Patent Publication Number: US-9903165-B2

Title: Drill bits with axially-tapered waterways

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/914,233, filed Jun. 10, 2013, entitled “DRILL BITS WITH AXIALLY-TAPERED WATERWAYS,” which is now U.S. Pat. No. 9,074,429, which is a continuation of U.S. patent application Ser. No. 12/638,229, filed Dec. 15, 2009, entitled “DRILL BITS WITH AXIALLY-TAPERED WATERWAYS,” which is now U.S. Pat. No. 8,459,381, which is a continuation-in-part of U.S. patent application Ser. No. 12/564,779, filed on Sep. 22, 2009, entitled “DRILL BITS WITH ENCLOSED FLUID SLOTS,” which is now U.S. Pat. No. 7,918,288, and U.S. patent application Ser. No. 12/564,540, filed on Sep. 22, 2009, entitled “DRILL BITS WITH ENCLOSED FLUID SLOTS AND INTERNAL FLUTES,” which is now U.S. Pat. No. 7,828,090, both of which are continuations of U.S. patent application Ser. No. 11/610,680, filed Dec. 14, 2006, entitled “CORE DRILL BIT WITH EXTENDED CROWN HEIGHT,” which is now U.S. Pat. No. 7,628,228. U.S. patent application Ser. No. 12/638,229 is also a continuation-in-part of U.S. patent application Ser. No. 12/567,477, filed Sep. 25, 2009, entitled “DRILL BITS WITH ENCLOSED SLOTS,” which is now U.S. Pat. No. 7,958,954, and which is a division of U.S. patent application Ser. No. 11/610,680, filed Dec. 14, 2006, entitled “CORE DRILL BIT WITH EXTENDED CROWN HEIGHT,” which is now U.S. Pat. No. 7,628,228. U.S. patent application Ser. No. 12/638,229 is also a continuation-in-part of U.S. patent application Ser. No. 12/568,231, filed on Sep. 28, 2009, entitled “DRILL BITS WITH INCREASED CROWN HEIGHT,” which is now U.S. Pat. No. 7,874,384, and U.S. patent application Ser. No. 12/568,204, filed on Sep. 28, 2009, entitled “DRILL BITS WITH NOTCHES AND ENCLOSED SLOTS,” now U.S. Pat. No. 7,909,119, both of which are divisionals of U.S. patent application Ser. No. 11/610,680, filed Dec. 14, 2006, entitled “CORE DRILL BIT WITH EXTENDED CROWN HEIGHT,” which is now U.S. Pat. No. 7,628,228. The contents of each of the above-referenced patent applications and patents are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     The present invention generally relates to drilling tools that may be used to drill geological and/or manmade formations and to methods of manufacturing and using such drilling tools. 
     2. Technical Background 
     Drill bits and other boring tools are often used to drill holes in rock and other formations for exploration or other purposes. One type of drill bit used for such operations is an impregnated drill bit. Impregnated drill bits include a cutting portion or crown that may be formed of a matrix that contains a powdered hard particulate material, such as tungsten carbide. The hard particulate material may be sintered and/or infiltrated with a binder, such as a copper alloy. Furthermore, the cutting portion of impregnated drill bits may also be impregnated with an abrasive cutting media, such as natural or synthetic diamonds. 
     During drilling operations, the abrasive cutting media is gradually exposed as the supporting matrix material is worn away. The continuous exposure of new abrasive cutting media by wear of the supporting matrix forming the cutting portion can help provide a continually sharp cutting surface. Impregnated drilling tools may continue to cut efficiently until the cutting portion of the tool is consumed. Once the cutting portion of the tool is consumed, the tool becomes dull and typically requires replacement. 
     Impregnated drill bits, and most other types of drilling tools, usually require the use of drilling fluid or air during drilling operations. Typically, drilling fluid or air is pumped from the surface through the drill string and across the bit face. The drilling fluid may then return to the surface through a gap between the drill string and the borehole wall. Alternatively, the drilling fluid may be pumped down the annulus formed between the drill string and the formation, across the bit face and return through the drill string. Drilling fluid can serve several important functions including flushing cuttings up and out of the bore hole, clearing cuttings from the bit face so that the abrasive cutting media cause excessive bit wear, lubricating and cooling the bit face during drilling, and reducing the friction of the rotating drill string. 
     To aid in directing drilling fluid across the bit face, drill bits will often include waterways or passages near the cutting face that pass through the drill bit from the inside diameter to the outside diameter. Thus, waterways can aid in both cooling the bit face and flushing cuttings away. Unfortunately, when drilling in broken and abrasive formations, or at high penetration rates, debris can clog the waterways, thereby impeding the flow of drilling fluid. The decrease in drilling fluid traveling from the inside to the outside of the drill bit may cause insufficient removal of cuttings, uneven wear of the drill bit, generation of large frictional forces, burning of the drill bit, or other problems that may eventually lead to failure of the drill bit. Furthermore, frequently in broken and abrasive ground conditions, loose material does not feed smoothly into the drill string or core barrel. 
     Current solutions employed to reduce clogging of waterways include increasing the depth of the waterways, increasing the width of the waterways, and radially tapering the sides of the waterways so the width of the waterways increase as they extend from the inside diameter to the outside diameter of the drill bit. While each of these methods may reduce clogging and increase flushing to some extent, they also each present various drawbacks to one level or another. 
     For example, deeper waterways may decrease the strength of the drill bit, reduce the velocity of the drilling fluid at the waterway entrance, and therefore, the flushing capabilities of the drilling fluid, and increase manufacturing costs due to the additional machining involved in cutting the waterways into the blank of the drill bit. Wider waterways may reduce the cutting surface of the bit face, and therefore, reduce the drilling performance of the drill bit and reduce the velocity of the drilling fluid at the waterway entrance. Similarly, radially tapered waterways may reduce the cutting surface of the bit face and reduce the velocity of the drilling fluid at the waterway entrance. 
     One will appreciate that many of the current solutions may remove a greater percentage of material from the inside diameter of the drill bit than the outside diameter of the drill bit in creating waterways. The reduced bit body volume at the inside diameter may result in premature wear of the drill bit at the inside diameter. Such premature wear can cause drill bit failure and increase drilling costs by requiring more frequent replacement of the drill bit. 
     Accordingly, there are a number of disadvantages in conventional waterways that can be addressed. 
     SUMMARY 
     Implementations of the present invention overcome one or more problems in the art with drilling tools, systems, and methods that can provide improved flow of drilling fluid about the cutting face of a drilling tool. For example, one or more implementations of the present invention include drilling tools having waterways that can increase the velocity of drilling fluid at the waterway entrance, and thereby, provide improved flushing of cuttings. In particular, one or more implementations of the present invention include drilling tools having axially-tapered waterways. 
     For example, one implementation of a core-sampling drill bit can include a shank and an annular crown. The annular crown can include a longitudinal axis, a cutting face, an inner surface, and an outer surface. The annular crown can define an interior space about the longitudinal axis for receiving a core sample. The drill bit can further include at least one waterway extending from the inner surface to the outer surface of the annular crown. The at least one waterway can be axially tapered whereby the longitudinal dimension of the at least one waterway at the outer surface of the annular crown is greater than the longitudinal dimension of the at least one waterway at the inner surface of the annular crown. 
     Additionally, an implementation of a drilling tool can include a shank and a cutting portion secured to the shank. The cutting portion can include a cutting face, an inner surface, and an outer surface. The drilling tool can also include one or more waterways defined by a first side surface extending from the inner surface to the outer surface of the cutting portion, an opposing second side surface extending from the inner surface to the outer surface of the cutting portion, and a top surface extending between the first side surface and second side surface and from the inner surface to the outer surface of the cutting portion. The top surface can taper from the inner surface to the outer surface of the cutting portion in a direction generally from the cutting face toward the shank. 
     Furthermore, an implementation of an earth-boring drill bit can include a shank and a crown secured to and extending away from the shank. The crown can include a cutting face, an inner surface, and an outer surface. The drill bit can further include a plurality of notches extending into the cutting face a first distance at the inner surface and extending into the cutting face a second distance at the outer surface. The second distance can be greater than said first distance, and the plurality of notches can extend from the inner surface to the outer surface of the crown. 
     An implementation of a method of forming a drill bit having axially-tapered waterways can involve forming an annular crown comprised of a hard particulate material and a plurality of abrasive cutting media. The method can also involve placing a plurality of plugs within the annular crown. Each plug of the plurality of plugs can increase in longitudinal dimension along the length thereof from a first end to a second opposing end. The method can additionally involve infiltrating the annular crown with a binder material configured to bond to the hard particulate material and the plurality of abrasive cutting media. Furthermore, the method can involve removing the plurality of plugs from the infiltrated annular crown to expose a plurality of axially-tapered waterways. 
     In addition to the foregoing, a drilling system can include a drill rig, a drill string adapted to be secured to and rotated by the drill rig, and a drill bit adapted to be secured to the drill string. The drill bit can include a shank and an annular crown. The annular crown can include a longitudinal axis, a cutting face, an inner surface, and an outer surface. The annular crown can define an interior space about the longitudinal axis for receiving a core sample. The annular crown can also include at least one waterway extending from the inner surface to the outer surface. The at least one waterway can be axially tapered whereby the longitudinal dimension of the at least one waterway at the outer surface of the annular crown is greater than the longitudinal dimension of the at least one waterway at the inner surface of the annular crown. 
     Additional features and advantages of exemplary implementations of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It should be noted that the figures are not drawn to scale, and that elements of similar structure or function are generally represented by like reference numerals for illustrative purposes throughout the figures. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a perspective view of a drilling tool including axially-tapered waterways according to an implementation of the present invention; 
         FIG. 2  illustrates a bottom view of the drilling tool of  FIG. 1 ; 
         FIG. 3  illustrates a partial cross-sectional view of the drilling tool of  FIG. 2  taken along the section line  3 - 3  of  FIG. 2 ; 
         FIG. 4  illustrates a perspective view of a drilling tool including axially-tapered and radially-tapered waterways according to an implementation of the present invention; 
         FIG. 5  illustrates a bottom view of the drilling tool of  FIG. 4 ; 
         FIG. 6  illustrates a partial cross-sectional view of the drilling tool of  FIG. 5  taken along the section line  6 - 6  of  FIG. 5 ; 
         FIG. 7  illustrates a bottom view of a drilling tool including axially-tapered and double radially-tapered waterways according to another implementation of the present invention; 
         FIG. 8  illustrates a perspective view of a drilling tool including axially-tapered notches and axially-tapered enclosed slots according to an implementation of the present invention; 
         FIG. 9  illustrates a cross-sectional view of the drilling tool of  FIG. 8  taken along the section line  9 - 9  of  FIG. 8 ; 
         FIG. 10  illustrates a partial cross-sectional view of the drilling tool of  FIG. 9  taken along the section line  10 - 10  of  FIG. 9 ; 
         FIG. 11  illustrates a schematic view a drilling system including a drilling tool having axially-tapered waterways in accordance with an implementation of the present invention; 
         FIG. 12  illustrates a perspective view of plug for use in forming drilling tools having axially-tapered waterways in accordance with an implementation of the present invention; 
         FIG. 13  illustrates a side view of the plug of  FIG. 11 ; and 
         FIG. 14  illustrates a top view of the plug of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     Implementations of the present invention are directed towards drilling tools, systems, and methods that can provide improved flow of drilling fluid about the cutting face of a drilling tool. For example, one or more implementations of the present invention include drilling tools having waterways that can increase the velocity of drilling fluid at the waterway entrance, and thereby, provide improved flushing of cuttings. In particular, one or more implementations of the present invention include drilling tools having axially-tapered waterways. 
     One will appreciate in light of the disclosure herein that axially-tapered waterways according to one or more implementations of the present invention can ensure that the opening of the waterway in the inner surface of the drilling tool can is smaller than the opening of the waterway in the outer surface of the drilling tool. Thus, the waterway can act like a nozzle by increasing the velocity of the drilling fluid at the waterway entrance in the inner surface of the drilling tool. The capability of axially-tapered waterways to increase the velocity of the drilling fluid at the waterway entrance can provide increased flushing of cuttings, and can help prevent clogging of the waterways. Furthermore, axially-tapered waterways can provide improved flow of drilling fluid without significantly sacrificing bit body volume at the inside diameter or reducing the cutting surface of the bit face. Thus, the axially-tapered waterways of one or more implementations of the present invention can provide for increased drilling performance and increased drilling life. 
     In addition, or alternatively, to having axially-tapered waterways, in one or more implementations of the present invention the drilling tools can include axially and radially-tapered waterways, or in other words, double-tapered waterways. One will appreciate in light of the disclosure therein that double-tapered waterways can help ensure that the waterway increases in dimensions in each axis as it extends from the inner surface of the drilling tool to the outer surface of the drilling tool. The increasing size of a double-tapered waterway can reduce the likelihood of debris lodging within the waterway, and thus, increase the drilling performance of the drilling tool. 
     Furthermore, double-tapered waterways can also allow for a smaller waterway opening at the inside diameter, while still allowing for a large waterway opening at the outside diameter. Thus, one or more implementations of the present invention can increase the amount of matrix material at the inside diameter, and thus, help increase the life of the drill bit while also providing effective flushing. The increased life of such drill bits can reduce drilling costs by reducing the need to trip a drill string from the bore hole to replace a prematurely worn drill bit. 
     The drilling tools described herein can be used to cut stone, subterranean mineral formations, ceramics, asphalt, concrete, and other hard materials. These drilling tools can include, for example, core-sampling drill bits, drag-type drill bits, roller-cone drill bits, reamers, stabilizers, casing or rod shoes, and the like. For ease of description, the Figures and corresponding text included hereafter illustrate examples of impregnated, core-sampling drill bits, and methods of forming and using such drill bits. One will appreciate in light of the disclosure herein; however, that the systems, methods, and apparatus of the present invention can be used with other drilling tools, such as those mentioned hereinabove. 
     Referring now to the Figures,  FIGS. 1 and 2  illustrate a perspective view and a top view, respectively, of a drilling tool  100 . More particularly,  FIGS. 1 and 2  illustrate an impregnated, core-sampling drill bit  100  with axially-tapered waterways according to an implementation of the present invention. As shown in  FIG. 1 , the drill bit  100  can include a shank or blank  102 , which can be configured to connect the drill bit  100  to a component of a drill string. The drill bit  100  can also include a cutting portion or crown  104 . 
       FIGS. 1 and 2  also illustrate that the drill bit  100  can define an interior space about its central axis  106  for receiving a core sample. Thus, both the shank  102  and crown  104  can have a generally annular shape defined by an inner surface  107  and outer surface  108 . Accordingly, pieces of the material being drilled can pass through the interior space of the drill bit  100  and up through an attached drill string. The drill bit  100  may be any size, and therefore, may be used to collect core samples of any size. While the drill bit  100  may have any diameter and may be used to remove and collect core samples with any desired diameter, the diameter of the drill bit  100  can range in some implementations from about 1 inch to about 12 inches. As well, while the kerf of the drill bit  100  (i.e., the radius of the outer surface minus the radius of the inner surface) may be any width, according to some implementations the kerf can range from about ¼ inches to about 6 inches. 
     The crown  104  can be configured to cut or drill the desired materials during the drilling process. In particular, the crown  104  of the drill bit  100  can include a cutting face  109 . The cutting face  109  can be configured to drill or cut material as the drill bit  100  is rotated and advanced into a formation. As shown by  FIGS. 1 and 2 , in one or more implementations, the cutting face  109  can include a plurality of grooves  110  extending generally axially into the cutting face  109 . The grooves  110  can help allow for a quick start-up of a new drill bit  100 . In alternative implementations, the cutting face  109  may not include grooves  110  or may include other features for aiding in the drilling process. 
     The cutting face  109  can also include waterways that may allow drilling fluid or other lubricants to flow across the cutting face  109  to help provide cooling during drilling. For example,  FIG. 1  illustrates that the crown  104  can include a plurality of notches  112  that extend from the cutting face  109  in a generally axial direction into the crown  104  of the drill bit  100 . Additionally, the notches  112  can extend from the inner surface  107  of the crown  104  to the outer surface  108  of the crown  104 . As waterways, the notches  112  can allow drilling fluid to flow from the inner surface  107  of the crown  104  to the outer surface  108  of the crown  104 . Thus, the notches  112  can allow drilling fluid to flush cuttings and debris from the inner surface  107  to the outer surface  108  of the drill bit  100 , and also provide cooling to the cutting face  109 . 
     The crown  104  may have any number of notches that provides the desired amount of fluid/debris flow and also allows the crown  104  to maintain the structural integrity needed. For example,  FIGS. 1 and 2  illustrate that the drill bit  100  includes nine notches  112 . One will appreciate in light of the disclosure herein that the present invention is not so limited. In additional implementations, the drill bit  100  can include as few as one notch or as many 20 or more notches, depending on the desired configuration and the formation to be drilled. Additionally, the notches  112  may be evenly or unevenly spaced around the circumference of the crown  104 . For example,  FIG. 2  depicts nine notches  112  evenly spaced from each other about the circumference of the crown  104 . In alternative implementations, however, the notches  112  can be staggered or otherwise not evenly spaced. 
     As shown in  FIGS. 1 and 2 , each notch  112  can be defined by at least three surfaces  112   a ,  112   b ,  112   c . In particular, each notch  112  can be defined by a first side surface  112   a , an opposing side surface  112   b , and a top surface  112   c . In some implementations of the present invention, each of the sides surfaces  112   a ,  112   b  can extend from the inner surface  107  of the crown  104  to the outer surface  108  of the crown  104  in a direction generally normal to the inner surface of the crown  104  as illustrated by  FIG. 2 . Thus, in some implementations of the present invention, the width  114  of each notch  112  at the outer surface  108  of the crown  104  can be approximately equal to the width  116  of each notch  112  at the inner surface  107  of the crown  104 . In other words, the circumferential distance  114  between the first side surface  112   a  and the second side surface  112   b  of each notch  112  at the outer surface  108  can be approximately equal to the circumferential distance  116  between the first side surface  112   a  and the second side surface  112   b  of each notch  112  at the inner surface  107 . In alternative implementations of the present invention, as explained in greater detail below, one or more of the side surfaces  112   a ,  112   b  may include a radial and/or a circumferential taper. 
     Thus, the notches  112  can have any shape that allows them to operate as intended. In particular, the shape and configuration of the notches  112  can be altered depending upon the characteristics desired for the drill bit  100  or the characteristics of the formation to be drilled. For example, the  FIG. 2  illustrates that the notches can have a rectangular shape when viewed from cutting face  109 . In alternative implementation, however, the notches can have square, triangular, circular, trapezoidal, polygonal, elliptical shape or any combination thereof. 
     Furthermore, the notches  112  may have any width or length that allows them to operate as intended. For example,  FIG. 2  illustrates that the notches  112  can have a length (i.e., distance from the inside surface  107  to the outside surface  108 ) that is greater than their width (i.e., distance between opposing side surfaces  112   a  and  112   b ). In alternative implementations of the present invention, however, the notches  112  can have a width greater than their length, or a width that is approximately equal to their length. 
     In addition, the individual notches  112  in the crown  104  can be configured uniformly with the same size and shape, or alternatively with different sizes and shapes. For example,  FIGS. 1-3  illustrate all of the notches  112  in the crown  104  have the same size and configuration. In additional implementation, however, the various notches  112  of the crown  104  can include different sizes and configurations. For example, in some implementations the drill bit  100  can include two different sizes of notches  112  that alternate around the circumference of the crown  104 . 
     As mentioned previously, the waterways (i.e., notches  112 ) can be axially tapered. In particular, as shown by  FIG. 3 , the top surface  112   c  of each notch  112  can taper from the inner surface  107  to the outer surface  108  in a direction generally from the cutting face  109  toward the shank  102 . In other words, the height or longitudinal dimension of each notch  112  can increase as the notch  112  extends from the inner surface  107  to the outer surface  108  of the crown  104 . Thus, as shown by  FIG. 3 , in some implementations the longitudinal dimension  124  of each notch  112  at the outer surface  108  can be greater than the longitudinal dimension  120  of each notch  112  at the inner surface  107 . In other words, each notch  112  can extend into the cutting face  109  a first distance  120  at the inner surface  107  and extend into the cutting face  109  a second distance  124  at the outer surface  120 , where the second distance  124  is greater than the first distance  120 . 
     One will appreciate in light of the disclosure herein that the axial-taper of the notches  112  can help ensure that the opening of each notch  112  at the inner surface  107  is smaller than the opening of each notch  112  at the outer surface  108  of the crown  104 . This difference in opening sizes can increase the velocity of drilling fluid at the inside surface  107  as it passes to the outside surface  108  of the crown  104 . Thus, as explained above, the axial-taper of the notches  112  can provide for more efficient flushing of cuttings and cooling of the cutting face  109 . Furthermore, the increasing size of the notches  112  can also help ensure that debris does not jam or clog in the notch  112  as drilling fluid forces it from the inner surface  107  to the outer surface  108 . 
     Additionally, as shown by  FIGS. 2 and 3 , the axial-taper of the notches  112  can provide the notches  112  with increasing size without reducing the size of the cutting face  109 . One will appreciate that in one or more implementations of the present invention, an increased surface area of the cutting face  109  can provide for more efficient drilling. Furthermore, the axial-taper of the notches  112  can provide for increased flushing and cooling, while also not decreasing the volume of crown material at the inside surface  107 . The increased volume of crown material at the inside surface  107  can help increase the drilling life of the drill bit  100 . 
     In addition to notches  112 , the crown  104  can include additional features that can further aid in directing drilling fluid or other lubricants to the cutting face  109  or from the inside surface  107  to the outside surface  108  of the crown  104 . For example,  FIGS. 1-3  illustrate that the drill bit  110  can include a plurality of flutes  122 ,  124  extending radially into the crown  104 . In particular, in some implementations of the present invention the drill bit  100  can include a plurality of inner flutes  122  that extend radially from the inner surface  107  toward the outer surface  108 . The plurality of inner flutes  122  can help direct drilling fluid along the inner surface  107  of the drill bit  100  from the shank  102  toward the cutting face  109 . As shown in  FIG. 1-3 , in some implementations of the present invention the inner flutes  122  can extend from the shank  102  axially along the inner surface  107  of the crown  104  to the notches  112 . Thus, the inner flutes  122  can help direct drilling fluid to the notches  112 . In alternative implementations, the inner flutes  122  can extend from the shank  102  to the cutting face  109 , or even along the shank  102 . 
       FIGS. 1-3  additionally illustrate that in some implementations, the drill bit  100  can include a plurality of outer flutes  124 . The outer flutes  124  can extend radially from the outer surface  108  toward the inner surface  107  of the crown  104 . The plurality of outer flutes  124  can help direct drilling fluid along the outer surface  108  of the drill bit  100  from the notches  112  toward the shank  102 . As shown in  FIGS. 1-3 , in some implementations of the present invention the outer flutes  124  can extend from the notches  112  axially along the outer surface  108  to the shank  102 . In alternative implementations, the outer flutes  124  can extend from the cutting face  109  to the shank  102 , or even along the shank  102 . 
     As mentioned previously, one or more implementations of the present invention can include double-tapered waterways. For example,  FIGS. 4-6  illustrate various view of a drilling tool  200  including double-tapered waterways. In particular,  FIG. 4  illustrates a perspective view,  FIG. 5  illustrates a bottom view, and  FIG. 6  illustrates a partial cross-sectional view of a core-sampling drill bit  200  having double-taped notches. Similar to the drill bit  100 , the drill bit  200  can include a shank  202  and a crown  204 . 
     The crown  204  can have a generally annular shape defined by an inner surface  207  and an outer surface  208 . The crown  204  can additionally extend from the shank  202  and terminate in a cutting face  209 . As shown by  FIG. 4 , in some implementations of the present invention, the cutting face  209  may extend from the inner surface  207  to the outer surface  208  in a direction generally normal to the longitudinal axis  206  of the drill bit  200 . In some implementations, the cutting face  209  can include a plurality of grooves  210 . The crown  204  can further include a plurality of double-tapered waterways  212  as explained in greater detail below. 
     As mentioned previously, the drill bit  200  can include double-tapered waterways. For example,  FIG. 5  illustrates that each of the notches  212  can include a radial taper in addition to an axial taper. More specifically, each notch  212  can be defined by at least three surfaces  212   a ,  212   b ,  212   c . In particular, each notch  212  can be defined by a first side surface  212   a , an opposing side surface  212   b , and a top surface  212   c . In some implementations of the present invention, the first sides surface  212   a  can extend from the inner surface  207  of the crown  204  to the outer surface  208  of the crown  204  in a direction generally normal to the inner surface of the crown  204  as illustrated by  FIG. 5 . 
     As mentioned previously, the waterways (i.e., notches  212 ) can be radially tapered. In particular, as shown by  FIG. 5 , the second side surface  212   b  of each notch  212  can taper from the inner surface  207  to the outer surface  208  in a direction generally clockwise around the circumference of the cutting face  209 . As used herein, the terms “clockwise” and “counterclockwise” refer to directions relative to the longitudinal axis of a drill bit when viewing the cutting face of the drill bit. Thus, the width of each notch  212  can increase as the notch  212  extends from the inner surface  207  to the outer surface  208  of the crown  204 . Thus, as shown by  FIG. 5 , in some implementations the width  214  of each notch  212  at the outer surface  208  can be greater than the width  216  of each notch  212  at the inner surface  207 . In other words, the circumferential distance  214  between the first side surface  212   a  and the second side surface  212   b  of each notch  212  at the outer surface  208  can be greater than the circumferential distance  216  between the first side surface  212   a  and the second side surface  212   b  of each notch  212  at the inner surface  207 . 
     One will appreciate in light of the disclosure herein that the radial taper of the notches  212  can ensure that the opening of each notch  212  at the inner surface  207  is smaller than the opening of each notch  212  at the outer surface  208  of the crown  204 . This difference in opening sizes can increase the velocity of drilling fluid at the inside surface  207  as it passes to the outside surface  208  of the crown  204 . Thus, as explained above, the radial taper of the notches  212  can provide for more efficient flushing of cuttings and cooling of the cutting face  209 . Furthermore, the increasing width of the notches  212  can also help ensure that debris does not jam or clog in the notch  212  as drilling fluid forces it from the inner surface  207  to the outer surface  208 . 
       FIGS. 4-6  illustrate that the radial taper of the notches  212  can be formed by a tapered second side surface  212   b . One will appreciate that alternatively the first side surface  212   a  can include a taper. For example, the first side surface  212   a  can taper from the inner surface  207  to the outer surface  208  in a direction generally counter-clockwise around the circumference of the cutting face  209 . Additionally, in some implementation the first side surface  212   a  and the second side surface  212   b  can both include a taper extending from the inner surface  207  to the outer surface  208  in a direction generally clockwise around the circumference of the cutting face  209 . In such implementations, the radial taper of the second side surface  212   b  can have a larger taper than the first side surface  212   a  in a manner that the width of the notch  212  increases as the notch  212  extends from the inner surface  207  to the outer surface  208 . 
     As mentioned previously, the waterways (i.e., notches  212 ) can be axially tapered in addition to being radially tapered. In particular, as shown by  FIG. 6 , the top surface  212   c  of each notch  212  can taper from the inner surface  207  to the outer surface  208  in a direction generally from the cutting face  209  toward the shank  202 . In other words, the longitudinal dimension of each notch  212  can increase as the notch  212  extends from the inner surface  207  to the outer surface  208  of the crown  204 . Thus, as shown by  FIG. 6 , in some implementations the longitudinal dimension  224  of each notch  212  at the outer surface  208  can be greater than the longitudinal dimension  220  of each notch  212  at the inner surface  207 . In other words, each notch  212  can extend into the cutting face  209  a first distance  220  at the inner surface  207  and extend into the cutting face  209  a second distance  224  at the outer surface  208 , where the second distance  224  is greater than the first distance  220 . 
     One will appreciate in light of the disclosure herein that the axial taper of the notches  212  can help ensure that the opening of each notch  212  at the inner surface  207  is smaller than the opening of each notch  212  at the outer surface  208  of the crown  204 . This difference in opening sizes can increase the velocity of drilling fluid at the inside surface  207  as it passes to the outside surface  208  of the crown  204 . Thus, as explained above, the axial-taper of the notches  212  can provide for more efficient flushing of cuttings and cooling of the cutting face  209 . Furthermore, the increasing size of the notches  212  can also help ensure that debris does not jam or clog in the notch  212  as drilling fluid forces it from the inner surface  207  to the outer surface  208 . 
     One will appreciate in light of the disclosure therein that the double-tapered notches  212  can ensure that the notches  212  increase in dimension in each axis (i.e., both radially and axially) as they extend from the inner surface  207  of the drill bit  200  to the outer surface  208 . The increasing size of the double-tapered notches  212  can reduce the likelihood of debris lodging within the notches  212 , and thus, increase the drilling performance of the drill bit  200 . Furthermore, as previously discussed the increasing size of the double-tapered notches  212  can help maximize the volume of matrix material at the inner surface  107 , and thereby can increase the life of the drill bit  200  by reducing premature drill bit wear at the inner surface  207 . 
     In addition to the waterways, the crown  204  can include a plurality of flutes for directing drilling fluid, similar to the flutes described herein above in relation to the drill bit  100 . For example, in some implementations of the present invention the drill bit  200  can include a plurality of inner flutes  222  that can extend radially from the inner surface  207  toward the outer surface  208 . The plurality of inner flutes  222  can help direct drilling fluid along the inner surface  207  of the drill bit  200  from the shank  202  toward the cutting face  209 . As shown in  FIG. 4-6 , in some implementations of the present invention the inner flutes  222  can extend from the shank  202  axially along the inner surface  207  to the notches  212 . Thus, the inner flutes  222  can help direct drilling fluid to the notches  212 . 
     Additionally, the crown  204  can include full inner flutes  222   a . As shown in  FIG. 4 , the full inner flutes  222   a  can extend from the shank  202  to the cutting face  209  without intersecting a notch  212 . Along similar lines, the drill bit  200  can include outer flutes  224  and full outer flutes  224   a . The outer flutes  224  can extend from the shank  202  to a notch  212 , while the full outer flutes  224   a  can extend from the shank  202  to the cutting face  209  without intersecting a notch  212 . In alternative implementations, the full inner flutes  222   a  and/or the full outer flutes  224   a  can extend from the shank  202  to the cutting face  209  and also run along the a side surface  212   a ,  212   b  of a notch  212 . 
     As mentioned previously, in one or more implementations of the present invention the waterways of the drilling tools can include a radial taper. For example,  FIGS. 4-6  illustrate notches  212  having a second side surface  212   b  including a radial taper. Alternatively, both side surfaces can include a radial taper. For example,  FIG. 7  illustrates a bottom view of a core-sampling drill bit  300  including double-tapered notches  312  where both of the side surfaces  312   a ,  312   b  include a radial taper. 
     Similar to the other drill bits described herein above, the drill bit  300  can include a shank  302  and a crown  304 . The crown  304  can have a generally annular shape defined by an inner surface  307  and an outer surface  308 . The crown  304  can thus define a space about a central axis  306  for receiving a core sample. The crown  304  can additionally extend from the shank  302  and terminate in a cutting face  309 . The cutting face  309  can include a plurality of grooves  310  extending therein. Additionally, the drill bit  300  can include inner flutes  322  and outer flutes  324  for directing drilling fluid about the drill bit  300 . 
     Furthermore, as shown by  FIG. 7 , the second side surface  312   b  of each notch  312  can taper from the inner surface  307  to the outer surface  308  of the crown  304  in a direction generally clockwise around the circumference of the cutting face  309 . Additionally, the first side surface  312   a  of each notch  312  can taper from the inner surface  307  to the outer surface  308  of the crown  304  in a direction generally counter-clockwise around the circumference of the cutting face  309 . Thus, the width of each notch  312  can increase as the notch  312  extends from the inner surface  307  to the outer surface  308  of the crown  304 . 
     Thus, as shown by  FIG. 7 , in some implementations the width  314  of each notch  312  at the outer surface  308  can be greater than the width  316  of each notch  312  at the inner surface  307 . In other words, the circumferential distance  314  between the first side surface  312   a  and the second side surface  312   b  of each notch  312  at the outer surface  308  can be greater than the circumferential distance  316  between the first side surface  312   a  and the second side surface  312   b  of each notch  312  at the inner surface  307 . 
     Each of the axially-tapered waterways described herein above have been notches extending into a cutting face of a crown. One will appreciate in light of the disclosure herein that the present invention can include various other or additional waterways having an axial taper. For instance, the drilling tools of one or more implementations of the present invention can include one or more enclosed fluid slots having an axial taper, such as the enclosed fluid slots described in U.S. patent application Ser. No. 11/610,680, filed Dec. 14, 2006, entitled “Core Drill Bit with Extended Crown Longitudinal dimension,” the content of which is hereby incorporated herein by reference in its entirety. 
     For example,  FIGS. 8-10  illustrate various views of a core-sampling drill bit  400  that includes both axially-taper notches and axially-tapered enclosed slots. Similar to the other drill bits described herein above, the drill bit  400  can include a shank  402  and a crown  404 . The crown  404  can have a generally annular shape defined by an inner surface  407  and an outer surface  408 . The crown  404  can additionally extend from the shank  402  and terminate in a cutting face  409 . In some implementations, the cutting face  409  can include a plurality of grooves  410  extending therein as shown in  FIGS. 8-10 . 
     As shown in  FIG. 8  the drill bit  400  can include double-tapered notches  412  similar in configuration to double-taped notches  212  described above in relation to  FIGS. 4-6 . Thus, notches  412  can a top surface  412   c  that can taper from the inner surface  407  to the outer surface  408  in a direction generally from the cutting face  409  toward the shank  402 . Additionally, a first side surface  412   a  of each notch  412  can extend from the inner surface  407  of the crown  404  to the outer surface  408  of the crown  404  in a direction generally normal to the inner surface of the crown  404 . Furthermore, a second side surface  412   b  of each notch  412  can taper from the inner surface  407  to the outer surface  408  in a direction generally clockwise around the circumference of the cutting face  409 . 
     In addition to the double-tapered notches  412 , the drill bit can include a plurality of enclosed slots  430 . The enclosed slots  430  can include an axial and/or a radial taper as explained in greater detail below. One will appreciate that as the crown  404  erodes through drilling, the notches  412  can wear away. As the erosion progresses, the enclosed slots  430  can become exposed at the cutting face  409  and then thus become notches. One will appreciate that the configuration of drill bit  400  can thus allow the longitudinal dimension of the crown  404  to be extended and lengthened without substantially reducing the structural integrity of the drill bit  400 . The extended longitudinal dimension of the crown  404  can in turn allow the drill bit  400  to last longer and require less tripping in and out of the borehole to replace the drill bit  400 . 
     In particular,  FIG. 8  illustrates that the crown  404  can include a plurality of enclosed slots  430  that extend a distance from the cutting face  409  toward the shank  402  of the drill bit  400 . Additionally, the enclosed slots  430  can extend from the inner surface  407  of the crown  404  to the outer surface  408  of the crown  404 . As waterways, the enclosed slots  430  can allow drilling fluid to flow from the inner surface  407  of the crown  404  to the outer surface  408  of the crown  404 . Thus, the enclosed slots  430  can allow drilling fluid to flush cuttings and debris from the inner surface  407  to the outer surface  408  of the drill bit  400 , and also provide cooling to the cutting face  409 . 
     The crown  404  may have any number of enclosed slots  430  that provides the desired amount of fluid/debris flow or crown longitudinal dimension, while also allowing the crown  404  to maintain the structural integrity needed. For example,  FIGS. 8 and 10  illustrate that the drill bit  400  can include six enclosed slots  430 . One will appreciate in light of the disclosure herein that the present invention is not so limited. In additional implementations, the drill bit  400  can include as few as one enclosed slot or as many 20 or more enclosed slots, depending on the desired configuration and the formation to be drilled. Additionally, the enclosed slots  430  may be evenly or unevenly spaced around the circumference of the crown  404 . For example,  FIGS. 8-10  depict enclosed slots  430  evenly spaced from each other about the circumference of the crown  404 . In alternative implementations, however, the enclosed slots  430  can be staggered or otherwise not evenly spaced. 
     As shown in  FIG. 8 , each enclosed slot  430  can be defined by four surfaces  430   a ,  430   b ,  430   c ,  430   d . In particular, each enclosed slot  430  can be defined by a first side surface  430   a , an opposing side surface  430   b , a top surface  430   c , and an opposing bottom surface  430   d . In some implementations of the present invention, each of the sides surfaces  430   a ,  430   b  can extend from the inner surface  407  of the crown  404  to the outer surface  408  of the crown  404  in a direction generally normal to the inner surface of the crown  404 . In alternative implementations of the present invention, as explained in greater detail below, one or more of the side surfaces  430   a ,  430   b  may include a radial and/or a circumferential taper. 
     Thus, the enclosed slots  430  can have any shape that allows them to operate as intended, and the shape can be altered depending upon the characteristics desired for the drill bit  400  or the characteristics of the formation to be drilled. For example, the  FIG. 9  illustrates that the enclosed slots can have a trapezoidal shape. In alternative implementation, however, the enclosed slots  430  can have square, triangular, circular, rectangular, polygonal, or elliptical shapes, or any combination thereof. 
     Furthermore, the enclosed slots  430  may have any width or length that allows them to operate as intended. For example,  FIG. 9  illustrates that the enclosed slots  430  have a length (i.e., distance from the inside surface  407  to the outside surface  408 ) that is greater than their width (i.e., distance between opposing side surfaces  430   a  and  430   b ). In addition, the individual enclosed slots  430  in the crown  404  can be configured uniformly with the same size and shape, or alternatively with different sizes and shapes. For example,  FIGS. 8-10  illustrate all of the enclosed slots  430  in the crown  404  can have the same size and configuration. In additional implementation, however, the various enclosed slots  430  of the crown  404  can include different sizes and configurations. 
     Furthermore, the crown  404  can include various rows of waterways. For example,  FIG. 8  illustrates that the crown  404  can include a row of notches  412  that extend a first distance  432  from the cutting face  409  into the crown  404 . Additionally,  FIG. 8  illustrates that the crown  404  can include a first row of enclosed slots  430  commencing in the crown  404  a second distance  434  from the cutting face  409 , and a second row of enclosed slots  430  commencing in the crown  404  a third distance  436  from the cutting face  409 . In alternative implementations of the present invention, the crown  404  can include a single row of enclosed slots  430  or multiple rows of enclosed slots  430  each axially staggered from the other. 
     In some instances, a portion of the notches  412  can axially overlap the first row of enclosed slots  430 . In other words, the first distance  432  can be greater than the second distance  434 . Along similar lines, a portion of the enclosed slots  430  in the first row can axially overlap the enclosed slots in the second row. One will appreciate in light of the disclosure herein that the axially overlap of the waterways  412 ,  430  can help ensure that before notches  412  have completely eroded away during drilling, the first row of enclosed slots  430  will open to become notches  412 , allowing the drill bit  400  to continue to cut efficiently as the drill bit  400  erodes. 
     Additionally, as  FIG. 8  illustrates, the enclosed slots  430  in the first row can be circumferentially offset from the notches  412 . Similarly, the enclosed slots  430  in the second row can be circumferentially offset from the enclosed slots  430  in the first row and the notches  412 . In alternative implementations, one or more of the enclosed slots  430  in the first and second row can be circumferentially aligned with each other or the notches  412 . 
     As mentioned previously, in one or more implementations the enclosed slots  430  can include a double-taper. For example,  FIG. 9  illustrates that each of the enclosed slots  430  can include a radial taper. In some implementations of the present invention, the first side surface  430   a  can extend from the inner surface  407  of the crown  404  to the outer surface  408  of the crown  404  in a direction generally normal to the inner surface  407  of the crown  404  as illustrated by  FIG. 9 . 
     Furthermore, the second side surface  430   b  of each enclosed slot  430  can taper from the inner surface  407  to the outer surface  408  in a direction generally clockwise around the circumference of the crown  404 . In other words, the width of each enclosed slot  430  can increase as the enclosed slot  430  extends from the inner surface  407  to the outer surface  408  of the crown  404 . Thus, as shown by  FIG. 9 , in some implementations the width  414  of each enclosed slot  430  at the outer surface  408  can be greater than the width  416  of each enclosed slot  430  at the inner surface  407 . In other words, the circumferential distance  414  between the first side surface  430   a  and the second side surface  430   b  of each enclosed slot  430  at the outer surface  408  can be greater than the circumferential distance  416  between the first side surface  430   a  and the second side surface  430   b  of each enclosed slot  430  at the inner surface  407 . 
     One will appreciate in light of the disclosure herein that the radial taper of the enclosed slots  430  can ensure that the opening of each enclosed slot  430  at the inner surface  407  is smaller than the opening of each enclosed slot  430  at the outer surface  408  of the crown  404 . This difference in opening sizes can increase the velocity of drilling fluid at the inside surface  407  as it passes to the outside surface  408  of the crown  404 . Thus, as explained above, the radial-taper of the enclosed slots  430  can provide for more efficient flushing of cuttings and cooling of the drill bit  400 . Furthermore, the increasing width of the enclosed slots  430  can also help ensure that debris does not jam or clog in the enclosed slot  430  as drilling fluid forces it from the inner surface  407  to the outer surface  408 . 
       FIGS. 8-10  also illustrate that the radial taper of the enclosed slots  430  can be formed by a tapered second side surface  430   b . One will appreciate that in alternatively, or additionally, the first side surface  430   a  can include a taper. For example, the first side surface  430   a  can taper from the inner surface  407  to the outer surface  408  in a direction generally counter-clockwise around the circumference of the crown  404 . 
     As mentioned previously, the waterways (i.e., enclosed slots  430 ) can be axially tapered in addition to being radially tapered. In particular, as shown by  FIG. 10 , the top surface  430   c  of each enclosed slot  430  can taper from the inner surface  407  to the outer surface  408  in a direction generally from the cutting face  409  toward the shank  402 . In other words, the longitudinal dimension of each enclosed slot  430  can increase as the enclosed slot  430  extends from the inner surface  407  to the outer surface  408  of the crown  404 . Thus, as shown by  FIG. 10 , in some implementations the longitudinal dimension  444  of each enclosed slot  430  at the outer surface  408  can be greater than the longitudinal dimension  442  of each enclosed slot  430  at the inner surface  407 . Or in other words, the top surface  430   c  of each enclosed slot  430  at the outer surface  408  can be farther from the cutting face  409  than the top surface  430   c  of each enclosed slot  430  at the inner surface  407 . 
     Alternatively, or additionally, the bottom surface  430   d  of each enclosed slot  430  can taper from the inner surface  407  to the outer surface  408  in a direction generally from the shank  402  toward the cutting face  409 . In other words, the longitudinal dimension of each enclosed slot  430  can increase as the enclosed slot  430  extends from the inner surface  407  to the outer surface  408  of the crown  404 . Or in other words, the bottom surface  430   d  of each enclosed slot  430  at the outer surface  408  can be closer to the cutting face  409  than the bottom surface  430   d  of each enclosed slot  430  at the inner surface  407 . Thus, in some implementations the enclosed slots  430  can include a double-axial taper where both the top surface  430   c  and the bottom surface  430   d  include a taper. 
     One will appreciate in light of the disclosure herein that the axial-taper of the enclosed slots  430  can ensure that the opening of each enclosed slot  430  at the inner surface  407  is smaller than the opening of each enclosed slot  430  at the outer surface  408  of the crown  404 . This difference in opening sizes can increase the velocity of drilling fluid at the inside surface  407  as it passes to the outside surface  408  of the crown. Thus, as explained above, the axial-taper of the enclosed slots  430  can provide for more efficient flushing of cuttings and cooling of the drill bit  404 . Furthermore, the increasing size of the enclosed slots  430  can also help ensure that debris does not jam or clog in the enclosed slots  430  as drilling fluid forces it from the inner surface  407  to the outer surface  408 . 
     One will appreciate in light of the disclosure therein that the double-subtapered enclosed slots  430  can ensure that the enclosed slots  430  increase in dimension in each axis as they extend from the inner surface  407  of the drill bit  400  to the outer surface  408 . The increasing size of the double-tapered enclosed slots  430  can reduce the likelihood of debris lodging within the enclosed slots  430 , and thus, increase the drilling performance of the drill bit  400 . Furthermore, the double-tapered enclosed slots  430  can provide efficient flushing while also reducing the removal of material at the inner surface  407  of the drill bit  400 . Thus, the double-tapered enclosed slots  430  can help increase the drilling life of the drill bit by helping to reduce premature wear of the drill bit  400  near the inner surface  407 . 
       FIGS. 8-10  further illustrate that the corners of the waterways  412 ,  430  can include a rounded surface or chamfer. The rounded surface of the corners of the waterways  412 ,  430  can help reduce the concentration of stresses, and thus can help increase the strength of the drill bit  400 . 
     In addition to the waterways, the crown  404  can include a plurality of flutes for directing drilling fluid, similar to the flutes described herein above in relation to the drill bit  200 . For example, in some implementations of the present invention the drill bit  400  can include a plurality of inner flutes  422  that extend radially from the inner surface  407  toward the outer surface  408 . The plurality of inner flutes  422  can help direct drilling fluid along the inner surface  407  of the drill bit  400  from the shank  402  toward the cutting face  409 . As shown in  FIG. 8-10 , in some implementations of the present invention the inner flutes  422  can extend from the shank  402  axially along the inner surface  407  to the notches  412 . Thus, the inner flutes  422  can help direct drilling fluid to the notches  412 . 
     Additionally, the crown  404  can include full inner flutes  422   b  that intersect an enclosed slot  430 . As shown in  FIG. 10 , the full inner flutes  422   b  can extend from the shank  402  to the cutting face  409 . In some implementations of the present invention, the full inner flutes  422   b  can intersect one or more enclosed slots  430  as illustrated by  FIG. 10 . Along similar lines, the drill bit  400  can include outer flutes  424  and full outer flutes  424   a . The outer flutes  424  can extend from the shank  402  to a notch  412 , while the full outer flutes  424   a  can extend from the shank  402  to the cutting face  409  while also intersecting an enclosed slot  430 . 
     In addition to the waterways  412 ,  430  and flutes  422 ,  424 , the drill bit  400  can further includes enclosed fluid channels  440 . The enclosed fluid channels  440  can be enclosed within the drill bit  400  between the inner surface  407  and the outer surface  408 . Furthermore, as shown in  FIG. 10 , the enclosed fluid channels  440  can extend from the shank  402  to a waterway  412 ,  430 , or to the cutting face  409 . The enclosed fluid channels  440  can thus direct drilling fluid to the cutting face  409  without having to flow across the inner surface  407  of the crown  404 . One will appreciate in light of the disclosure herein that when drilling in sandy, broken, or fragmented formations, the enclosed fluid channels  440  can help ensure that a core sample is not flushed out of the drill bit  400  by the drilling fluid. 
     Some implementations of the present invention can include additional or alternative features to the enclosed fluid channels  440  that can help prevent washing away of a core sample. For example, in some implementations the drill bit  400  can include a thin wall along the inner surface  407  of the crown  404 . The thin wall can close off the waterways  412 ,  430  so they do not extend radially to the interior of the crown  404 . The thin wall can help reduce any fluid flowing to the interior of the crown  404 , and thus, help prevent a sandy or fragmented core sample from washing away. Furthermore, the drill bit  400  may not include inner flutes  422 . One will appreciate in light of the disclosure herein that in such implementations, drilling fluid can flow into the enclosed fluid channels  440 , axially within the crown  404  to a waterway  412 ,  430 , and then out of the waterway  412 ,  430  to the cutting face  409  or outer surface  408 . 
     As mentioned previously, the shanks  102 ,  202 ,  302 ,  402  of the various drilling tools of the present invention can be configured to secure the drill bit to a drill string component. For example, the shank  102 ,  202 ,  302 ,  402  can include an American Petroleum Institute (API) threaded connection portion or other features to aid in attachment to a drill string component. By way of example and not limitation, the shank portion  102 ,  202 ,  302 ,  402  may be formed from steel, another iron-based alloy, or any other material that exhibits acceptable physical properties. 
     In some implementations of the present invention, the crown  104 ,  204 ,  304 ,  404  of the drill tools of the present invention can be made of one or more layers. For example, according to some implementations of the present invention, the crown  104 ,  204 ,  304 ,  404  can include two layers. In particular, the crown  104 ,  204 ,  304 ,  404  can include a matrix layer, which performs the drilling operation, and a backing layer, which connects the matrix layer to the shank  102 ,  202 ,  302 ,  402 . In these implementations, the matrix layer can contain the abrasive cutting media that abrades and erodes the material being drilled. 
     In some implementations, the crown  104 ,  204 ,  304 ,  404  can be formed from a matrix of hard particulate material, such as for example, a metal. One will appreciate in light of the disclosure herein, that the hard particular material may include a powered material, such as for example, a powered metal or alloy, as well as ceramic compounds. According to some implementations of the present invention the hard particulate material can include tungsten carbide. As used herein, the term “tungsten carbide” means any material composition that contains chemical compounds of tungsten and carbon, such as, for example, WC, W2C, and combinations of WC and W2C. Thus, tungsten carbide includes, for example, cast tungsten carbide, sintered tungsten carbide, and macrocrystalline tungsten. According to additional or alternative implementations of the present invention, the hard particulate material can include carbide, tungsten, iron, cobalt, and/or molybdenum and carbides, borides, alloys thereof, or any other suitable material. 
     As mentioned previously, the crown  104 ,  204 ,  304 ,  404  can also include a plurality of abrasive cutting media dispersed throughout the hard particulate material. The abrasive cutting media can include one or more of natural diamonds, synthetic diamonds, polycrystalline diamond or thermally stable diamond products, aluminum oxide, silicon carbide, silicon nitride, tungsten carbide, cubic boron nitride, alumina, seeded or unseeded sol-gel alumina, or other suitable materials. 
     The abrasive cutting media used in the drilling tools of one or more implementations of the present invention can have any desired characteristic or combination of characteristics. For instance, the abrasive cutting media can be of any size, shape, grain, quality, grit, concentration, etc. In some embodiments, the abrasive cutting media can be very small and substantially round in order to leave a smooth finish on the material being cut by the core-sampling drill bit  100 ,  200 ,  300 ,  400 . In other embodiments, the cutting media can be larger to cut aggressively into the material or formation being drill. 
     The abrasive cutting media can be dispersed homogeneously or heterogeneously throughout the crown  104 ,  204 ,  304 ,  404 . As well, the abrasive cutting media can be aligned in a particular manner so that the drilling properties of the media are presented in an advantageous position with respect to the crown  104 ,  204 ,  304 ,  404 . Similarly, the abrasive cutting media can be contained in the crown  104 ,  204 ,  304 ,  404  in a variety of densities as desired for a particular use. For example, large abrasive cutting media spaced further apart can cut material more quickly than small abrasive cutting media packed tightly together. Thus, one will appreciate in light of the disclosure herein that the size, density, and shape of the abrasive cutting media can be provided in a variety of combinations depending on desired cost and performance of the drill bit  100 ,  200 ,  300 ,  400 . 
     For example, the crown  104 ,  204 ,  304 ,  404  may be manufactured to any desired specification or given any desired characteristic(s). In this way, the crown  104 ,  204 ,  304 ,  404  may be custom-engineered to possess optimal characteristics for drilling specific materials. For example, a hard, abrasion resistant matrix may be made to drill soft, abrasive, unconsolidated formations, while a soft ductile matrix may be made to drill an extremely hard, non-abrasive, consolidated formation. In this way, the matrix hardness may be matched to particular formations, allowing the matrix layer to erode at a controlled, desired rate. 
     One will appreciate that the drilling tools with a tailored cutting portion according to implementations of the present invention can be used with almost any type of drilling system to perform various drilling operations. For example,  FIG. 11 , and the corresponding text, illustrate or describe one such drilling system with which drilling tools of the present invention can be used. One will appreciate, however, the drilling system shown and described in  FIG. 11  is only one example of a system with which drilling tools of the present invention can be used. 
     For example,  FIG. 11  illustrates a drilling system  500  that includes a drill head  510 . The drill head  510  can be coupled to a mast  520  that in turn is coupled to a drill rig  530 . The drill head  510  can be configured to have one or more tubular members  540  coupled thereto. Tubular members can include, without limitation, drill rods, casings, and down-the-hole hammers. For ease of reference, the tubular members  540  will be described herein after as drill string components. The drill string component  540  can in turn be coupled to additional drill string components  540  to form a drill or tool string  550 . In turn, the drill string  550  can be coupled to drilling tool  560  including axially-tapered waterways, such as the core-sampling drill bits  100 ,  200 ,  300 ,  400  described hereinabove. As alluded to previously, the drilling tool  560  can be configured to interface with the material  570 , or formation, to be drilled. 
     In at least one example, the drill head  510  illustrated in  FIG. 11  can be configured rotate the drill string  550  during a drilling process. In particular, the drill head  510  can vary the speed at which the drill head  510  rotates. For instance, the rotational rate of the drill head and/or the torque the drill head  510  transmits to the drill string  550  can be selected as desired according to the drilling process. 
     Furthermore, the drilling system  500  can be configured to apply a generally longitudinal downward force to the drill string  550  to urge the drilling tool  560  into the formation  570  during a drilling operation. For example, the drilling system  500  can include a chain-drive assembly that is configured to move a sled assembly relative to the mast  520  to apply the generally longitudinal force to the drilling tool bit  560  as described above. 
     As used herein the term “longitudinal” means along the length of the drill string  550 . Additionally, as used herein the terms “upper,” “top,” and “above” and “lower” and “below” refer to longitudinal positions on the drill string  550 . The terms “upper,” “top,” and “above” refer to positions nearer the drill head  510  and “lower” and “below” refer to positions nearer the drilling tool  560 . 
     Thus, one will appreciate in light of the disclosure herein, that the drilling tools of the present invention can be used for any purpose known in the art. For example, a diamond-impregnated core sampling drill bit  100 ,  200 ,  300 ,  400  can be attached to the end of the drill string  550 , which is in turn connected to a drilling machine or rig  530 . As the drill string  550  and therefore the drill bit  560  are rotated and pushed by the drilling machine  530 , the drill bit  560  can grind away the materials in the subterranean formations  570  that are being drilled. The core samples that are drilled away can be withdrawn from the drill string  550 . The cutting portion of the drill bit  560  can erode over time because of the grinding action. This process can continue until the cutting portion of a drill bit  560  has been consumed and the drilling string  550  can then be tripped out of the borehole and the drill bit  560  replaced. 
     Implementations of the present invention also include methods of forming drilling tools having axially-tapered waterways. The following describes at least one method of forming drilling tools having axially-tapered waterways. Of course, as a preliminary matter, one of ordinary skill in the art will recognize that the methods explained in detail can be modified to install a wide variety of configurations using one or more components of the present invention. 
     As an initial matter, the term “infiltration” or “infiltrating” as used herein involves melting a binder material and causing the molten binder to penetrate into and fill the spaces or pores of a matrix. Upon cooling, the binder can solidify, binding the particles of the matrix together. The term “sintering” as used herein means the removal of at least a portion of the pores between the particles (which can be accompanied by shrinkage) combined with coalescence and bonding between adjacent particles. 
     One or more of the methods of the present invention can include using plugs to form the axially-tapered waterways in a drilling tool. For example,  FIGS. 12-14  illustrate various views of a plug  600  that can be used to form an axially-tapered waterway, such as the notches  212  of drill bit  200  or slots  430  of drill bit  400 . As shown by  FIGS. 12-14 , the plug  600  can include surfaces corresponding to the surfaces of an axially-tapered waterway. For example, the plug  600  can include a top surface  602 , a bottom surface  604 , a first side surface  608 , and a second side surface  606 . Additionally, the plug  600  can include chamfers  610  connecting the surfaces  602 ,  604 ,  606 ,  608  of the plug  600 . 
     As shown by  FIG. 13 , the top surface  602  of the plug  600  can include a taper such that a first end of the plug  600  can have a first longitudinal dimension  612  and a second end of the plug  600  can have a second longitudinal dimension  614  that is greater than the first longitudinal dimension  612 . Thus, as explained in greater detail below the taper of the top surface  602  can help form the axial taper of a waterway. 
     Along similar lines,  FIG. 14  illustrates that the second side surface  606  can include a taper such that the first end of the plug  600  can have a first width  616  and the second end of the plug  600  can have a second width  618  that is greater than the first width  616 . Thus, as explained in greater detail below the taper of the second side surface  606  can help form the radial taper of a waterway. One will appreciate that the shape and configuration of the plug  600  can vary depending upon the desired shape and configuration of a waterway to be formed with the plug  600 . 
     In some implementations of the present invention the plug  600  can be formed from graphite, carbon, or other material with suitable material characteristics. For example, the plug  600  can be formed from a material which will not significantly melt or decay during infiltration or sintering. As explained in greater detail below, by using a plug  600  formed from a material that does not significantly melt, the plug  600  can be relatively easily removed from an infiltrated drilling tool. 
     One method of the present invention can include providing a matrix of hard particulate material and abrasive cutting media, such as the previously described hard particulate materials and abrasive cutting media materials. In some implementations of the present invention, the hard particulate material can comprise a power mixture. The method can also involve pressing or otherwise shaping the matrix into a desired form. For example, the method can involve forming the matrix into the shape of an annular crown. The method can then involve placing a plurality of plugs into the matrix. For example, the method can involve placing the bottom surface  602  into a surface of the annular crown that corresponds to a cutting face in order to form a notch  112 ,  212 ,  312 ,  412 . Additionally, or alternatively, the method can involve placing a plug  600  into the body of the annular crown a distance from the surface of the annular crown that corresponds to a cutting face to form an enclosed slot  430 . 
     The method can then infiltrating the matrix with a binder. The binder can comprise copper, zinc, silver, molybdenum, nickel, cobalt, or mixture and alloys thereof. The binder can cool thereby bonding to the matrix (hard particulate material and abrasive cutting media), thereby binding the matrix together. The binder may not significantly bond to the plug  600 , thereby allowing removal of the plug  600  to expose an axially or double tapered waterway. 
     Another, method of the present invention generally includes providing a matrix and filling a mold having plugs  600  placed therein with the matrix. The mold can be formed from a material to which a binder material may not significantly bond to, such as for example, graphite or carbon. The method can then involve densification of the matrix by gravity and/or vibration. The method can then involve infiltrating matrix with a binder comprising one or more of the materials previously mentioned. The binder can cool thereby bonding to the matrix (hard particulate material and abrasive cutting media), thereby binding the matrix together. The binder may not significantly bond to the plug  600  or the mold, thereby allowing removal of the plug  600  to expose an axially or double tapered waterway. 
     Before, after, or in tandem with the infiltration of the matrix, one or more methods of the present invention can include sintering the matrix to a desired density. As sintering involves densification and removal of porosity within a structure, the structure being sintered can shrink during the sintering process. A structure can experience linear shrinkage of between 1% and 40% during sintering. As a result, it may be desirable to consider and account for dimensional shrinkage when designing tooling (molds, dies, etc.) or machining features in structures that are less than fully sintered. 
     According to some implementations of the present invention, the time and/or temperature of the infiltration process can be increased to allow the binder to fill-up a great number and greater amount of the pores of the matrix. This can both reduce the shrinkage during sintering, and increase the strength of the resulting drilling tool. 
     The present invention can thus be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. For example, in some implementations of the present invention, the axially-tapered waterways can be formed by removing material from the crown instead of using plugs. Thus, in some implementations, the axially-tapered waterways can be formed by machining or cutting the waterways into the crown using water jets, lasers, Electrical Discharge Machining (EDM), or other techniques. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.