Rolling cones with gage cutting elements, earth-boring tools carrying rolling cones with gage cutting elements and related methods

A rolling cone for use on an earth-boring tool includes a frustoconical surface at a proximal end of the rolling cone and an outer surface located distally of the frustoconical surface. The outer surface has a circumferential land surface adjacent the frustoconical surface. The rolling cone includes at least one gage cutting element affixed to the circumferential land surface. A portion of the at least one gage cutting element extends into the frustoconical surface. The at least one gage cutting element includes a volume of superabrasive material disposed on a substrate. A flat surface of the volume of superabrasive material intersects a front cutting face of the volume of superabrasive material. The flat surface is oriented at an acute angle relative to the front cutting face and is located on a side of the at least one gage cutting element that extends into the frustoconical surface of the rolling cone.

TECHNICAL FIELD

Embodiments of the present disclosure relate to rolling cone cutters for earth-boring tools and, more specifically, to rolling cone cutters having gage cutting elements on a heel land adjacent a frustoconical gage surface of the rolling cone cutter.

BACKGROUND

The success of rotary drilling enabled the discovery of deep oil and gas reservoirs and production of enormous quantities of oil. The rotary rock bit was an important invention that made the success of rotary drilling possible. Only soft earthen formations could be penetrated commercially with the earlier drag bit and cable tool, but the two-cone rock bit, invented by Howard R. Hughes, U.S. Pat. No. 930,759, drilled the caprock at the Spindletop field near Beaumont, Tex., with relative ease. That venerable invention, within the first decade of the last century, could drill a scant fraction of the depth and speed of the modern rotary rock bit. The original Hughes bit drilled for hours; the modern bit now drills for days. Modern bits sometimes drill for thousands of feet instead of merely a few feet. Many advances have contributed to the impressive improvements in rotary rock bits.

In drilling wellbores in earthen formations using rolling-cone bits, which may also be characterized as “rock bits,” such bits having one or more rolling cones rotatably mounted thereon are employed. The term “cone” is a term of art, as other shapes of rolling structures used in drilling subterranean formations are conventional. The bit is secured to the lower end of a drill string that is rotated from the surface or by downhole motors or turbines. The cones are rotationally mounted on legs of the bit roll and slide upon the bottom of the wellbore as the drill string is rotated, to engage and disintegrate the formation material to be removed. The rolling cones are provided with cutting elements or teeth, which may be integral with the cones or inserts secured to the cones, that are forced to penetrate and gouge the bottom of the wellbore by weight from the drill string. Other, so-called “hybrid,” drill bits employ rolling cones in combination with fixed cutters mounted on blades extending from the drill bit body. The formation cuttings from the bottom and sides (i.e., the wall) of the wellbore are washed away and disposed by drilling fluid that is pumped down from the surface through the hollow, rotating drill string, and the nozzles as orifices on the drill bit. Eventually the cuttings are carried in suspension in the drilling fluid to the surface up the exterior of the drill string in the wellbore annulus.

BRIEF SUMMARY

In one embodiment of the disclosure, an earth-boring tool includes a bit body and at least one rolling cone rotatably attached to a leg of the bit body. The at least one rolling cone includes a frustoconical surface proximate the leg and an outer surface located distally of the frustoconical surface. The outer surface includes a circumferential land surface adjacent the frustoconical surface and a plurality of cutting inserts and at least one gage cutting element affixed to the circumferential land surface. A portion of the at least one gage cutting element extends into the frustoconical surface, the at least one gage cutting element includes a volume of superabrasive material disposed on a substrate. A flat surface of the volume of superabrasive material intersects a front cutting face of the volume of superabrasive material. The flat surface is oriented at an acute angle relative to the front cutting face and is located on a side of the at least one gage cutting element extending into the frustoconical surface of the at least one rolling cone.

In another embodiment of the disclosure, a rolling cone for use on an earth-boring tool includes a frustoconical surface at a proximal end of the rolling cone and an outer surface located distally of the frustoconical surface. The outer surface has a circumferential land surface adjacent the frustoconical surface. The rolling cone includes at least one gage cutting element affixed to the circumferential land surface. A portion of the at least one gage cutting element extends into the frustoconical surface. The at least one gage cutting element includes a volume of superabrasive material disposed on a substrate. A flat surface of the volume of superabrasive material intersects a central, planar surface of a front cutting face of the volume of superabrasive material. The flat surface is oriented at an acute angle relative to the central, planar surface and is located on a side of the at least one gage cutting element that extends into the frustoconical surface of the rolling cone.

In yet another embodiment of the disclosure, a method of assembling an earth-boring tool includes affixing a rolling cone to a leg of a bit body of the earth-boring tool. The at least one rolling cone includes a frustoconical surface proximate the leg and an outer surface located distally of the frustoconical surface. The outer surface includes a circumferential land surface adjacent the frustoconical surface and a plurality of cutting inserts affixed to the circumferential land surface. At least one gage cutting element is also affixed to the circumferential land surface. A portion of the at least one gage cutting element extends into the frustoconical surface. The gage cutting element includes a volume of superabrasive material disposed on a substrate. A flat surface of the volume of superabrasive material is contiguous with a front cutting face of the volume of superabrasive material. The flat surface is oriented at an acute angle relative to the front cutting face and the flat surface is located on a side of the at least one gage cutting element that extends into the frustoconical surface of the at least one rolling cone.

DETAILED DESCRIPTION

The illustrations presented herein are not actual views of any earth-boring tool, bit, rolling cone, cutting insert, or gage cutting element, but are merely idealized representations employed to describe embodiments of the present disclosure. Additionally, elements common between figures may retain the same numerical designation.

Any headings used herein should not be considered to limit the scope of embodiments of the present disclosure as defined by the appended claims and their legal equivalents. Concepts described in any specific headings are generally applicable in other sections throughout the entire specification.

When used herein in reference to a component configured to be located in a wellbore, the terms “above,” “up,” “upper,” “upward” and “uphole” mean and include a relative position proximate the terranean origin of the well, whereas the terms “below,” “lower,” “down,” “downward,” “downhole” and “bottom” mean and include a relative position distal the terranean origin of the well.

As used herein, the term “longitudinal” refers to a direction parallel to a longitudinal axis of a downhole tool or a longitudinal axis of a component thereof.

As used herein, the term “lateral” refers to a direction orthogonal to a longitudinal axis of a downhole tool or a longitudinal axis of a component thereof.

FIG. 1illustrates an earth-boring tool in the form of a hybrid bit2according to an embodiment of the present disclosure. The bit2may have a central axis L and a bit body6having a threaded section8on its upper end for securing the bit to a drill string (not shown). The bit2has a predetermined gage diameter, which may be defined by one or more of three rolling cones10(two of which are visible inFIG. 1), carrying cutting inserts11, and three fixed blades12(two of which are visible inFIG. 1), carrying cutting elements14, on the bit body6. The bit body6may include three legs16to which the rolling cones10are rotatably mounted. Each rolling cone10and associated leg16may be positioned between adjacent blades12in an alternating relationship on the bit body6. The bit2may include a plurality of nozzles (now shown) for directing drilling fluid toward a bottom of the wellbore in which the bit2may be located and around the rolling cones10and the fixed blades12. It is to be appreciated that the bit2may have any number of rolling cone10cutters, and may have any number of fixed blades12.

FIG. 2illustrates a side view of a rolling cone20, configured generally similar to the rolling cones10ofFIG. 1, for use on an earth-boring tool. It is to be appreciated that the rolling cone20ofFIG. 2may be employed on a hybrid bit, such as the hybrid bit2shown inFIG. 1, as well as on any of the hybrid bits described in U.S. Pat. No. 9,004,198, issued on Apr. 14, 2015, to Kulkarni; and U.S. Pat. No. 8,678,111, issued Mar. 25, 2014, to Zahradnik et al.; and U.S. Patent Application Publication No. 2013/0313021 A1, published on Nov. 28, 2013, in the name of Zahradnik et al., the entire disclosure of each of which is incorporated herein by this reference. The rolling cone20may also be employed on a conventional rolling cone drill bit that does not include fixed blades12, such as a tri-cone bit, a dual cone bit, or any other bit or earth-boring tool, including reamers and hole openers, employing rolling cones.

With continued reference toFIG. 2, the rolling cone20may include a backface22at a proximal end thereof. The backface22may be oriented perpendicular to a longitudinal axis L1of the rolling cone20and may be configured to be located proximate an associated leg16of the bit body6(FIG. 1). The rolling cone20may also include a frustoconical gage surface24located distally of and adjacent the backface22. The gage surface24may be adapted to carry cutting elements that scrape or ream a wall of a wellbore as the rolling cone20rotates about the bottom of the wellbore. Extending between the gage surface24and a distal end26, also termed a “nose,” of the rolling cone20is an outer surface28adapted for carrying cutting inserts that gouge and/or crush formation material at the bottom of the wellbore as the rolling cone20rotates about the wellbore. The outer surface28may be generally conical in shape, as shown inFIG. 2; although, in other embodiments, the outer surface28may have a generally elliptical shape, a generally toroidal shape or other shape. The outer surface28may include a plurality of generally cylindrical or frustoconical segments30,32,34, referred to herein as “lands,” on and in which wear-resistant inserts, cutting inserts and/or cutting elements are mounted to the rolling cone20. Grooves38may be formed in the outer surface28between adjacent lands30,32,34. A first land30, also termed a “heel land,” may be located distally of and adjacent the gage surface24. A second land32may be located distally of the heel land30, and a third land34may be located distally of the second land32. WhileFIG. 2shows three lands30,32,34on the outer surface28of the rolling cone20, it is to be appreciated that more or fewer than three lands may be employed. The gage surface24and the heel land30may converge in a circumferential shoulder40. Although the shoulder40is shown inFIG. 2as being an abrupt edge, it is to be appreciated that the shoulder40may be contoured or rounded.

The rolling cone20may include a plurality of cutting inserts42,44,46mounted to the lands30,32,34of the outer surface28of the rolling cone20. Exposed portions of the cutting inserts42,44,46may be generally conical with rounded tips, as shown inFIG. 2, although numerous other insert shapes and designs are within the scope of the embodiments disclosed herein. By way of non-limiting example, the cutting inserts42,44,46may be shaped according to any of the inserts disclosed in U.S. Pat. No. 6,202,770, issued Mar. 20, 2001, to Jurewicz et al., the entire disclosure of which is incorporated herein by this reference. The cutting inserts42,44,46may include a plurality of heel row inserts42mounted in a circumferential row on the heel land30, a plurality of second row inserts44mounted in a circumferential row on the second land32, and a plurality of third row inserts46mounted in a circumferential row on the third land34. WhileFIG. 2shows a single row of cutting inserts42,44,46on each land30,32,34, it is to be appreciated that each land30,32,34may include two or more circumferential rows of cutting inserts, a plurality of staggered cutting inserts, or no inserts at all. The heel row cutting inserts42, the second row cutting inserts44and the third row cutting inserts46may be arranged and spaced on the outer surface28of the rolling cone20so as not to interfere with rows of cutting inserts on each of any other rolling cones employed on the earth-boring tool.

With continued reference toFIG. 2, a plurality of gage cutting elements50may be mounted in a circumferential row on the heel land30. The gage cutting elements50and the heel row inserts42may be positioned in an alternating circumferential arrangement on the heel land30, although other arrangements are within the scope of the present disclosure. Portions of the gage cutting elements50may extend over the shoulder40and into the gage surface24of the rolling cone20, as discussed in more detail below. The gage cutting elements50may optionally be located in recesses formed in the heel land30and substantially surrounding the associated gage cutting element50. As shown, the gage surface24may be devoid of cutting elements, except for the portions of the gage cutting elements50located on the heel land30and extending into the gage surface24. However, in other embodiments, additional gage cutting elements may be located on the gage surface24.

The gage cutting elements50may generally function to scrape or shear material from a wall of the wellbore to maintain the wellbore at a full gage diameter and prevent erosion and abrasion of the gage surface24of the rolling cone20. The second row inserts44and the third row inserts46may generally function to gouge, crush and remove formation material from the bottom of the wellbore. The gage cutting elements50and the heel row inserts42may complement one another in removal of formation material at a corner junction between the wellbore wall and bottom.

Referring now toFIG. 3, a profile of a gage region of an earth-boring tool employing the rolling cone20ofFIG. 2is provided. The portion of the earth-boring tool shown inFIG. 3may be a portion of a hybrid bit, similar to the hybrid bit2shown inFIG. 1. Profiles of a gage cutting element50, a heel row insert42, and a proximal portion of the outer surface28of the rolling cone20are shown, including the gage surface24, the heel land30and a groove38adjacent the heel land30. The profiles of the foregoing components are taken in a plane extending along the longitudinal axis L1of the rolling cone20(FIG. 2). Because, in the depicted embodiment, the gage cutting elements50and the heel row inserts42are each in respective circumferential rows about the longitudinal axis L1of the rolling cone20, each gage cutting element50and each heel row insert42ofFIG. 2will occupy the respective profiles of the representative gage cutting element50and the representative heel row insert42ofFIG. 3as the rolling cone20rotates about its longitudinal axis L1. Profiles of a gage region53aand a shoulder region53bof a fixed blade of the tool are also provided for reference, as are general cutting profiles53c,53dof cutting elements attached thereto.

The gage cutting element50may include a volume of superabrasive material54disposed on a substrate56. The volume of superabrasive material54may comprise inter-bonded grains of superabrasive material such as, for example, polycrystalline diamond (PCD) comprising synthetic diamond, natural diamond, or a combination of synthetic diamond and natural diamond, or other superabrasive materials (for example, cubic boron nitride), known in the art. The volume of superabrasive material54is often referred to in the art as a “superabrasive table” or a “diamond table” when it comprises polycrystalline diamond.

The substrate56may be formed from a material that is relatively hard and resistant to wear. For example, the substrate56may be formed from and include a ceramic-metal composite (i.e., “cermet”) material. The substrate56may include a cemented carbide material, such as cobalt-cemented tungsten carbide, in which tungsten carbide particles are cemented together in a metallic binder material including cobalt. Other metallic binder materials may include, for example, nickel, iron, or alloys and mixtures thereof. Alternatively, other substrate materials may be used.

The volume of superabrasive material54may include a front cutting face58having a central, planar surface60and a chamfer surface62extending between the central, planar surface60and a peripheral, lateral side surface64of the volume of superabrasive material54. It is to be appreciated that, while the gage cutting element50shown inFIG. 3has a generally cylindrical shape, other shapes are within the scope of the present disclosure. By way of non-limiting example, the gage cutting element50, including the substrate56and the volume of superabrasive material54, may have an elliptical, rectangular, triangular or tombstone shape when viewed in a plane transverse to a longitudinal axis L2of the gage cutting element50. Additionally, while the front cutting face58of the volume of superabrasive material54is shown as having the central, planar surface60, the front cutting face58may include shaped features and non-planar geometries. Moreover, while the substrate56is shown as being generally cylindrical, in other embodiments, the substrate56may have other shapes or features for facilitating insertion and retention of the gage cutting element50in the heel land30of the rolling cone20(FIG. 2).

With continued reference toFIG. 3, the gage cutting element50may be retained within a pocket66extending into the heel land30and the gage surface24of the rolling cone20. The gage cutting element50may be press fitted into the pocket66. In other embodiments, the gage cutting element50may be brazed within the pockets66, which may accomplished with a brazing material selected to provide the gage cutting element50with a higher clearance from the outer surface28of the rolling cone20. The gage cutting element50is shown in position relative to an adjacent heel row insert42, which may be retained within a second pocket67in the heel land30. Also depicted is what is termed a “gage line”68, which represents the maximum radius (i.e., the gage), taken from the central axis L of the tool body to which the rolling cone20is attached, at which the heel row inserts42and/or the gage cutting elements50contact formation material as the tool body rotates within the wellbore and the rolling cone20rotates about its longitudinal axis L1. Stated differently, the gage line68may be said to represent the maximum cutting radius of the at least one rolling cone20, measured from the central axis L of the earth-boring tool. As can be seen, the gage cutting element50and the heel row insert42may each extend to the gage line68. In this configuration, during cutting action of the rolling cone20, the heel row insert42gouges and/or crushes formation material at the gage line68, while the gage cutting element50scrapes, shears and/or abrades remaining formation material up the gage line68relative to the heel row insert42.

A profile of a prior art gage cutting element, referred to herein as a second gage cutting element50′, which is attached strictly to the gage surface24of the rolling cone20, is also depicted. The second gage cutting element50′ is depicted solely for purposes of comparison with the gage cutting element50of the present disclosure. The second gage cutting element50′ is configured cylindrically about longitudinal axis L3somewhat similar to that of the gage cutting element50, and may include a volume of superabrasive material54′ disposed on a substrate56′, with the volume of superabrasive material54′ having a lateral side surface64′ and a front cutting face58′ with a central, planar surface60′ and an annular chamfer surface62′.

Locating the gage cutting element50of the present disclosure primarily on the heel land30, as opposed to strictly on the gage surface24, provides benefits. As can be seen, the second gage cutting element50′ (located entirely on the gage surface24of the rolling cone20) is coincident with the gage line68generally at a single point P1coinciding with a radially outer edge of the central, planar surface60′ of the front cutting face58′ of the second gage cutting element50′. Additionally, the central, planar surface60′ of the second gage cutting element50′ is oriented at an upward acute angle α relative to the gage line68of the tool profile (i.e., the central, planar surface60′ faces uphole and away from the formation material of the wellbore wall during an earth-boring operation). At such an orientation, the second gage cutting element50′ primarily contacts formation material with the downhole-facing portion of the chamfer surface62′ of the volume of superabrasive material54′. Accordingly, the chamfer surface62′ of the second gage cutting element50′ may be considered to be the effective cutting face of the second gage cutting element50′, as the cutting action becomes concentrated at the chamfer surface62′. The angle at which the second gage cutting element50′ engages formation material may be dependent upon the angle of the downhole portion of the chamfer surface62′ relative to the wellbore wall (as analogously represented by the gage line68). Additionally, a total surface contact area between the second gage cutting element50′ and the formation material may be dependent upon the size of the chamfer surface62′ and the angle between the chamfer surface62′ and the gage line68. In relation to the second gage cutting element50′, a minimum clearance between the gage surface24of the rolling cone20and the gage line68must be maintained to prevent accumulation and compacting of formation cuttings directed from the chamfer surface62′ into a narrow downhole gap between the gage surface24and the gage line68adjacent the chamfer surface62′, as more fully described in Pessier, Rudolf C. O. et al.,Rolling Cone Bits with Novel Gauge Cutting Structure Drill Faster, More Efficientlyat 3, FIG. 9 (SPE 30473, Society of Petroleum Engineers, Inc., 1995), the entire disclosure of which is incorporated herein by this reference.

FIG. 4provides a magnified view of the profiles of the gage cutting element50and the second gage cutting element50′ depicted inFIG. 3, and depicts the upward acute angle α of the central, planar surface60′ of the second gage cutting element50′, as well as other respective angles of associated surfaces of the gage cutting element50and the second gage cutting element50′, as set forth below. Thus, for a view of callouts for the angles discussed below, the reader is referred toFIG. 4, while the remainder of the subject matter is also generally shown inFIG. 3.

By locating the gage cutting element50primarily on the heel land30, the central, planar surface60of the front cutting face58may be oriented at a downward acute angle β relative to the gage line68(i.e., the central, planar surface60faces downhole and into the formation material). Stated differently, the gage cutting element50may be located on the rolling cone20such that the central, planar surface60of the front cutting face58is the effective cutting face of the gage cutting element50(i.e., the central, planar surface60faces the downhole direction when the rolling cone20positions the front cutting face58at a maximum radial distance from the central axis L of the earth-boring tool).

The downward acute angle β of the central, planar surface60of the front cutting face58may be between about 5 degrees and about 50 degrees relative to the gage line68. In other embodiments, the downward acute angle β of the central, planar surface60of the front cutting face58may be between about 10 degrees and about 30 degrees relative to the gage line68. At the foregoing downward acute angles β, the gage cutting element50, located on the heel land30, engages formation material with a significantly greater percentage of the surface area of the front cutting face58than that of the second gage cutting element50′ located strictly on the gage surface24of the rolling cone20. Accordingly, the gage cutting element50located on the heel land30is more effective at engaging and removing formation material at the maximum radius (i.e., the gage) of the wellbore, resulting in a smoother, cleaner wellbore wall, than the second gage cutting element50′ located strictly on the gage surface24of the rolling cone20. The orientation of the front cutting face58(i.e., a downhole-facing orientation) when engaging formation material also has the beneficial effect of increasing the longitudinal magnitude, and reducing the lateral magnitude, of cutting forces on the volume of superabrasive material54of the gage cutting element50, reducing the risk of crack formation and subsequent delamination of the volume of superabrasive material54.

Moving the position of the gage cutting element50onto the heel land30also effectively moves the gage cutting element50down the gage line68of the tool profile to a position nearer the heel row insert42, providing more collaboration between the gouging and crushing cutting action of the heel row insert42and the scraping, shearing and/or abrading cutting action of the gage cutting element50. Additionally, locating the gage cutting element50on the heel land30also improves evacuation of formation cuttings from the wellbore. In particular, as the heel row insert42and the gage cutting element50engage and dislodge formation cuttings from the wall of the wellbore, a wider downhole gap (in comparison with that of the second gage cutting element50′) is provided between the gage line68and the cutting face58of the gage cutting element50(and between the gage line68and the outer surface28of the rolling cone20adjacent the cutting face58) to receive formation cuttings emanating from the front cutting face58. Thus, the gage cutting element50located primarily on the heel land30reduces compaction of formation cuttings such that an increased portion of these cuttings are evacuated with the drilling fluid between the gage surface24of the rolling cone20and the wall of the wellbore (as analogously represented by the gage line68) relative to that of the second gage cutting element50′. The presence of the second gage cutting element50′ on the gage surface24of the rolling cone20also unfavorably reduces the area between the gage surface24and the wellbore wall through which the cuttings may be evacuated. By locating the gage cutting element50on the heel land30, an increased area is provided for formation cuttings to be evacuated between the gage surface24and the wellbore wall. Such a configuration further enhances evacuation of formation cuttings, as well as reduces wear on the rolling cone20, thus increasing the efficiency and prolonging the service life of the rolling cone20.

With continued reference toFIGS. 3 and 4, the gage cutting element50may also include a flat surface70, also termed a “flat,” formed on the volume of superabrasive material54and contiguous with the central, planar surface60of the front cutting face58. The flat70may be oriented at an acute angle θ relative to the central, planar surface60of the front cutting face58. As shown, the flat70may extend into the substrate56, although, in other embodiments, the flat70may extend only into the volume of superabrasive material54. The flat70may subsume between about 10% and about 50% of a diameter of the front cutting face58of the gage cutting element50. In some embodiments (such as embodiments where the front cutting face58does not have a planar surface), the flat70may be oriented relative to a plane transverse to the longitudinal axis L2of the gage cutting element50. In such embodiments, the flat70may extend at an acute angle θ of about 45 degrees from a plane transverse to the longitudinal axis L2of the gage cutting element50. However, in other embodiments, the flat70may extend at an acute angle between about 65 degrees and about 25 degrees relative to the plane transverse to the longitudinal axis L2of the gage cutting element50. In further embodiments, the flat70may extend at an angle between about 5 degrees and about 25 degrees from the plane transverse to the longitudinal axis L2of the gage cutting element50. The flat70may be located on a side of the gage cutting element50that extends into the gage surface24of the rolling cone20and may taper from the front cutting face58of the gage cutting element50in a direction generally parallel with the gage surface24of the rolling cone20.

The presence of the flat70in the superabrasive table54of the gage cutting element50allows the location of the gage cutting element50on the heel land30to be moved proximally on the heel land30such that a greater portion of the gage cutting element50is coincident with the gage line68. Accordingly, instead of the gage line68being coincident with only a peripheral edge of the central, planar surface60′ (as in the case of the second gage cutting element50′ located strictly on the gage surface24of the rolling cone20), the gage line68is substantially coincident with an entire edge72between the flat70and the central, planar surface60of the gage cutting element50located on the heel land30, as shown more clearly inFIG. 5. With continued reference toFIG. 5, in this manner, the presence of the flat70in the volume of superabrasive material54provides the gage cutting element50with a greater contact area on formation material at the gage line68, as represented by dashed area74, resulting in a cleaner, smoother wellbore wall.

It is to be appreciated that, in additional embodiments, the gage cutting elements50disclosed herein may be entirely located on the heel land30, with no portion of some or all of the gage cutting elements50extending into the gage surface24. In such embodiments, the gage cutting elements50may be configured to achieve the beneficial results discussed herein by adjusting the one or more of the size, clearance and orientation of the respective gage cutting elements50.

It is also to be appreciated that the rolling cone20disclosed herein may be utilized to repair or retro-fit an earth-boring tool with enhanced gage cutting action. For example, an operator may remove a used, worn, damaged or outdated first rolling cone from an associated leg of the earth-boring tool and affix the rolling cone20disclosed herein in place of the first rolling cone.

Although the foregoing description contains many specifics, these are not to be construed as limiting the scope of the present disclosure, but merely as providing certain exemplary embodiments. Similarly, other embodiments of the disclosure may be devised that do not depart from the spirit or scope of the present disclosure. For example, features described herein with reference to one embodiment also may be provided in others of the embodiments described herein. The scope of the disclosure is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the disclosed embodiments, which fall within the meaning and scope of the claims, are encompassed by the present disclosure.