IMPROVEMENTS IN MACHINERY FOR CUTTING DIAMONDS OR OTHER GEMS
Year: 1873

page_text: LETTERS PATENT to Frederick Curtis, of Boston, in the County of
Suffolk, and State of Massachusetts, United States of America, for
the Invention of "IMPROVEMENTS IN MACHINERY FOR CUTTING DIAMONDS
OR OTHER GEMS." -A communication from Charles Myrick Field,
resident at Boston, in the County of Suffolk, and State of Massa-
chusetts, United States of America.
Sealed the 7th November 1873, and dated the 10th July 1873.

page_text: and have made solemn Declaration that it is a communication to
from Charles Myrick Field, resident at Boston, in the County of Suffolk,
and State of Massachusetts, United States of America.
NOW KNOW YE, that I, the said Frederick Curtis, do hereby declare
the nature of the said Invention, to be as follows:-
Heretofore the reducing or cutting of diamonds has been effected by
hand labor to a great extent, if not entirely, and the purpose of this
machine is to perform this labor more perfectly and at much less
expense than has been before accomplished..
These improvements consist,-
First. Of a primary bed plate or base deposited upon a flat tablet and
susceptible of bodily adjustment in suitable guides (making part of such
tablet) and to and fro of such tablet with respect to a tail stock or
carriage for holding the stone to be cut, and which is located at the
opposite side of the tablet, the said main bed plate being fed backward
and forward by a screw or its equivalent and bearing at its front end an
adjustable tool carrier or stock which carries the stone cutting or
reducing tool, the stock being driven backward and forward upon the
main bed by a pitman connected to a crank which makes part of a
horizontal shaft revolving in bearings erected upon the rear end of said
main bed, the pitman being attached to the tool carrier in an adjustable
manner in order that the position or angle of the latter with respect to
the axis of the tail stock arbor may be varied to adapt the machine to
cut the various faces of gems.
Secondly. This Invention consists in the peculiar construction of the
tool carrier of the machine whereby a universal freedom of motion is
obtained, the said construction consisting, first, of a flat plate sliding
upon the main bed in suitable guides; second, of an upright plate or
standard swiveled to the plate in such manner as to be susceptible of
rotary motion in a horizontal plane thereupon; third, of a vertical head
pivoted by a horizontal stud upon the upright standard, and so as to
turn upon its pivot in a vertical path to vary the longitudinal plane of
the tool carrying arbor, both the upright plate and head being provided
with set screws whereby after the proper. angle and adjustment have
been ascertained they are set in position.

page_text: Thirdly. This Invention consists in the peculiar construction of the
tail stock or carriage which holds the diamond or other stone while
being cut, the same consisting of a flat bed plate disposed upon the top
of the tablet of the machine in suitable guides, and susceptible of sliding
movements to and fro with respect to the tool carrier in order to vary
the distance between the spindle or arbors of the two, and adjust the
machine to cut gems of different sizes, or to accomodate the position in
which the gem or the cutting tool may be set in its holder; and this
third portion of this Invention consists further in an upright standard
swivelled to the top of such bed plate and bearing upon its front face
a vertical plate similar to that of the tool carrier before mentioned and
for the same purpose, viz., that of varying the horizontal longitudinal
position of the diamond holding arbor with respect to the arbor of the
tool carrier, the said stock or carriage thus constituted being varied in
position upon the tablet of the machine by a screw or its equivalent, and
provided with a clamp screw to fix its position when obtained.
Like the tool carrier the last named carriage has a vertical plate
pivoted to it to vary its horizontal adjustment, while still further the
vertical plate is fed up and down upon the standard by a feed screw in order
that the axes of the two arbors may be brought to a common horizontal
plane or raised or lowered with respect to each other, this latter adjust-
ment of the said plate being part of a general purpose of the machine to
obtain a universal variable motion of the diamond, or of the tool which
cuts it in order that any face may be cut upon said diamond.
The Drawings accompanying this Specification represent in Figure 1
a vertical section of this machine taken through the main bed or base
plate and its adjusting screw.
Figure 2 is a vertical section through the said main bed or base plate
and the tool holder or carrier to be explained.
Figure 3 is a vertical section of the tool holder or carrier.
Figure 4 is a section of the stone holding carriage.
And, Figure 5 a general plan of the machine.
In the above named Drawings A represents a flat rectangular table or
tablet supported on suitable standards or legs whereby it is maintained
in a horizontal position. A¹ represents a flat rectangular oblong plate
which is termed the main or working bed plate, this plate being placed
Figure 4 is a section of the stone holding carriage.
And, Figure 5 a general plan of the machine.
In the above named Drawings A represents a flat rectangular table or
tablet supported on suitable standards or legs whereby it is maintained
in a horizontal position. A represents a flat rectangular oblong plate
which is termed the main or working bed plate, this plate being placed

page_text: upon the top of the tablet A and extending preferably from front to
rear thereof, and also capable of sliding movements in the direction
of its shortest plane upon the tablet, it being guided in its working path
thereupon by suitable guides or ways a, a, and provided with a feed or
adjusting screw B¹ by which its position upon the tablet may be varied
in order to advance the tool carrier toward the diamond holding carriage
or arbor, or vice versa.
The driving shaft of the machine is a horizontal one, and is shown
at B as revolving in uprights C, C, erected upon the right rear corner
of the tablet A. Upon the inner end of the shaft B is affixed a crank or
crank wheel D, to the wrist of which is pivoted the rear end of a
pitman E, the opposite end of such pitman being pivoted to a post F
erected upon the rear end of a horizontal flat plate G disposed upon the
top of the bed plate A¹ at the right front corner of the latter, and sliding
in dovetailed or other guides or ways, making part of such plate A¹, the
said post being applied to the plate in an adjustable manner, as repre-
sented, in order to vary the line of coincidence of the two arbors of the
machine to be herein-after described.
The revolution of the crank wheel imparts alternating or reciprocating
movements to the plate G upon the main plate A¹. Upon the top of the
plate G and at about its centre is disposed an upright L shaped plate or
standard H, and this standard is pivoted to the plate G by a vertical
pivot I, by which rotary motion of the standard and its arbor or spindle
is permitted upon said plate Ġ, the standard being confined to the plate
in any desired position or angle by a clamp screw J, as shown in
Figure 3 of the Drawings. To the outer or front face of the standard H
is pivoted by a horizontal journal K. a sectoral plate or head L, said head
being susceptible by means of the pivot of a swiveling movement in the
arc of a circle upon the standard, and of being set in any desired or given
position thereupon by a clamp screw M. Upon the upper part of the head L
is formed bearings N, N, and within these bearings is mounted a horizontal
arbor or spindle O, such spindle being the support of the cutting tool.
This cutting tool is in practice a diamond of inferior grade, and is
secured in a collet P whose shank enters a socket created in the end of
the spindle, the diamond being secured within or to the collet by cement
or solder, or by any of the methods now employed to hold diamonds in
hand tools.

page_text: The "tail stock" of the machine or the carriage which supports the
gem to be cut is similar in general construction to the tool carrier
herein-before described, except that it has no alternating motion and is
disposed directly upon the tablet A in lieu of upon the main bed plate A³,
and is changed in position upon such tablet, and toward or away from the
tool carrier by a feed or adjusting screw Q, arranged as shown in
Figure 5 of the Drawings.
Another difference also exists in that the "tail stock" is susceptible
of vertical adjustment by extending its horizontal pivot through a boss
or arm Ⓡ extending rearward from the upright or L shaped standard H,
and screwing through this boss a vertical screw S, the upper part of
which is swiveled within a shelf T departing from the top of the said
standard H.
In lieu of the feed screw B¹ for adjusting the position of the main bed
plate A¹ a lever or its equivalent may be employed, by which the move-
ments of the said bed plate may be effected in much less time than
could be done with a screw. As the tool borne by its carrier moves in
a reciprocating path past a diamond held in or upon the arbor of the
tail stock, it acts upon the diamond with abrasive effect similar to the
same operation by hand labor, but much more rapidly, and is enabled
to reduce a diamond or other stone to its finished form with the
mathematical exactness and finish always resulting from mechanical
means, as distinguished from the results of hand labor. By this arrange-
ment of parts great range and freedom of motion is obtained for the tool
carrier and diamond holder which enables me to instantly and easily
present the diamond to the tool, or cause the tool to act upon the
diamond at any desired angle, which is a matter of great importance in
cutting many faced stones.
The only skilled labor requisite in the operation of this machine is to
apply the diamond to be cut to its supporting arbor, and adjusting its
position to the tool. This being done women or inexperienced persons
can tend the machine while it is reducing the face thus determined, as
no calculation or judgment is involved. As one person of experience
can apply and adjust the diamonds to a number of machines, and as the
cutting of the face is accomplished by the machine in much less time
than by hand, it will be seen that a great economy is effected.
The precise arrangement of the elements of this machine is not

page_text: confined as herein shown, or the construction of such elements indi-
vidually, as these may be varied to a considerable extent without
departing from the character or novelty of this Invention, as for instance
the peculiar variable motions of the tool holder or carrier, and of the
diamond holding carriage or arbor may be transposed from one to the
other, or the tool may be stationary and the diamond reciprocate.
Having described the nature of this Invention, and the manner in
which the same is to be performed, I declare that what I claim as
my Invention to be protected by the herein-before in part recited
Letters Patent is, the herein described machine as a whole or in parts,
or as a principle, with any changes, modifications, or additions, whereby
substantially the same result is produced.