Title:
Cutter Pocket Inserts
Kind Code:
A1


Abstract:
A method for optimizing drill bit design and an optimized drill bit for drilling a well in an earth formation, wherein, in one embodiment, the optimized drill bit comprises a bit body with a plurality blades spaced along the bit body, each blade having a curved outer edge, a substantially flat forward face, and a number of insert pockets milled into each blade. A cutter insert is preferably secured into each insert pocket. The inserts are selected to give a desired cutter orientation, which is preferably independent of the orientation of the insert. Finally, a cutter is preferably secured at least partially within each cutter insert. The insert pockets may be formed by a cylindrical flat ended mill oriented substantially orthogonal to an outer edge of the blade, thereby creating the insert pockets with two substantially flat sidewalls, a curved endwall, and a substantially flat bottom.



Inventors:
Prevost, Gregory C. (Spring, TX, US)
Application Number:
12/198997
Publication Date:
03/04/2010
Filing Date:
08/27/2008
Assignee:
BAKER HUGHES INCORPORATED (Houston, TX, US)
Primary Class:
International Classes:
E21B10/46
View Patent Images:
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Primary Examiner:
MICHENER, BLAKE E
Attorney, Agent or Firm:
LOCKE LORD LLP (600 TRAVIS SUITE 2800, HOUSTON, TX, 77002-3095, US)
Claims:
What is claimed is:

1. A method of optimizing a drill bit, such as for drilling a well into an earth formation, the method comprising the steps of: producing a bit body having a number of blades, each blade having at least one insert pocket formed therein; selecting a cutter insert having a cutter pocket to give a desired orientation to a cutter; securing the insert at least partially within the insert pocket; and securing the cutter at least partially within the cutter pocket of the insert.

2. The method at set forth in claim 1, wherein the insert pocket comprises two sidewalls substantially parallel to each other and a substantially flat bottom substantially perpendicular to the sidewalls.

3. The method at set forth in claim 1, wherein the insert pocket comprises a flat bottom substantially perpendicular to a face of the blade.

4. The method at set forth in claim 1, wherein the insert is selected from a plurality of inserts, each insert potentially providing a different orientation to the cutter.

5. The method at set forth in claim 1, wherein an orientation of the insert is independent of the orientation of the cutter, such that the orientation of the cutter pocket within the insert provides the orientation of the cutter.

6. The method at set forth in claim 1, wherein the insert is welded to the bit body.

7. The method at set forth in claim 1, wherein the cutter is brazed to the insert.

8. The method at set forth in claim 1, wherein the orientation comprises a back rake.

9. The method at set forth in claim 1, wherein the orientation comprises a side rake.

10. The method at set forth in claim 1, wherein the orientation comprises a cutter exposure.

11. A method of optimizing a drill bit, such as for drilling a well into an earth formation, the method comprising the steps of: producing a bit body having a number of blades; milling a number of insert pockets into each blade using a cylindrical flat ended mill, each insert pocket having an insert orientation; selecting, for each insert pocket, a cutter insert to give a desired cutter orientation, the cutter orientation being independent of the insert orientation; securing, for each insert pocket, the selected insert within the insert pocket; and securing a cutter at least partially within each cutter insert.

12. The method at set forth in claim 11, wherein the insert pocket comprises two sidewalls substantially parallel to each other and a flat bottom substantially perpendicular to the sidewalls and substantially perpendicular to a face of the blade.

13. The method at set forth in claim 11, wherein each insert is selected from a plurality of inserts, each insert potentially providing a different cutter orientation.

14. The method at set forth in claim 13, wherein the different cutter orientations potentially provided by the plurality of inserts comprise different back rakes, side rakes and exposures.

15. The method at set forth in claim 11, wherein the cutter orientation comprises a back rake.

16. The method at set forth in claim 11, wherein the cutter orientation comprises a side rake.

17. The method at set forth in claim 11, wherein the cutter orientation comprises a cutter exposure.

18. The method at set forth in claim 11, wherein, during the milling step, the mill is oriented substantially orthogonal to an outer edge of the blade.

19. An optimized drill bit, such as for drilling a well into an earth formation, the drill bit comprising: a bit body having a number of blades; a number of insert pockets milled into each blade, each insert pocket having an insert orientation; a cutter insert welded into each insert pocket, the insert selected to give a desired cutter orientation, the cutter orientation being independent of the insert orientation; and a cutter brazed at least partially within each cutter insert.

20. The drill bit as set forth in claim 19, wherein the insert pockets are formed by a cylindrical flat ended mill oriented substantially orthogonal to an outer edge of the blade, such that the insert pocket comprises two sidewalls substantially parallel to each other and a flat bottom substantially perpendicular to the sidewalls and substantially perpendicular to a face of the blade.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The inventions disclosed and taught herein relate generally to drill bits for drilling wells; and more specifically relate to drill bits with super-abrasive cutting elements for drilling wells in earth formations.

2. Description of the Related Art

U.S. Pat. No. 5,487,436 discloses a “method of forming a cutter assembly for a rotary drill bit comprises locating in a mould a preform polycrystalline diamond cutting element of a non-thermally stable type, packing powdered matrix-forming material, such as powdered tungsten carbide, around at least part of the cutting element within the mould, and then infiltrating the powdered material with a metal alloy in a furnace to form a body of solid infiltrated matrix in which the cutting element is at least partly embedded. The metal alloy is selected to provide an infiltration temperature, for example of up to about 850°, which is not greater than the temperature at which significant thermal degradation of the cutting element would occur.”

U.S. Pat. No. 5,678,645 discloses a mounting apparatus “for locking an insertable stud cutter or slug cutter or fluid nozzle into a socket on a rotatable earth boring drill bit. The cutter may be readily removed and replaced without damaging either the cutter, nozzle or bit. Apparatus are shown for permitting, or alternatively, preventing rotation of the cutter or nozzle in its socket. The mounting apparatus is particularly applicable to cutters having a cutting disk of polycrystalline diamond or other superabrasive material mounted on a carbide supporting body, or carbide body nozzles or nozzles having a bore lined with such a material.”

U.S. Pat. No. 5,737,980 discloses “[t]hin walled metal alloy receptacles [that] are filled with a filler material. If granular, the filler material is solidified in the receptacles. The receptacles are inserted in a bit mold with their open ends abutting against preformed cutter locations in the bit mold. The mold is filled with a steel or tungsten carbide powder and a binder and exposed to temperatures sufficient to cause the binder to infiltrate the steel or tungsten carbide as well as infiltrate the receptacle outer surfaces, metallurgically bonding the receptacles to the binder. The mold is then removed, revealing a bit body with the bonded filled receptacles. The filler material is removed from the receptacles PCD cutters are inserted in the receptacles and are brazed using conventional brazing techniques.”

U.S. Pat. No. 5,906,245 discloses a “[m]ounting apparatus is described for locking an insertable stud cutter or slug cutter or fluid nozzle into a socket on a rotatable earth boring drill bit. The cutter may be readily removed and replaced without damaging either the cutter, nozzle or bit. Apparatus are shown for permitting or, alternatively, preventing rotation of the cutter or nozzle in its socket. The mounting apparatus is particularly applicable to cutters having a cutting disk of polycrystalline diamond or other superabrasive material mounted on a carbide supporting body, or carbide body nozzles or nozzles having a bore lined with such a material.”

U.S. Pat. No. 6,142,250 discloses “[f]ormation engaging elements [that] are moveably mounted onto a drill bit. Such elements may be used to protect other rigidly mounted formation engaging elements from impacts that occur during use of the drill bit, or they may be used to alter the aggressiveness of the drill bit when used in directional drilling operations.”

U.S. Pat. No. 7,070,011 discloses a “steel body rotary drag bit for drilling a subterranean formation includes a plurality of support elements affixed to the bit body, each forming at least a portion of a cutting element pocket. Each of a plurality of cutting elements has a substantially cylindrical body and is at least partially disposed within a cutter pocket. At least a portion of the substantially cylindrical body of each cutting element is directly secured to at least a portion of a substantially arcuate surface of the bit body. At least a portion of a substantially planar surface of each cutting element matingly engages at least a portion of a substantially planar surface of a support element.”

U.S. Pat. No. 7,216,565 discloses a “steel body rotary drag bit for drilling a subterranean formation includes a plurality of support elements affixed to the bit body, each forming at least a portion of a cutting element pocket. Each of a plurality of cutting elements has a substantially cylindrical body and is at least partially disposed within a cutter pocket. At least a portion of the substantially cylindrical body of each cutting element is directly secured to at least a portion of a substantially arcuate surface of the bit body. At least a portion of a substantially planar surface of each cutting element matingly engages at least a portion of a substantially planar surface of a support element.”

U.S. Patent Application No. 20070157763 discloses “an improved method for manufacturing a drill bit. The method includes applying a hardfacing material to the drill bit, forming a cutter pocket within the drill bit with plunge EDM, and inserting a cutting element into the cutter pocket.”

The inventions disclosed and taught herein are directed to an improved drill bit.

BRIEF SUMMARY OF THE INVENTION

The invention relates to a drill bit, such as for drilling a well into an earth formation, comprising a bit body, having a number of blades and a number of insert pockets milled into each blade. A cutter insert is preferably secured into each insert pocket. The inserts are selected to give a desired cutter orientation, which is preferably independent of the orientation of the insert. Finally, a cutter is preferably secured at least partially within each cutter insert. The insert pockets may be formed by a cylindrical flat ended mill oriented substantially orthogonal to an outer edge of the blade, thereby creating the insert pockets with two substantially flat sidewalls, a curved endwall, and a substantially flat bottom.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an exemplary drill bit incorporating cutting elements and embodying certain aspects of the present inventions;

FIG. 2 is an enlarged perspective view of an exemplary cutting element embodying certain aspects of the present inventions;

FIG. 3 is a close-up partial elevation view of a blade of a drill bit according to certain aspects of the present inventions;

FIG. 4 is a partial sectional view of a blade of a drill bit according to certain aspects of the present inventions; and

FIG. 5 is a partial plan view of a blade of a drill bit according to certain aspects of the present inventions.

DETAILED DESCRIPTION

The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicants have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Lastly, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims.

Particular embodiments of the invention may be described below with reference to block diagrams and/or operational illustrations of methods. In some alternate implementations, the functions/actions/structures noted in the figures may occur out of the order noted in the block diagrams and/or operational illustrations. For example, two operations shown as occurring in succession, in fact, may be executed substantially concurrently or the operations may be executed in the reverse order, depending upon the functionality/acts/structure involved.

Applicants have created a method for optimizing drill bit design and an optimized drill bit for drilling a well in an earth formation. In one embodiment, the optimized drill bit comprises a bit body; a plurality blades spaced along the bit body, each blade having a curved outer edge, a substantially flat forward face, and a number of insert pockets milled into each blade. A cutter insert is preferably secured into each insert pocket. The inserts are selected to give a desired cutter orientation, which is preferably independent of the orientation of the insert. Finally, a cutter is preferably secured at least partially within each cutter insert. The insert pockets may be formed by a cylindrical flat ended mill oriented substantially orthogonal to an outer edge of the blade, thereby creating the insert pockets with two substantially flat sidewalls, a curved endwall, and a substantially flat bottom.

FIG. 1 is an illustration of a drill bit 10 that includes a bit body 12 having a conventional pin end 14 to provide a threaded connection to a conventional jointed tubular drill string rotationally and longitudinally driven by a drilling rig. Alternatively, the drill bit 10 may be connected in a manner known within the art to a bottomhole assembly which, in turn, is connected to a tubular drill string or to an essentially continuous coil of tubing. Such bottomhole assemblies may include a downhole motor to rotate the drill bit 10 in addition to, or in lieu of, being rotated by a rotary table or top drive located at the surface or on an offshore platform (not shown within the drawings). Furthermore, the conventional pin end 14 may optionally be replaced with various alternative connection structures known within the art. Thus, the drill bit 10 may readily be adapted to a wide variety of mechanisms and structures used for drilling subterranean formations.

The drill bit 10, and select components thereof, are preferably similar to those disclosed in U.S. Pat. No. 7,048,081, which is incorporated herein by specific reference. In any case, the drill bit 10 preferably includes a plurality of blades 16 each having a forward facing surface, or face 18. The drill bit 10 may have anywhere from three to eight blades 16. In a preferred embodiment, the drill bit 10 has three blades, which has been found to actually reduce wear, improve penetration, and increase cutter life. For example, according to one example, an eight bladed bit experienced 60% more wear that a three bladed bit, under identical circumstances. The drill bit 10 also preferably includes a row of cutters, or cutting elements, 20 secured to the blades 16. The drill bit 10 also preferably includes a plurality of nozzles 22 to distribute drilling fluid to cool and lubricate the drill bit 10 and remove cuttings. As customary in the art, gage 24 is the maximum diameter which the drill bit 10 is to have about its periphery. The gage 24 will thus determine the minimum diameter of the resulting bore hole that the drill bit 10 will produce when placed into service. The gage 24 of a small drill bit may be as small as a few centimeters and the gage 24 of an extremely large drill bit may approach a meter, or more. Between each blade 16, the drill bit 10 preferably has fluid slots, or passages, 26 into with the drilling fluid is fed by the nozzles 22.

An exemplary cutting element 20 of the present invention, as shown in FIG. 2, includes a super-abrasive cutting table 28 of circular, rectangular or other polygon, oval, truncated circular, triangular, or other suitable cross-section. The super-abrasive table 28, exhibiting a circular cross-section and an overall cylindrical configuration, or shape, is suitable for a wide variety of drill bits and drilling applications. The super-abrasive table 28 of the cutting element 20 is preferably formed with a conglomerated super-abrasive material, such as a polycrystalline diamond compact (PDC), with an exposed cutting face 30. The cutting face 30 will typically have a top 30A and a side 30B with the peripheral junction thereof serving as the cutting region of the cutting face 30 and more precisely a cutting edge 30C of the cutting face 30, which is usually the first portion of the cutting face 30 to contact and thus initially “cut” the formation as the drill bit 10 retaining the cutting element 20 progressively drills a bore hole. The cutting edge 30C may be a relatively sharp approximately ninety-degree edge, or may be beveled or rounded. The super-abrasive table 28 will also typically have a primary underside, or attachment, interface face joined during the sintering of the diamond, or super-abrasive, layer forming the super-abrasive table 28 to a supporting substrate 32 typically formed of a hard and relatively tough material such as a cemented tungsten carbide or other carbide. The substrate 32 may be pre-formed in a desired shape such that a volume of particulate diamond material may be formed into a polycrystalline cutting, or super-abrasive, table 28 thereon and simultaneously strongly bonded to the substrate 32 during high pressure high temperature (HPHT) sintering techniques practiced within the art. A unitary cutting element 20 will thus be provided that may then be secured to the drill bit 10 by brazing or other techniques known within the art.

In accordance with the present invention, the super-abrasive table 28 preferably comprises a heterogeneous conglomerate type of PDC layer or diamond matrix in which at least two different nominal sizes and wear characteristics of super-abrasive particles, such as diamonds of differing grains, or sizes, are included to ultimately develop a rough, or rough cut, cutting face 30, particularly with respect to the cutting face side 30B and most particularly with respect to the cutting edge 30C. In one embodiment, larger diamonds may range upwards of approximately 600 μm, with a preferred range of approximately 100 μm to approximately 600 μm, and smaller diamonds, or super-abrasive particles, may preferably range from about 15 μm to about 100 μm. In another embodiment, larger diamonds may range upwards of approximately 500 μm, with a preferred range of approximately 100 μm to approximately 250 μm, and smaller diamonds, or super-abrasive particles, may preferably range from about 15 μm to about 40 μm.

The specific grit size of larger diamonds, the specific grit size of smaller diamonds, the thickness of the cutting face 30 of the super-abrasive table 28, the amount and type of sintering agent, as well as the respective large and small diamond volume fractions, may be adjusted to optimize the cutter 20 for cutting particular formations exhibiting particular hardness and particular abrasiveness characteristics. The relative, desirable particle size relationship of larger diamonds and smaller diamonds may be characterized as a tradeoff between strength and cutter aggressiveness. On the one hand, the desirability of the super-abrasive table 28 holding on to the larger particles during drilling would dictate a relatively smaller difference in average particle size between the smaller and larger diamonds. On the other hand, the desirability of providing a rough cutting surface would dictate a relatively larger difference in average particle size between the smaller and larger diamonds. Furthermore, the immediately preceding factors may be adjusted to optimize the cutter 20 for the average rotational speed at which the cutting element 20 will engage the formation as well as for the magnitude of normal force and torque to which each cutter 20 will be subjected while in service as a result of the rotational speeds and the amount of weight, or longitudinal force, likely to be placed on the drill bit 10 during drilling.

Referring also to FIG. 3, FIG. 4, and FIG. 5, each blade 16 preferably includes a curved outer edge 34 substantially perpendicular to the face 18 of each blade 16. In a preferred embodiment, one or more insert pockets 36 are milled into each blade 16. More specifically, in some embodiments, a number of insert pockets 36 are milled into the outer edge 34 of each blade. A cutter insert 38 is preferably secured within each insert pocket 36. Each cutter insert 38 preferably includes an integral cutter pocket 40, into which one of the cutters 20 is secured. The cutter inserts 38 are preferably brazed and/or welded into the insert pockets 36. The cutters 20 are preferably brazed into the cutter pockets 40. However, the cutter inserts 38 and cutters 20 may be attached or secured using other techniques, such as those known in the industry.

In some embodiments, the insert pockets 36 are standardized, such that the same insert pockets 36 are milled into relatively large numbers of bit bodies 12. The cutters 20 may also be standardized, such that relatively large quantities of cutters 20 may be manufactured and/or ordered without regard to the finally optimized drill bit 10. Standardizing the bit bodies 12 and cutters 20, simplifies manufacturing and procurement, thereby increasing production efficiency.

One will appreciate, however, that all drill bits 10 are not created equal. Often, a drill bit 10 needs to be designed, manufactured, and/or selected for a specific application. In addition to choices between materials used throughout the drill bit 10, the size, shape, number, and orientation of the cutters 20 is often critical to drill bit optimization for a given application.

It can be appreciated that the term orientation, as in cutter orientation, refers to back rake, side rake, exposure, angle around, and/or the three dimensional position, attitude, and/or alignment of the cutters 20 with respect to the blade 16. Back rake, generally, refers to a vertical angle of the cutter 20. The face 18 of the blade 16, especially where the face 18 is substantially vertical, may provide a reference for a back rake angle. Side rake, generally, refers to a horizontal angle of the cutter 20. The face 18 of the blade 16, especially where the face 18 is substantially planar, may provide a reference for a side rake angle. Cutter exposure, generally, refers to how far the cutters 20 extend beyond the blade 16 into the earth formation being drilled. One can appreciate that a cutter 20 must extend beyond the blade 16 and that different angles may be useful in different applications. While the cutters 20 preferably extend both forwardly and outwardly of the blades 16, the inserts 38 may or may not extend beyond the blades 16.

Thus, according to the teachings of the present invention, the drill bits 10 are optimized by selecting appropriate cutter inserts 38 for the application. More specifically, an optimized drill bit 10 may be produced using a bit body 12 having standardized insert pockets 36 by selecting appropriate cutter inserts 38 that will accommodate the desired cutter size, shape, number, and/or orientation, such as back rake, side rake, and/or exposure. More specifically, for a given application, a drill bit designer may select a bit body 12 constructed of the desired materials. The bit body 12 may be of a standardized size, shape, blade count, and/or other configurable characteristics. The bit body 12 may have standardized insert pockets 36 pre-milled into the blades. Alternatively, the bit designer may specify a number and/or pattern for the insert pockets 36, which the designer or a technician then mills into the bit body 12.

Then, the designer decides the size, shape, number, and orientation of the cutters 20. Each cutter 20 may have a unique size, shape, and/or orientation. Alternatively, some or even all of the cutters 20 may share the same size, shape, and/or orientation. In either case, for each cutter 20, the designer then selects the appropriate cutter inserts 38 according to the desired cutters' 20 size, shape, and/or orientation. The selected inserts 38 are then brazed and/or welded into the insert pockets 36 of the bit body 12. For example, the inserts 38 may be brazed and then tack welded into place. Finally, the selected cutters 20 are then brazed into the cutter pockets 40 of the inserts 38. Of course, as discussed above, the cutter inserts 38 and cutters 20 may be attached or secured using other techniques, such as those known in the industry.

In some embodiments, the insert pockets 36 are milled into the outer edge 34 of the blades 16 using a cylindrical flat-ended mill. The resulting insert pockets 36 may therefore have two substantially flat, or planar, parallel sidewalls 42 and an arcuate, or curved, end wall 44. In some embodiments, the milling is performed with the mill substantially orthogonal to the outer edge 34, thereby providing the insert pockets 36 with a substantially flat bottom 46, which may be substantially perpendicular to the sidewalls and substantially perpendicular to the face 18 of the blade 16.

It can be seen that, in a preferred embodiment, each insert pocket 36, and corresponding insert 38, has a size, shape, and/or orientation that is independent of the cutter 20 size, shape, and/or orientation. The drill bit 10 is optimized by selecting the appropriate cutter insert 38 to provide, or accommodate, the desired cutters' 20 size, shape, and/or orientation. Thus, in order to create a variety of drill bits 10, the designer may use a standardized bit body 12 and standardized cutters 20, only needing a plurality of inserts 38 to potentially provide a number of different cutter orientations.

The blades 16 of the bit body 12 are preferably made from steel, but may be made from an alloy matrix, a matrix of carbide powder impregnated with a copper alloy binder during a casting process, a carbide matrix formed from a sintering process. However, the blades 16 and/or the bit body 12 may be constructed of virtually any metal, alloy, or casting, depending on the expected application and/or properties desired. For example, the drill bit 10 may be constructed as a steel body drill bit using a casting process whereby the steel is heated past its melting temperature and allowed to flow, under the influence of gravity, into a graphite mold. Alternatively, the drill bit 10 may be constructed as a matrix style drill bit using an infiltration casting process whereby the copper alloy binder is heated past its melting temperature and allowed to flow, under the influence of gravity, into a matrix of carbide powder packed into, and shaped by, the graphite mold. In any case, the mold is preferably a graphite negative of the shape of the drill bit 10. The mold preferably contains the shapes of the blades 16 and slots 26 of the drill bit 10, creating a form for the drill bit 10. Other features may be made from clay and/or sand and attached to the mold.

A mold assembly may also include one or more displacement elements. For example, the mold assembly may include a plurality of nozzle displacements to accommodate the eventual installation of the nozzles 22. The displacements may be made of glued sand, a clay material, and/or graphite. For example, they may consist of a graphite outer layer filled with sand.

The mold assembly may also include a plurality of cutter insert displacements. The cutter insert displacements are small graphite pieces that retain the physical positions of cutter inserts 38 in the matrix and resulting bit. Once the bit has been successfully molded, the insert pockets 36 formed by the displacements may be further machined to provide locations into which the inserts 38 are braised, welded, and/or otherwise secured.

Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. Further, the various methods and embodiments of the drill bit 10 can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. For example, one cutter insert 38 may accommodate more than one cutter 20.

The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicants, but rather, in conformity with the patent laws, Applicants intend to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims.