pass, as shown in Figures 1 and 4. O is a
horizontal bar or arm formed upon or rigidly attached to the lower part of
one of the swinging frames as I. The bar O has vertical slots formed on it,
as shown in Figure 2, for the reception of the adjustable tracer, and upon its
rear end or upon both ends is formed a handle or handles o³, by means of which
the tracer is moved over the pattern. P is a frame or holder which is
secured in place by a washer and hand nut screwing upon the lower end of a
screw attached to the frame P, and passing down through a hole in the
table A, several holes being formed in said table for this purpose, so that the
position of said holder may be adjusted as required. The pattern is placed.
upon the bed plate p¹ of the frame P, where it is secured in place by the sliding
blocks p³, which are adjusted by the set screws p³. When the copy is to be of
the same size as the pattern the block may be placed upon the top plate p¹ of
the frame P, where it is secured in place by the sliding blocks p³ operated
by set screws as before described. R is a holder which is secured to the
table A beneath the cutter of the frame J, and which is secured in place by a
washer and hand nut screwing upon the end of a screw attached to the said
holder R and passing down through a slot in the table A; so that the said
bolder may have a lateral adjustment. The standard of the holder R is made
in two parts sliding vertically upon each other, and secured in place when
adjusted by a thumb nut screwing upon a screw attached to one of said parts

page_text: and passing through a slot in the other part. The sliding part of said holder,
is moved up and down by a set screw ¹ passing up through the bed plate of
the standard and pressing against the end of the said sliding part; this gives;
the holder R a vertical adjustment. S is the tracer, which is secured in the
adjustable socket T by a set screw V, and which in carving a copy of the;
exact size of the pattern should be adjusted directly beneath the cutter. In:
this case the sliding frame H should be so adjusted that its central point may;
be exactly in line with the pivoting points of the frame C; with this adjust-
ment two exact copies of the pattern may be carved at the same time. In;
case it is desired to cut a copy larger or smaller than the pattern, and in exact
proportion to it, as, for instance, twice or one-half as large, the frame H must
be so adjusted that one or the other of its ends may project twice as far from:
the pivoting points as the other; but as the cutter and tracer are secured in
frames which are also pivoted, a still further adjustment is necessary to cause
the tracer and cutter to describe proportional curves of exactly the same form;
this adjustment is effected by moving the tracer outward or inward from the
vertical line of the cutter of the frame I a proper distance. To enable this to
be done with accuracy a scale or division marks are formed upon the bar O,.
said scale being so formed that when properly adjusted the cutter of the frame J,.
the pivoting points of the frame C, H, and the tracer S, may all be in the same:
straight line. These two adjustments will cause the cutter to describe the curves
and outlines of the copy proportional to and of the same form as those of the
pattern, but the projections and depressions of the copy will be of the same
height and depth as those of the pattern, thus destroying the symmetry of the.
work. To remedy this another adjustment is necessary, so that the tracer:
point in moving over the pattern may move vertically through a greater or
less space than the cutter in carving the copy, said spaces having the same
ratio to each other as the pattern and desired copy. To accomplish this the
tracer is released from its set screw, so that it may slide freely up and down
through its socket, and to its upper end is pivoted the end of the slotted bar V:
the other end of which is pivoted to the upper end of a rod W, which passes
down through and works freely up and down in a socket X adjustably attached
to the bar or arm O, and which has a foot formed upon its lower end which
slides over the surface of the table A at the same time, that the point of the
tracer. is passing over the pattern. The middle part of the slotted bar V is
pivoted to the upper end of the rod Y, which passes down through and is
adjustably secured to the socket z by a set screw. If the rod Y is pivoted
midway between the tracer S and the rod W, as the tracer S rises and.

page_text: descends in moving over the pattern the rod W will descend and rise, the said
tracer and rod moving through equal spaces in opposite directions; and if the
rod Y is pivoted unequally distant from the tracer S and rod W the said tracer
and rod will move vertically through unequal spaces. This enables the bar V
to be so adjusted that the cutter in carving the copy shall move vertically
through spaces having any desired proportion to the spaces through which the
tracer moves in passing over the pattern, so that the copy may be proportional
in every respect to the pattern. If desired, the frame J may be omitted, and
the frame pivoted directly to the frame B, as shown in Figures 3 and 4.
In this case the carving will all be done by the cutter attached to the frame L,
.and the tracer will necessarily be placed in the same vertical line with the
said cutter, so that the copies must all be of the same size as the patterns. It
frequently happens that the raised parts of the work require to be undercut ;
to accomplish this as the cutter and. tracer work in a vertical position a
modification of the holder is necessary, so that the pattern and work may be
set and held at any desired inclination. This is done by pivoting the bed
plates p¹ at the centres of their ends to the frame that supports them by set
screws or centres, as shown in Figures 5 and 6. C¹ are pivoted bars con-
necting the ends of the bed plates p¹, so that the said bed plates may always
be exactly parallel at whatever inclination they may be set. The centres H
revolve in a framework, as shown in Figure 5. To the inner end of the upper
centre is attached a dog I¹ connected with an arm attached to the upper bed
plate, so that the inclination of the bed plates may be changed or adjusted by
operating the centres. The centres are secured in place when adjusted by a
set screw, which passes in through the framework in which the centres revolve
and presses a plug against the journal of the upper centre, as shown in
Figure 5. The upper and lower centres are made to move together by a
band J passing around pulleys of exactly the same size attached to the two
centres. The bolt J is only needed when the bed plates have been removed
and the work and pattern are to be attached directly to the centres. K¹ is an
index rigidly attached to the frame of the holder, and which points to a
dial L attached to the outer end of one of the centres, so that the holder
plates or pattern and work may be conveniently adjusted to the desired posi-
tion. The index K¹ and dial L are only needed when two swinging frames
are used to enable the operator to adjust the work in both holders into the
same relative position as the pattern.
When the work to be done is of such a character that it requires to be
carved upon all sides the bed plates p¹ may be removed and the pattern and

page_text: block attached directly to the centres, as shown in Figures 13 and 14,
Figure 13 showing the arrangement when only one end of the pattern- and
block require to be supported, and Figure 14 showing the arrangement when
both ends require to be supported.
When the work is of such character as to require the bed plates p', but
cannot be held between the holder plates p², I use the chuck M represented
in Figures 8, 9, 10, 11, 12, in which m¹ is a circular plate having a shoulder
formed around its edge, and to the face of which the work is secured by screws
bolts, clamps, or other convenient means. The plate m² is pivoted at. its centre
to the centre of the plate m², which is made in the form shown in Figure 10,
and which when the chuck is in use is clamped between the holder plates p².
Upon one end of the plate m² is formed an ear having a hole through it for
the passage of the bolt m³, the head of which overlaps the shoulder formed
upon the edge of the plate m¹, as shown in Figure 12, so as to clamp the
plates m¹ and m² securely together in whatever position the plate m máy be
set or adjusted. A scale or division marks should be formed upon the plate m²,
and an index mark or finger formed upon or attached to the lower plate m², for
convenience in adjusting the work and pattern so that they may always be set
in the same relative positions.
. When the work is of such a character that it is required to be inclined
longitudinally the holder represented in Figures 15 and 16 is used. In this
holder the bars A2 are pivoted at their centres to an arched frame B³, which is
adjustably secured to the table A by a hand nut and washer in the manner
herein-before described. The bars A2 are connected to each other at one end'
by the connecting bar C³, so that in whatever position they may be placed
they may always be parallel with each other. One end or arm of the pivoted
bar A is slotted longitudinally, as shown in Figure 15. D³, are arms adjust-
ably secured to the slotted bars A' by bolts and thumb nuts, so that they can
be moved back and forth upon the slotted bars A2 to adjust their position to
the size of the work being done. To the other ends of the arms D² are
attached the centres E2, by which the work and pattern are held. To arms
Fattached to the other ends of the bars A2 the work and pattern are secured
by dogs or chucks and centres G2 in the manner herein-after described. The
centres G2 have pulleys H2 attached to them, around which passes the band I
so that the pattern and work may be made to revolve together. Upon the
central part of one of the bars A is formed a scale. or.division marks Je, so
that the said bars may be inclined, at any desired angle according to the
requirements of the work. This holder in connection with the holders herein-

page_text: before described enables the work to be undercut at any desired angle and in
any desired direction.
Having described the nature of this Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
berein-before in part recited Letters Patent is,―
1st. I claim the combination of one or more swinging frames I, J, con-
structed substantially as herein shown and described with the pivoted frame H,
as and for the purpose herein set forth.
2ndly. Adjustably attaching the frame H to the pivoting frame C, substan-
tially as herein shown and described, and for the purpose set forth.
3rdly. Adjustably securing the tracer S to the slotted bar or arm O of the
swinging or pivoted frame I, substantially as herein shown and described, and
for the purpose set forth.
4thly. The combination of the slotted bar V, pivoted rod W, and adjustable
pivoting rod Y, with each other, and with the tracer S and slotted bar or arm
O of the swinging frame I, substantially as herein shown and described, and
for the purpose set forth.
5thly. The combination and arrangement of the pulleys L and N, with the
pivoted frames I, J, frame H, and driving pulleys D, E, for the purpose of
keeping the band or bands F taut while operating the cutter. or cutters what-
ever may be the relative positions of the said frames, substantially as herein
shown and described.
6thly. The adjustable holder R, constructed and arranged substantially as
herein shown and described, and for the purpose set forth.
7thly. The holder P formed by rigidly attaching the bed plates p¹, having
holder plates på adjustably connected with them to a supporting framework,
substantially as herein shown and described, and for the purpose set forth.
8thly. Pivoting the ends of the bed plates p¹ to centres, and connecting
them with pivoted bars G¹, substantially as herein shown and described, and
for the purpose set forth.
9thly. Connecting the centres with a band J', substantially as herein shown
and described, and for the purpose set forth.
10thly. The combination of the index K' and dial L' with one of the
centres, substantially as herein shown and described, and for the purpose set
forth.
11thly. The chuck M formed by the combination of the plates m³, m³,
and clamping bolt m³, with each other, substantially as herein shown and
described, and for the purpose set forth.

page_text: 12thly. The combination of the balancing device A, B, C, D, E¹, or its
equivalent with the lower spindle c of the frame C, substantially as herein
shown and described, and for the purpose set forth.
13thly. The holder formed by the combination of the adjustable arched
frame B, pivoted and slotted bars A2, adjustable arms Ds, having centres E
attached to their outer ends, arms F, and centres G³, pivoted connecting
bar C, band I, and pulleys H³, with each other, substantially as herein shown
and described, and for the purpose set forth.
In witness whereof, I, the said Alexander Melville Clark, have here-
unto set my hand and seal, this Second day of March, in the year
of our Lord One thousand eight hundred and sixty-eight.
A. M. CLARK. (L.S.)