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Патент USA US3027962

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April 3, 1962
3,027,952
W. B. BROOKS
DRILL BIT
Filed July 30, 1958
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FIG. 6
WARREN B. BROOKS
INVENTOR.
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ATTORNEY
April 3, 1962
3,027,952
w. B. BROOKS
DRILL BIT
Filed July 30, 1958
4 Sheets-Sheet 2
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FIG. 7
WARREN B. BROOKS
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IN VENTOR.
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ATTORNEY
April 3, 1962
w. B. BROOKS
3,027,952
DRILL BIT
Filed July 30, 1958
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4 Sheets-Sheet 3
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FIG. 9
WARREN B. BROOKS
INVENTOR.
809%
A T TORNEY
April 3, 1962
w. B. BROOKS
3,027,952
DRILL BIT
Filed. July 30, 1958
4 Sheets-Sheet 4
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FIG. I O
WARREN B. BROOKS
INVENTOR.
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ATTORNEY
"nited States P2111611‘: 3C6
3,027,952
Patented Apr. 3, 1962',
2
1
FIG‘. 5' is a perspective‘ view of a dodecah‘edron form
3,027,952
' of diamond;
DRILL BIT
Warren B. Brooks, Dallas, Tex., assignor, by mesne as
signments, to Socony Mobil Oil Company, Inc., New
York, N.Y., a corporation of New York
Filed July 30, 1958, Ser. No. 751,936
5 Claims. (Cl. 175—329)
FIG. 6 is a top plan view of the dodecahe'dron form
of diamond shown in FIG. 5;
FIG. 7 is an enlarged fragmentary sectional view of
a portion of a bit and a formation being drilled, illus
trating the positioning of an octahedron form. of diamond
in the matrix of a bit in accordance with the invention;
FIG. 8 is a diagrammatic perspective representation
This invention relates to drill bits and relates more par
ticularly to drill bits adapted to penetrate extremely hard 10 of an octahedron diamond set in a drill bit in accord
earth formations such as are encountered while drilling
boreholes during exploration for petroleum oil, gas, and
mineral deposits.
'
Drill bits adapted to penetrate extremely hard earth
ance with the invention, illustrating the position of a sin
gle diamond relative to both the longitudinal axis of the
bit and a radius line drawn from the longitudinal axis
through the diamond;
employ hard inserts in drill bits, such 2E, inserts formed
FIG. 9 is a diagrammatic perspective view of only a
cube face of the diamond of FIG. 8, showing its position
of hardened metal or diamonds.
relative to both the longitudinal axis of a bit and a radius
formations are well-known.
It has been customary to 15
In those bits where di
amonds are used as inserts, the diamonds are embedded
line; and
FIG. 10 is a plan view of the lower portion of a
in a matrix material which is formed around the sides
and lower ends of the bits. The placement of the 20 coring-type drill bit, showing a plurality of diamonds
set in the matrix of a drill bit in accordance with the
diamonds in the matrix has followed varying patterns.
invention.
In some bits the diamonds have been set at random into
Investigation has shown that among the diamonds most
the surface of the matrix with no consideration being
commonly employed in drill bits the internal crystallo
given to special positioning or orientation of the diamonds.
In other hits the diamonds have been placed in the matrix 25 graphic structure of the diamonds is identical even though
their external shapes may differ. The term “internal
in concentric circles which emanate from the center of
crystallographic structure” as used herein refers to the
the bit. Some effort has been made to orient the dia
arrangement of the atoms in a diamond crystal and the
monds in the matrix for the purposes of improving the
chemical bonds which tie the atoms together. The bonds
life of the bit and increasing its cutting efficiency. In
the latter case, most of the diamonds have been positioned 30 between all the atoms of a diamond have equal strength;
however, they are so distributed that there are more
at a particular angle with respect to the surface of the
bonds in certain layers Or directions within a crystal
matrix and sloping in the direction-of rotation of the bit.
than exist in other layers or directions. This unequal
Bits employing random-set diamonds and bits provided
distribution of the bonds between the atoms creates
with diamonds oriented by previously known methods
leave much to be desired with respect to both the depth 35 planes of unequal strength and resistance to abrasion.
With a knowledge of the distribution of the bonds be
of penetration obtainable before replacement is required
tween the atoms within a crystal, it is possible to as—
and the diamond loss incurred per unit of penetration
during drilling.
certain the directions of maximum hardness, that is,
those directions which will be most resistant to abrasion,
It is an object of this invention to provide a drill bit
which employs diamond cutting elements. It is an 40 within the several basic crystal forms used.
Illustrated in FIGS. 1-6 are various single crystal
object of this invention to provide a drill bit which em
forms of diamonds which are the ones most commonly
ploys diamonds which are oriented at uniform predeter
found and employed as cutting elements in drill bits.
mined angles irrespective of the plane of the matrix of
These forms are the cube, FIGS. 1 and 2; the octahedron,
the bit. It is another object of this invention to pro
45 FIGS. 3 and 4; and the dodecahedron, FIGS. 5 and 6.
vide a drill bit in which diamonds are oriented in the
Though they clearly do not resemble each other in ex
matrix of the bit with respect to both a direction of
ternal shape, the internal structure of these three basic
maximum hardness within each diamond and the forces
forms of diamonds possess extremely similar, if not iden
exerted upon each diamond by the penetrated forma
tion during drilling. It is another object of this invention 50 tical, characteristics of distribution of atoms and chemical
bonds between atoms. Each of these forms of diamonds
to provide a method of orientation of diamonds in the
possesses three axes which are perpendicular to each
matrix of drill bits. It is another object of this inven
other.
a
tion to provide a method of orientation of diamonds in
The cube form ofdiamond, as shown in FIGS. 1 and
drill bits wherein consideration is given to both the direc—
tions of maxim-um hardness in the diamonds and the 55 2., possesses six square faces, eight corners, and twelve
edges. The crystallographic axes of the cube, x, y, and 2,
forces exerted upon each of the diamonds during drilling.
respectively, are found by connecting the center points
In accordance with the invention each of the diamonds
of opposite faces. For example, the y axis may be lo
in a drill bit is set in the matrix of the bit at uniform,
cated by connecting the center of face 20 with the center
predetermined angles and in such a position that one of
of face 21. Each of the faces of the cube is parallel to
the directions of maximum hardness in each diamond 60 two axes of the cube. For example, face 20 is parallel
is positioned so as to oppose the direction of greatest
force exerted upon the diamond by the formation being
drilled.
Referring to the drawings:
to the x and z axes.
For purposes of de?nition, the
term “cube face” as used herein means not only the actual
faces on the exterior of the cube but also any plane
within the cube which is parallel to any two axes of the
FIG. 1 is a perspective view of a cube form of dia 65 cube. It will be recognized that this de?nition will in
clude any internal or external faces which are parallel
mond;
FIG. 2 is a top plan view of the cube form of diamond
to the x and y axes, the x and z axes, and the y and z
axes.
shown in FIG. 1;
One of the directions of maximum hardness in a dia
FIG. 3 is a perspective view of an octahedron form
70 mond and, consequently, one most resistant to abrasion is
of diamond;
the diagonal across a cube face. This direction is repre
FIG. 4 is a top plan view of the octahedron form of
sented in FIGS. 1 and 2 by line 30 which lies in cube face
diamond shown in FIG. 3;
8,027,952
3
4
20. Line 30 is perpendicular to the y axis; it lies in a
plane, cube face 20, which is parallel to the x and z axes;
bisects the 90° angle between axis x2 and axis Z2. Any
line of direction through the dodecahedron which is per
pendicular to one axis and bisects the angle between the
and it bisects the 90° angle between the x and z axes. It
can be seen that any line which is perpendicular to one of
the axes of the cube and bisects the angle between the
other two axes will be a diagonal in a cube face and,
consequently, will ful?ll the quali?cations of one of the
other two axes will be one line of direction of maximum
hardness and by de?nition a diagonal in a cube face.
With a knowledge of the relationship, as discussed
above, between the cube, the octahedron, and the dodeca~
directions of maximum hardness in the diamond, Whether
hedron, these three basic shapes of diamonds may be
oriented in the matrix of a drill 'bit such that one of the
the line be along an exterior surface of the diamond or
along a plane within the diamond.
10 directions of maximum hardness in each diamond will
The above discussion of axes,>cube faces, and directions
of maximum hardness, though given with relation to the
cube form, is equally applicable to the forms of diamonds
represented in FIGS. 3-6.
lie in the desired position in accordance with the inven—
tion. The basic shapes of diamonds have been discussed
in the light of their existing in the ideal, perfect shapes.
It will be apparent to those skilled in ‘the art of crystal
FIGS. 3 and 4 show an octahedron form of diamond 15 lography that such is not the case. It is probably rare
that these ideal basic shapes will be found existing as
crystal which has eight equilateral triangular faces, twelve
edges, and six rectangular pyramid points. The axes of
such in nature. More likely the rule is that the basic
the octahedron, the same as with the cube, are three lines
which lie within the octahedron and are perpendicular to
each other. The axes x1, y1, and Z1 of the octahedron
are located by connecting opposite pyramid points. _ For
example, the yl axis lies along a line connecting point 40
with point 41. A cube face in the octahedron is any
shapes will be distorted to some degree or they may exist
in combination with each other, such as, two' cubes joined,
or a cube and an octahedron joined, so that only a portion
of each basic shape Will be visible to the eye. Perhaps,
only a face or two or a point of any one basic shape will
plane which is parallel to any two of the axes. For
be recognizable. A skilled diamond setter will not ?nd
such irregularities a problem. With the ability to recog
example, in FIG. 3, there is shown a cube face 50 which
is parallel to the x1 and Z1 axes. The cube face 50 cor
responds to cube face 20 shown in the cube in FIG. 1.
nize any of the vpoints ‘or faces of the basic shapes of
diamonds and a knowledge‘ of the positions of the axes of
the basic shapes, the diamonds may be oriented in the
If the cube of FIG. 1 and the octahedron of FIG. 3 were
desired positions in the matrixof a bit.
oriented such that their respective axes would be parallel,
FIG. 7 illustrates the position of an octahedron form
that is, with axis x parallel to axis x1; axis y parallel to 30 of diamond crystal 89 oriented in the matrix 90 of a
drill bit, in accordance with the invention. Also shown
31,; and axis z parallel to axis Z1, any direction in the
octahedron would possess the same hardness character
in FIG. 7 is formation rock 91 being cut by the dia;
istics as the same direction in the cube.
mond. ‘ Reference numeral 92 designates the rock cut as
The line 60
shown in FIG. 3 is along‘a direction in the‘ octahedron
it builds up in the form of a chip along a face of the dia-‘
which possesses the same hardness characteristics as will 35 mond; It is believed that the force primarily responsible
be found in the cube ‘along the line 30. Though line 60
for the wear of a diamond in a drill-bit is that force which
does not appear to be a diagonal line in a vcube face, it is
is exerted upon the diamond ‘by the rock in a formation
by de?nition a diagonal in a cube face inasmuch as it lies
as the diamond cuts through the rock.-_ Theforce ex'e
perpendicular to the yl axis and bisects the angle between
erted by the rock 91 upon the diamond at the time of
the x1 and Z1 axes. “Any direction in the octahedron, such 40 cutting is equal and opposite to the resultant of both a
as that along the line 60, which ful?lls the requirements
vertical, downward force resulting from theweight of the
of a diagonal in a cube ‘face, will be one direction along
bit and drill string upon the diamond and ‘a horizontal
which the diamond will possess maximum resistance to
force in the direction of cutting resulting from the tofque
which must be exerted upon the drill string to efI’ect cut-1
abrasion.
,
FIGS. 5 and 6 show a dodecahedron which possesses 45 ting. In FIG. 7, W is the force upon the diamond ex-'
twelve equal rhombic faces, six rectangular pyramid
ert'ed by the weight of the bit and the drill string, and
points, eight triangular pyramid points, and twenty-four
edges. The dodecahedron, like the cube and octahedron,
T is the force upon the diamond in the direction of cut
has three crystallographic axes positioned perpendicular
Those points which are referred to as
In FIG. 7, reference numeral 93 represents the longii
tudinal axis of the bit. W is parallel to axis 93, and T
rectangular pyramid points are points formed by the
is perpendicular to axis 93 at *a point removed from the
to each other.
ting resulting from the torque applied to the drill string.
junctionrof four rhombic faces. Those points referred
axis. Rd is the resultant of W and T, and Rr is the re
to as triangular pyramid points are the points which are
action force exerted by the rock upon the diamond. At
formed by the junction of three rhombic faces. The axes
the time cutting takes place, the force R-r is equal in
of the‘dodecahedron are along lines drawn between op 55 magnitude and opposite in direction to Rd. A side view
posite rectangular pyramid points. The ‘axes, as shown
of a cube face 50 is illustrated. The diamond is so
in FIG. 5, are x2, y2, and Z2. Axis ya, for example, is
positioned that forces RI and ‘Rd lie in the plane of
located along a line drawn ‘from rectangular pyramid
cube face 50. For any given set of conditions, the di-'
point 70 to rectangular pyramid point 71, which lies op
rection and magnitude of Rd may be determined by
posite point 70. Since the dodecahedron possesses six 60 laboratory experiment. For example, a cutting element,
rectangular pyramid points, connection of each pair of
opposite pyramid points will provide the three crystallo
such as a diamond, may be positioned in the matrix of a
drill bit, a given amount of weight placed on the bit
with the bit resting on a sample of rock to be cut, and
the bit rotated to effect cutting of the rock. The rota
graphic axes. A cube face in the dodecahedron and the
diagonal in the cube face are located in the same manner
as with the cube and octahedron. If the ‘axes of the 65 tional force required to push the cutting element through
dodecahedron are oriented ‘such that they will lie parallel
to the axes of the octahedron and the cube, any direction
in‘ the dodecahedron will possess the same abrasion re—
sistance characteristics as the same direction in? the octa
hedron and the cube. An example of one of the direc 70
tions of maximum hardness in the dodecahedron is illus
trated in FIG. 5 by line 8% which is the diagonal in cube
face 81 which is parallel to the x2 and 22 axes.
In ac
the rock to effect cutting may be measured. Thus, know
ing the weight W on the cutting element and the force T
required for the cutting element to cut the rock, the mag
nitude and direction of the resultant Rd of T and W may
‘be determined.
In connection with FIG. 7, it has been stated that
force W is exerted in a direction parallel to axis 93 of
of the bit and that force T is exerted in a direction per
cordance with the de?nition of a diagonal in a cube face,
pendicular to axis 93. These relations between axis 93
line 80 lies perpendicular to axis yz in a direction which 76 and forces T and W are also illustrated in FIG. 8 which
3,027,952
5
is a diagrammatic perspective view showing the relation
ship of the position of an octahedron diamond 89 to the
axis 93 when the diamond is set in a bit in accordance
with the invention. For purposes of clarity and sim
plicity, the body and matrix of the bit are not shown in
FIG. 8. In FIG. 8, axis 93 is the longitudinal axis of a
drill bit; or stated otherwise, it is the axis about which
the bit rotates when drilling. Line 94 is a theoretical line
which is perpendicular to axis 93 and extends from the
axis through the diamond crystal 89. Line 94 will here 10
6
the force Rd is determined as previously described. As'?
each diamond crystal will be cutting the same type of
rock in the formation for which the bit is designed, the
necessary forces W and T required to effect cutting of
the rock will be the same for all of the diamonds in the
bit; and, consequently, all diamonds will be oriented in
the same respective positions relative to longitudinal axis
of the bit and the radius line for each of the diamonds.
Thus, each diamond is oriented relative to both its own
particular radius line, the longitudinal axis of the bit, and
the direction of the force Rd as determined experimen
inafter be referred to as a radius. Since a large number
of diamonds will be set in the matrix of a bit constructed
tally. This form of orientation, therefore, provides for
in accordance with the invention, it will be readily un
diamond orientation which is based upon the hardness
characteristics of the diamonds employed and the forces
spective radius extending from the axis to the particular 15 encountered While the bit is drilling. This form of
orientation is consequently entirely independent of the
diamond in question. The diamond crystal 89 is posi
plane of the surface of the matrix of the bit.
tioned such that the portion of radius 94 passing through
Though the physical structure of diamonds and their
the diamond crystal lies within cube face 50 as illus
orientation in accordance with the invention have been
trated in FIG. 8. Thus, with the diamond crystal oriented
derstood that each of the diamonds will have its own re
in accordance with the invention, the diamond is so posi 20 discussed in terms of the preferred line of direction of
maximum hardness being the diagonal in a cube face, it
tioned that radius 94 lies within cube face 50 and force
Rd is coincident with the diagonal in cube face. 50'.
Stated in other words, each diamond crystal is so posi
will be recognized by those skilled in the art that there
are other directions within diamonds which possess a
high degree of-hardness. These other directions may be
tioned that a radius drawn to the crystal from the axis
will lie in a cube face of the crystal and the crystal is 25 oriented in a drilling bit in accordance with the inven
tion. For example, in a dodecahedron of diamond, a
so tilted that the force Rd will also lie in the cube face
direction which is considered to possess a high degree
‘of the crystal along the line which is the diagonal in the
of hardness is along the long diagonal in a rhombic face
cube face.
or, stated in other words, along a line in a rhombic face
In FIG. 9: for purposes of simplicity and clarity, only
a cube face 50 is shown to further illustrate the geom 30 between two rectangular pyramid points. In orienting
the diagonal in a rhombic face of a dodecahedron, the
.etry of orienting a diamond crystal in accordance with
diamond is placed in- a matrix of a. bit such that the rhom
rthe invention. FIG. 9 is similar to FIG. 8 in that the
bic face will be in the position of a cube face as pre
longitudinal axis 93 of a drill bit, radius line 94, and
viously described and the diagonal in the rhombic face
cube face 50 are in the same positions, respectively, as
will be in the position of a diagonal in a cube face. The
in FIG. 8. Reference numeral 95 refers to a hypotheti
diagonal in the rhombic face lies perpendicular to a
radius drawn to the diamond from the longitudinal axis
‘and the rhombic face itself will be so positioned that
the face will be coincident with a plane containing the
geometrical terminology into quadrants I, II, III, and IV.
Quadrant I is the upper right quadrant of the cylinder, as 4-0 radius. Considering FIGS. 7 and 9 in the orientation of
the diagonal in the rhombic face of a dodecahedron, the
shown, with the remaining quadrants being numbered
rhombic face may be substituted for cube face 50. Thus,
in a counterclockwise direction. As in FIG. 8, FIG. 9
the rhombic face will lie in quadrants I and III of a
shows the direction of the forces W, T, and Rd with force
hypothetical cylinder generated about radius line 94.
Rd being perpendicular to radius line 94 and cube face
Considering forces T and W, the diagonal in the rhombic
50 being so positioned that Rd is coincident with the di
face will be positioned coincident with the resultant
agonal in the cube face. The plane of cube face 50
lies within quadrants I and III of cylinder 95. It is to
force Rd.
While the invention has been described in connection
be understood that cylinder 95 is purely hypothetical and
with certain speci?c embodiments thereof, it will be un
is shown for the purpose of better illustrating the orien
tation of a diamond in accordance with the invention and 50 derstood that further modi?cations will suggest them
selves to those skilled in the art and it is intended to
forms no part of the actual physical structure of a drill
cover such modi?cations as fall within the scope of the
bit. Considering the orientation illustrated in the light
of an actual bit containing diamonds set in accordance
appended claims.
What is claimed is:
with the invention and assuming the end of the bit in
1. In a drill bit having a body portion provided with
which the ‘diamonds are set as the downward end of the 55
a matrix portion formed thereon, a plurality of diamond
bit and that rotation while drilling is in a clockwise di
cutting elements embedded in said matrix portion and so
rection, it will be recognized that cube face 50 slopes
oriented that a line of direct-ion of maximum hardness in
downward and in the direction of rotation of the bit.
each of said cutting elements is coincident with the re
This may also ‘be observed by reference back to FIG. 7.
FIG. 10 illustrates the general arrangement of one row 60 sultant of the torque and weight forces on each of said
cutting elements necessary to effect cutting of rock of pre
of diamond crystals embedded in the matrix of a drill
determined hardness and the face of said cutting element
bit which is employed in coring a well. Through for
containing said line of direction of maximum hardness is
purposes of clarity only one row of diamonds is shown in
coincident with a plane containing a radius line from and
FIG. 10, it will be readily apparent that a bit will em
ploy a plurality of rows of diamonds distributed over 65 perpendicular to the longitudinal axis of said bit to said
cal right circular cylinder generated about radius line
94 which serves as the axis of the cylinder. Cylinder 95,
as shown, is divided in accordance with Well~known
the entire matrix of the bit. As previously stated, it
will be recognized that though the bit possesses only one
longitudinal axis 93, each of the diamonds 100 set in
ace.
2. In a drill bit having a body portion provided with
a matrix portion formed thereon, a plurality of diamond
cutting elements embedded in said matrix portion, each of
the matrix 90 will have its own radius line extending
from the axis to the diamond as shown in FIGS. 8 and 70 said diamond cutting elements being oriented as follows:
(a) a line of direction of maximum hardness in a face of
‘9. Each diamond is set in the matrix of the bit relative
said cutting element being perpendicular to and inter
to its own radius line and the longitudinal axis of the bit.
secting a radius line extending ‘from and perpendicular to
‘The necessary weight W and the torque force T are de
the longitudinal axis of said bit; (b) the face of said cut
termined experimentally for the particular rock forma
rlllOIl for which the bit is designed, and the direction of 75 ting element containing said line of direction of maximum
3,027,952
8
hardness being coincident with a plane containing said
radius line; and (c) said line of direction of maximum
hardness being Coincident with the resultant of forces T
‘ on said cutting element perpendicular to both said radius
and W, where W is a force on said cutting element parallel
line and said longitudinal axis due ‘to the torque impressed
on said bit, and the magnitude of said forces W and T
is su?icient to effect cutting of rock of predetermined
to the longitudinal axis of said bit due to the Weight im
pressed on said bit, ‘and T is a force on said cutting ele
hardness by said cutting element.
5. In a drill bit having a body portion provided with
ment perpendicular to both said radius line and‘said longi~
a matrix portion formed thereon, a plurality of diamond
cutting elements embedded in said matrix portion, each
tudinal axis due to the torque impressed on said bit, and
the magnitude of said forces W and T is su?icient to
of said diamond cutting elements being so oriented that
etfect cutting of rock of predetermined hardness by said 10 a line of direction of maximum hardness in each of said
cutting elements is coincident with the resultant of forces
cutting element.
T and W, where T is a force on said cutting element per
3. In a drill bit having a body portion provided with
pendicular to the longitudinal axis of said bit due to the
a matrix portion formed thereon, a plurality of diamond
torque impressed on said bit and W is a force on said
cutting elements embedded in sm'd matrix portion and s0
oriented that the diagonal in a cube face in each of said 15 cutting element parallel to said longitudinal axis due to
the weight impressed-on said bit, and the magnitude of
cutting elements is coincident with the resultant of the
said resultant of said forces T and W is su?icient to effect
torque and weight forces on each of said cutting elements
cutting of rock of predetermined hardness by said cutting
necessary to effect cutting of rock of predetermined hard
element.
ness and said cube face is in alignment with a projection
of a radius line from and perpendicular to the longitudinal 20
References Qited in the ?le of this patent
axis of said bit to said cube face.
4. In a drill bit having a body portion provided with
1. Diamond Orientation in Diamond Bits by A. E. Long
a matrix portion formed thereon, a plurality of diamond
and C. B. Slawson, Feb. 1952. Publication of US. Dept.
cutting elements embedded in said matrix portion, each
of Interior, Bureau of Mines, Report of Investigations
of said diamond cutting elements being oriented’ as fol 25 4853.
lows: (a) the diagonal in a cube face of said cutting ele
ment being perpendicular to and intersecting a radius line
extending from and perpendicular to the longitudinal axis
of said bit; (b) the plane of said cube face including said
‘ll. Maximum Hardness Vectors in the Diamond, by
C. B. Slawson and J. A. Cohn. Industrial Diamond Re
view, vol. 10, June 1950, pps. 168-l72.
III. Orientation of Diamonds in Diamond Drill Bits, by
radius line; and (c) said diagonal being coincident with 30 A. E. Long. Industrial Diamond Review, vol. 12, Jan.
1952, pps. 10—14.
the resultant of forces T and W, where W is a force on
IV. Diamond Orientation in Drill Bits, by E. P. P?eider.
said cutting element parallel to the longitudinal axis of
said bit due to the weight on said bit and T is a force
Mining Engineering, vol. 4, Feb., 1952, pps. 177-186,,
UNITED STATES PATENT OFFICE
‘CERTIFICATE OF CORRECTION
Patent No. 3,027,952
April BV 1962
Warren B. Brooks
It is hereby certified that error appears in the above numbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 5, line 62, for "Through" read -— Though ——-5
column 6, line 26, after "dodecahedron" insert —— form ——.,
Signed and sealed this 21st. day of August 1962.
(SEAL)
Attest:
ESTON G. JOHNSON
DAVID L_ LADD
Attesting Officer
Commissioner of Patents
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