Attack Tool with an Interruption

Abstract

A tool has a wear-resistant steel base comprising a shank suitable for attachment to a driving mechanism. A planar end of a cemented metal carbide segment is brazed to an interfacial surface of the steel base axially opposed to the shank. At least one interruption is formed in the interfacial surface.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/766,865 filed on Jun. 22, 2007 entitled Attack Tool with an Overhang. U.S. patent application Ser. No. 11/766,865 is a continuation-in-part of U.S. patent application Ser. No. 11/742,304 which was filed on Apr. 30, 2007 and entitled Pick with a Bearing Assembly and is now U.S. Pat. No. 7,475,948 that issued on Jan. 13, 2009. U.S. patent application Ser. No. 11/742,304 is a continuation of U.S. patent application Ser. No. 11/742,261 which was filed on Apr. 30, 2007 and entitled Lubricated Pick and is now U.S. Pat. No. 7,469,971 that issued on Dec. 30, 2008. U.S. patent application Ser. No. 11/742,261 is a continuation-in-part of U.S. patent application Ser. No. 11/464,008 which was filed on Aug. 11, 2006 and entitled Holder for a Degradation Assembly and is now U.S. Pat. No. 7,338,135 that issued on Mar. 4, 2008. U.S. patent application Ser. No. 11/464,008 is a continuation-in-part of U.S. patent application Ser. No. 11/463,998 which was filed on Aug. 11, 2006 and entitled Washer for a Degradation Assembly and is now U.S. Pat. No. 7,384,105 that issued on Jun. 10, 2008. U.S. patent application Ser. No. 11/463,998 is a continuation-in-part of U.S. patent application Ser. No. 11/463,990 which was filed on Aug. 11, 2006 and entitled An Attack Tool and is now U.S. Pat. No. 7,320,505 that issued on Jan. 22, 2008. U.S. patent application Ser. No. 11/463,990 is a continuation-in-part of U.S. patent application Ser. No. 11/463,975 which was filed on Aug. 11, 2006 and entitled An Attack Tool and is now U.S. Pat. No. 7,445,294 that issued on Nov. 4, 2008. U.S. patent application Ser. No. 11/463,975 is a continuation-in-part of U.S. patent application Ser. No. 11/463,962 which was filed on Aug. 11, 2006 and entitled An Attack Tool and is now U.S. Pat. No. 7,413,256 that issued on Aug. 19, 2008. The present application is also a continuation-in-part of U.S. patent application Ser. No. 11/695,672 which was filed on Apr. 3, 2007 and entitled Core for a Pick and is now U.S. Pat. No. 7,396,086 that issued on Jul. 8, 2008. U.S. patent application Ser. No. 11/695,672 is a continuation-in-part of U.S. patent application Ser. No. 11/686,831 filed on Mar. 15, 2007 and entitled A Superhard Composite Material Bonded to a Steel Body and is now U.S. Pat. No. 7,568,770 that issued on Aug. 4, 2009. All of these applications are herein incorporated by reference for all that they contain.

BACKGROUND OF THE INVENTION

The present invention relates to an improved cutting element or insert that may be used in machinery such as crushers, picks, grinding mills, roller cone bits, rotary fixed cutter bits, earth boring bits, percussion bits or impact bits, and drag bits.

U.S. Pat. No. 6,733,087 to Hall, et al., which is herein incorporated by reference for all that it contains, discloses an attack tool for working natural and man-made materials that is made up of one or more segments, including a steel alloy base segment, an intermediate carbide wear protector segment, and a penetrator segment comprising a carbide substrate that is coated with a superhard material. The segments are joined at continuously curved surfaces vary from one another at about their apex in order to accommodate ease of manufacturing and to concentrate the bonding material in the region of greatest variance. The carbide used for the penetrator and the wear protector may have a cobalt binder, or it may be binderless. It may also be produced by the rapid omnidirectional compaction method as a means of controlling grain growth of the fine cobalt particles. The parts are brazed together in such a manner that the grain size of the carbide is not substantially altered. The superhard coating may consist of diamond, polycrystalline diamond, cubic boron nitride, binderless carbide, or combinations thereof.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a tool has a wear-resistant steel base comprising a shank suitable for attachment to a driving mechanism. A planar end of a cemented metal carbide segment is brazed to an interfacial surface of the steel base axially opposed to the shank. The interfacial surface of the steel base has a diameter smaller than a base diameter of the carbide segment.

A superhard tip may be bonded to the cemented metal carbide segment and may have a diameter larger than an upper diameter of the carbide segment. The superhard tip may be brazed to the cemented metal carbide with a braze comprising a thickness of 1.0 to 50 microns. The superhard tip may comprise a material selected from the group consisting of polycrystalline diamond, vapor-deposited diamond, natural diamond, cubic boron nitride, infiltrated diamond, layered diamond, diamond impregnated carbide, diamond impregnated matrix, silicon bonded diamond, or combinations thereof. A braze used between the planar end of the cemented metal carbide segment and the interfacial surface of the base may comprise silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, zinc, or combinations thereof. The braze may also comprise a thickness of 0.001 to 0.010 inch.

The base diameter of the carbide segment may overhang the diameter of the interfacial surface by 0.001 to 0.100 inch. The outside surface of the carbide segment may be ground down to 0.010 to 0.050 inch. Further, the outside surface of the carbide segment may be ground down to 0.020 to 0.030 inch. A portion of the steel base may be inserted into a pocket formed within the carbide segment. The cemented metal carbide segment may comprise a concave surface.

In another aspect of the present invention, a method has steps for assembling an attack tool. A superhard tip has a diamond piece bonded to a carbide substrate and a wear-resistant steel base has a shank. An interfacial surface of the steel base and a base surface of the superhard tip are brazed to opposite surfaces of a cemented metal carbide segment. An overhang is formed between the carbide segment and the steel base and the interfacial surface of the steel base has a diameter smaller than a base diameter of the carbide segment. The superhard tip may also overhang the carbide segment at an interface at which they are brazed together, with the superhard tip having a base diameter greater than a diameter of an upper surface of the carbide segment. The base diameter of the superhard tip may be ground down to 0.001 to 0.010 inch. The overhang formed by the carbide segment may be ground down to 0.010 to 0.050 inch. It is believed that grinding down the outer surfaces of the carbide segments may increase the wear life of the attack tool. At least one interruption may be formed within the interfacial surface of the steel base. The overhang may have a concave or a convex region. Also, a portion of the overhang may be covered with a stop-off material.

In another aspect of the invention, at least one interruption is formed in the interfacial surface. The interruption may have a plurality of notches formed within the interfacial surface. The steel base may be formed by forging, machining, or a combination thereof. A supporting piece may be press fit into the at least one interruption. The supporting piece may comprise a hard material selected from the group consisting of carbide, chromium, tungsten, tantalum, niobium, titanium, molybdenum, natural diamond, polycrystalline diamond, vapor deposited diamond, cubic boron nitride, TiN, AlNi, AlTiNi, TiAlN, CrN/CrC/(Mo, W)S2, TiN/TiCN, AlTiN/MoS2, TiAlN, ZrN, diamond impregnated carbide, diamond impregnated matrix, silicon bonded diamond, or combinations thereof. The press fit may have an interference of 0.0005 to 0.0050 inch. The cemented metal carbide segment and/or the base may comprise a concave surface. The plurality of interruptions may have various geometries and dimensions. Some embodiments may comprise circular and/or rectangular geometries.

The at least one interruption may comprise a width of 5 percent to 75 percent a width of the interfacial surface of the steel base. In some embodiments, the width of the interruption may be 35 percent to 55 percent of the width of the interfacial surface of the steel base. The at least one interruption may also comprise a depth of 10 percent to 75 percent of a height of a body portion of the steel base. In some embodiments, the depth of the interruption is 25 percent to 55 percent of the height of the body portion of the steel base. At least one interruption may be formed in a planar end of the cemented metal carbide segment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of attack tools on a rotating drum attached to a motor vehicle.

FIG. 2 is a perspective diagram of an embodiment of an attack tool.

FIG. 3 is a perspective diagram of another embodiment of an attack tool.

FIG. 4 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 5 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 6 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 7 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 8 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 9 is a cross-sectional diagram of another embodiment of an attack tool.

FIG. 10 is a perspective diagram of another embodiment of an attack tool

FIG. 11 is an exploded perspective diagram of an embodiment of an attack tool.

FIG. 12 is a sectional diagram of an embodiment of an interfacial surface of a base of an attack tool.

FIG. 13 is a sectional diagram of another embodiment of an interfacial surface of a base of an attack tool

FIG. 14 is a sectional diagram of another embodiment of an interfacial surface of a base of an attack tool

FIG. 15 is a sectional diagram of another embodiment of an interfacial surface of a base of an attack tool

FIG. 16 is a sectional diagram of another embodiment of an interfacial surface of a base of an attack tool

FIG. 17 is perspective diagram of an embodiment of a trencher.

FIG. 18 is an orthogonal diagram of another embodiment of a trencher.

FIG. 19 is a diagram of an embodiment of a method for manufacturing an attack tool.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a cross-sectional diagram of an embodiment of a plurality of attack tools 100a attached to a rotating drum 101 connected to the underside of a pavement milling machine 102. The milling machine 102 may be a cold planar used to degrade manmade formations, such as pavement 103 prior to the placement of a new layer of pavement. Picks or attack tools 100a may be attached to the rotating drum 101, which rotates and brings the attack tools 100a into engagement with the formation. A holder 104 may be attached to the rotating drum 101 and an attack tool 100a may be inserted into the holder 104. The holder 104 may hold the attack tool 100a at an angle offset from the direction of rotation, such that the attack tool 100a engages the pavement 103 at a preferential angle.

FIGS. 2 and 3 show two embodiments of an attack tool 100b and 100c, respectively, each having a wear-resistant steel base 200a, 200b, with a shank 201a, 201b suitable for attachment to a driving mechanism. A planar end 202a, 202b of a cemented metal carbide segment 203a, 203b may be brazed to an interfacial surface 204a, 204b of the steel base 200a, 200b axially opposed to the shank 201a, 201b. The interfacial surface 204a, 204b of the steel base 200a, 200b may have a diameter 210a, 210b smaller than a base diameter 212a, 212b of the planar end 202a, 202b of the carbide segment 203a, 203b, thus forming an overhang 205a, 205b, respectively. It is believed that having the overhang 205a, 205b may improve the life of the attack tool 100b, 100c. An outside surface 214a, 214b of the cemented metal carbide segment 203a, 203b may be ground down to 0.010 to 0.050 inch in order to smooth over cracks that may have been formed in the surface 214a, 214b of the cemented metal carbide segment 203a, 203b during manufacturing. This may also increase the life as well as increase the efficiency of the attack tool 100b, 100c. A superhard tip 206a, 206b may be bonded to the cemented metal carbide segment 203a, 203b. In a preferred embodiment, the superhard tip 206a, 206b may be brazed to the cemented metal carbide segment 203a, 203b. The superhard tip 206a, 206b may comprise a carbide substrate bonded to a harder material. The harder material selected from the group consisting of polycrystalline diamond, vapor-deposited diamond, natural diamond, cubic boron nitride, infiltrated diamond, layered diamond, diamond impregnated carbide, diamond impregnated matrix, silicon bonded diamond, or combinations thereof. In some embodiments, the steel base 200a, 200b may comprise hard-facing to increases its wear resistance. In some embodiments the attack tool 100b, 100c may include a washer having a layer of hardfacing.

FIGS. 4 through 9 illustrate cross-sectional diagrams of various embodiments of an attack tool. In some embodiments, an attack tool 100d includes at least one interruption 400a formed in an interfacial surface 204c of a steel base 200c as shown in FIG. 4. The interfacial surface 204c may have a diameter 452 smaller than a base diameter 212c of a planar end 202c of a cemented metal carbide segment 203c, forming an overhang 205c. The cemented metal carbide segment 203c may be brazed to the steel base 200c with a braze comprising silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, zinc, or combinations thereof.

During an operation in which the attack tool 100d is exposed to high temperatures, the steel base 200c and the cemented metal carbide segment 203c, which have different coefficients of thermal expansion, may expand and contract at different rates, weakening the bond between the steel base 200c and the cemented metal carbide segment 203c and thereby weakening the attack tool 100d.

A surprising result shows that by forming the at least one interruption 400a in the interfacial surface 204c of the steel base 200c, the braze bond maintains its strength and thereby the life of the attack tool 100d increases. The at least one interruption 400 may comprise a width 451 of 5 percent to 75 percent of the diameter 452 of the interfacial surface of the steel base 200c. The interruption 400 may also comprise a depth 450 of 5 percent to 75 percent of a height 453 of a body portion 460 of the steel base 200c.

A superhard tip 206c may be bonded to the cemented metal carbide segment 203c. In some embodiments, the superhard tip 206c may have a diameter 218 larger than an upper diameter 220 of the cemented metal carbide segment 203c such that the superhard tip 206c overhangs the cemented metal carbide segment 203c at a surface 401 in which superhard tip 206c and the cemented metal carbide segment 203c are bonded together. It is believed that an overhang 470 formed between the superhard tip 206c and the cemented metal carbide segment 203c may increase the life of the superhard tip 206c during operation. In the embodiment of FIG. 4, the cemented metal carbide segment 203c may comprise a concave surface 480 and a body portion of the steel base 200c may comprise a concave surface 481.

In FIG. 5, an embodiment of an attack tool 100e includes a plurality of interruptions 400b and interruption 402 formed in an interfacial surface 204d of a steel base 200d. The interruptions 400b and 402 may extend into the steel base 200d at various depths and have various widths. The interruptions 400b and 402 may be substantially coaxial. The depths of the interruptions 400b and 402 may be formed into the steel base 200d such that the interruptions provide strength to the attack tool 100e while maintaining its structural integrity during an operation.

In some embodiments of an attack tool 100f, a supporting piece 600 may be press-fit into an interruption 400c, as shown in the embodiment of FIG. 6. The supporting piece 600 may comprise a hard material such as carbide, chromium, tungsten, tantalum, niobium, titanium, molybdenum, natural diamond, polycrystalline diamond, vapor deposited diamond, cubic boron nitride, TiN, AlNi, A1TiNi, TiAlN, CrN/CrC/(Mo, W)S2, TiN/TiCN, AlTiN/MoS2, TiAlN, ZrN, diamond impregnated carbide, diamond impregnated matrix, silicon bonded diamond, or combinations thereof. The supporting piece 600 may help to strengthen a steel base 200e. The supporting piece 600 may be press-fit into the interruption 400c. The press-fit may comprise an interference of 0.0005 inches to 0.0050 inches. It is believed that a supporting piece 600 press-fit into the interruption 400c may limit the shrinkage of an interfacial surface 204e of the steel base 200e during a cooling step in the brazing process.

In some embodiments of an attack tool 100g, a portion 700a of a steel base 200f may be inserted into a pocket 701a formed within a cemented metal carbide segment 203d. In the embodiment of FIG. 7, the steel base 200f may not have an interruption formed in an interfacial surface 204f of the steel base 200f.

In FIG. 8, an embodiment of an attack tool 100h includes a portion 700b of a steel base 200g inserted into a pocket 701b formed within a cemented metal carbide segment 203e. However, in the embodiment of FIG. 8, the steel base 200g may have an interruption 400d formed in an interfacial surface 204g of the steel base 200g. The attack tool 100h may comprise an overhang 205d in which a base diameter 212d of the cemented metal carbide segment 203e may overhang a diameter 210c of the interfacial surface 204g by a distance 800 of 0.001 inch to 0.100 inch.

FIG. 9 shows an embodiment of an attack tool 100i with a plurality of interruptions 400e disposed in an interfacial surface 204h of a steel base 200h, as well as a plurality of interruptions 900 disposed within a planar end 202d of a cemented metal carbide segment 203f. In this embodiment, the steel base 200h may have a concave surface 950. In this embodiment, the overhanging portion 952 of the cemented metal carbide segment 203f may comprise a convex region 953. In other embodiments, the overhanging portion 952 may comprise a concave region (not shown). The overhanging portion 952 may also be coated with a stop-off material 951 such that a braze used to bond the cemented metal carbide segment 203f and the steel base 200h together does not contact the overhanging portion 952 or a portion 954 of the cemented metal carbide segment 203f proximal a superhard tip 206. The stop-off material 951 may comprise boron nitride, copper, nickel, cobalt, gold, silver, manganese, magnesium, palladium, titanium, niobium, zinc, phosphorous, boron, aluminum, cadmium, chromium, tin, silicon, tantalum, yttrium, metal oxide, ceramic, or combinations thereof. It may be beneficial to coat the overhanging portion 952 with a stop-off material 951 such that the stop-off material 951 resists excess braze that may flow from the interfacial surface 204h between the cemented metal carbide segment 203f and the steel base 200h.

In other embodiments of an attack tool, a steel base with an interfacial surface comprises a tapered portion. The tapered portion comprises at least one interruption. Also a carbide segment comprises an overhang in these embodiments, although in other embodiments, there may be no overhang. The tapered portion of the interfacial surface may reduce residual stresses generated during brazing. Also the tapered portion may also strengthen the attack tool during side loading.

FIG. 10 discloses an attack tool 100j with a wear-resistant steel base 200i having a shank 201 c adapted for attachment to a trenching machine. An interfacial surface 204i of the steel base 200i may have a diameter 210d smaller than a base diameter 212e of a cemented metal carbide segment 203g, forming an overhang 205e. The base diameter 212e of the cemented metal carbide segment 203g may overhang the diameter 210d of the interfacial surface 204i by 0.001 inch to 0.100 inch.

FIG. 11 is an exploded perspective diagram of an embodiment of an attack tool 100k. The attack tool 100k comprises a wear-resistant base 200j suitable for attachment to a driving mechanism and a cemented metal carbide segment 203h. A planar end 202e of the cemented metal carbide segment 203h may be bonded to an interfacial surface 204j of the base 200j axially opposed to a shank 201d. A bond between the cemented metal carbide segment 203h and the base 200j may be a braze 1150 comprising silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, zinc, or combinations thereof. The braze 1150 may comprise a thickness of 0.001 to 0.010 inch. A superhard tip 206e may be bonded to the cemented metal carbide segment 203h. The superhard tip 206 may be brazed to the cemented metal carbide segment 203h with a braze 1100 having a thickness of 1.0 to 10 microns. The superhard tip 206 may also have a diameter 1101 that is larger than an upper diameter 1102 of the cemented metal carbide segment 203h. The interfacial surface 204j of the base 200j may have a diameter 210e smaller than a base diameter 1103 of the cemented metal carbide segment 203h. The base diameter 1103 may overhang the diameter 210e of the interfacial surface 204j by 0.001 to 0.100 inch. In some embodiments, an outside surface of the cemented metal carbide segment 203h may be ground down 0.010 inch to 0.050 inch. It is believed that grinding down the outer surface may increase the life of the attack tool 100k.

Various sectional diagrams of embodiments of an interfacial surface of a steel base of an attack tool are shown in FIGS. 12 through 16. In FIG. 12, an interruption 400f may be formed in an interfacial surface 204i, the interruption 400f being concentric with an outer surface 1200 of the interfacial surface 204i.

In some embodiments, a plurality of interruptions may be formed in the interfacial surface. Referring now to FIG. 13, an interruption 400g may be concentric with a second interruption 1300 in an interfacial surface 204j. The interruptions 400g, 1300, comprise circular geometries.

FIG. 14 illustrates another embodiment of an interfacial surface 204k having a plurality of interruptions 400h. In this embodiment, the plurality of interruptions 400h may comprise rectangular geometries.

In some embodiments, the at least one interruption 400i may have a plurality of notches 1504 formed within an interfacial surface 204l. Such embodiments may be formed by forging, machining, or a combination thereof. FIG. 15 illustrates a plurality of notches 1500 formed within an outer surface 1502 of the interfacial surface 204l as well as plurality of notches 1504 formed within an inner surface 1501 of the interfacial surface 204l. It is believed that during operation, the notches 1500, 1504 formed within a base may lower the stress imposed on the attack tool, thereby extending the life of the attack tool.

FIG. 16 shows another embodiment of an interfacial surface 204m having a plurality of notches 1600, 1604 formed within an outer surface 1602 and an inner surface 1601. In this embodiment, the notches 1600, 1604 may be gradual and less defined than the notches 1500, 1504 in the embodiment of the interfacial surface 204l shown in FIG. 15.

FIGS. 17 and 18 show various wear applications that may be incorporated with the present invention. Attack tools 1001 may be disposed on a rock wheel trenching machine 1700 as shown in FIG. 17. Also, attack tools 100m may be placed on a chain that rotates around an arm 1802 of a chain trenching machine 1800, as shown in FIG. 18.

FIG. 19 is a diagram of an embodiment of a method 1900 for manufacturing an attack tool. The method 1900 includes providing 1901 a superhard tip comprising a diamond piece bonded to a carbide substrate, a wear-resistant steel base comprising a shank, and a cemented metal carbide segment. The method 1900 also includes simultaneously brazing 1902 an interfacial surface of the base to a planar base of the cemented metal carbide segment and brazing the superhard tip to an upper surface of the carbide segment. The method 1900 further includes forming 1903 an overhang between the carbide segment and the steel base.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.

Claims

1. An attack tool for degrading natural and man-made formations comprising:

a base, said base including: a shank for attachment to a driving mechanism; a body portion having a height; and, an interfacial surface spaced apart from said shank, said interfacial surface having a diameter and at least one interruption formed in said interfacial surface; and,

a carbide segment, said carbide segment including: a planar end coupled to said interfacial surface with a braze, said planar end having a base diameter larger than said diameter of said interfacial surface.

a supporting piece separate from said carbide segment, said supporting piece held at least partly within said interruption with a press-fit, said supporting piece including a surface that with an another surface of said interruption defines a space.

2. The attack tool of claim 1, further comprising a superhard tip spaced apart from said planar end and bonded to said carbide segment.

3. The attack tool of claim 2, wherein said superhard tip is brazed to said carbide segment with a braze having a thickness of 1.0 microns to 10 microns.

4. (canceled)

5. The attack tool of claim 2, wherein said superhard tip comprises at least one material selected from a group consisting of polycrystalline diamond, vapor-deposited diamond, natural diamond, cubic boron nitride, infiltrated diamond, layered diamond, diamond impregnated carbide, diamond impregnated matrix, and silicon bonded diamond.

6. The attack tool of claim 1, wherein said braze comprises at least one of silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, and zinc.

7. The attack tool of claim 1, wherein said braze has a thickness of 0.001 inch to 0.010 inch.

8. (canceled)

9. (canceled)

10. (canceled)

11. The attack tool of claim 1, wherein said press fit comprises an interference of 0.0005 inch to 0.0050 inch.

12. The attack tool of claim 1, wherein said supporting piece comprises at least one material selected from a group consisting of carbide, chromium, tungsten, tantalum, niobium, titanium, molybdenum, natural diamond, polycrystalline diamond, vapor deposited diamond, cubic boron nitride, TiN, AlNi, AlTiNi, TiAlN, CrN/CrC/(Mo, W)S2, TiN/TiCN, AlTiN/MoS2, TiAlN, ZrN, diamond impregnated carbide, diamond impregnated matrix, and silicon bonded diamond.

13. The attack tool of claim 1, further comprising at least another interruption formed in said planar end of said carbide segment.

14. The attack tool of claim 1, wherein said carbide segment includes a concave surface.

15. The attack tool of claim 1, wherein said base includes a concave surface.

16. The attack tool of claim 1, wherein said at least one interruption comprises a width of 5 percent to 75 percent of said diameter of said interfacial surface.

17. The attack tool of claim 1, wherein said at least one interruption comprises a depth of 5 percent to 75 percent of said height of said body portion of said base.

18. (canceled)

19. The attack tool of claim 1, wherein said at least one interruption comprises a circular geometry.

20. (canceled)