Patent Publication Number: US-10767478-B2

Title: Diamond tipped unitary holder/bit

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This invention claims priority to U.S. Provisional Application No. 61/879,353, filed Sep. 18, 2013, claims priority to and is a continuation-in-part of U.S. Non-provisional application Ser. No. 14/487,493, filed Sep. 16, 2014, now U.S. Pat. No. 9,909,416, issued Mar. 6, 2018, and claims priority to and is a continuation-in-part of U.S. Non-provisional application Ser. No. 15/879,078, filed Jan. 24, 2018, to the extent allowed by law and the contents of which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This invention relates to combination bit/holders used in road milling, mining and trenching and, more particularly, to diamond coated tungsten carbide inserts and structure for mounting them as part of a unitary bit/holder combination, tool, and/or pick assembly. 
     BACKGROUND 
     Road milling bits and bit holders, the design of which, when made in differing sizes, can also be used for trenching machines and mining machines, have benefitted greatly from what has been termed a quick change shank, found in the instant inventor&#39;s prior U.S. Pat. Nos. 6,371,567; 6,685,273 and 7,883,155. Additionally, the construction features of the forward end of the advanced bit design found in applicant&#39;s U.S. Pat. No. 6,739,327 has been cited in over 70 later issued patents. The Burkett U.S. Pat. No. 5,161,627 disclosed that one could mount a diamond coated insert in a one-piece bit/bit holder body. A similar structure with a diamond coated tip is found at the Sionett U.S. Pat. No. 4,944,559. These diamond coatings have heretofore been formed in a standard process that includes high temperature, high pressure forming of same on a tungsten carbide high impact substrate. 
     A later version of the present applicant&#39;s prior invention of a quick change shank such as found in the U.S. Pat. No. 6,371,567 is provided in combination with a diamond tip and found at the Hall et al U.S. Pat. No. 8,118,371. 
     With diamond coated tips of road milling machinery, it has been found that the working life of the tip has been greatly increased. As such, it is no longer necessary to provide changeable bits in bit holders. The operating life of bits and bit holders are such that they can be physically combined in a unitary structure. 
     A need has developed for a lower cost combination diamond coated tip and front portion, formerly used on a removable bit, with a quick change bit holder and improvements in tools for inserting and removing same in their working mountings. 
     SUMMARY 
     This disclosure relates generally to unitary bit/bit holder combination, tool, and/or pick assemblies for road milling, mining, and trenching equipment. One implementation of the teachings herein is a tool that includes a body comprising an annular trough and a forward extension axially extending from the annular trough to a forward end of the body; a shank extending axially from a bottom of the body; and an annular tungsten carbide ring comprising a ring bore, the forward extension extending through the ring bore, and the annular tungsten carbide ring adapted to be seated and brazed in the annular trough of the body. 
     These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention may best be understood from the following detailed description of currently preferred embodiments thereof taken in conjunction with the accompanying drawings wherein like numerals refer to like parts, and in which: 
         FIG. 1  is an exploded perspective view of a combination diamond coated bit/bit holder, shown together with a drift pin and cup portion of a tool useful for inserting the bit holder in its bit block (not shown), in accordance with implementations of this disclosure; 
         FIG. 2  is a front elevational view of the combination diamond coated tip bit/bit holder of  FIG. 1  together with two alternate shape diamond coated tip inserts, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 3  is a side elevational view of the combination diamond coated tip/bit holder of  FIG. 2 , showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 4  is a side elevational view of the combination diamond coated bit/bit holder of  FIG. 3 , with a cross section of the female end of the holder insertion tool of  FIG. 1  shown as mounted over the forward end of the bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 5  is a front elevational view of the bit/holder of  FIG. 4  with a cross section of the female end of the bit/holder insertion tool of  FIG. 4  having the drift pin positioned through both the removal tool and the combination bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 6  is an exploded perspective view of a first modification of the combination bit/holder of  FIGS. 1-5  further including an added steel cup into which the tungsten carbide diamond coated tip is inserted which, in turn is inserted in the forward end of the reverse taper tungsten carbide insert, in accordance with implementations of this disclosure; 
         FIG. 6 a    is an elevational view of the tip receiving cup including the bottom pad shown in  FIG. 6  in accordance with implementations of this disclosure; 
         FIG. 6 b    is a top plan view of the cup of  FIG. 6  in accordance with implementations of this disclosure; 
         FIG. 7  is a top ¼ perspective view of a complete bit/holder removal tool for removing the bit/holder from a bit block in accordance with implementations of this disclosure; 
         FIG. 8  is a top ¾ perspective view of the female cup of the bit/holder removal tool showing the Acme threaded top bore therein in accordance with implementations of this disclosure; 
         FIG. 9  is a top ¼ perspective view of a second modification of the bit/holder incorporating an annular steel front end of the bit holder adapted to receive the tungsten carbide diamond coated tip insert therein in accordance with implementations of this disclosure; 
         FIG. 10  is an exploded elevation view of the second modification of the bit/holder of  FIG. 9  with the annular tungsten carbide ring exploded out of its annular pocket more clearly showing the steel front end of the bit holder of  FIG. 9  adapted to receive the tungsten carbide diamond coated insert therein to provide added ductility and shock absorption to the assembly in accordance with implementations of this disclosure; 
         FIG. 11  is a top ¾ perspective of the second modification of the bit/holder of  FIG. 9  as it appears when the bit/holder has been in use a short time with an upper distal annular end worn away in accordance with implementations of this disclosure; 
         FIG. 12  is an exploded elevation view of a third embodiment of a combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 13  is an elevation view of the third embodiment of the combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 14  is an exploded elevation view of a fourth embodiment of a combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 15  is an elevation view of the fourth embodiment of the combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 16  is an exploded elevation view of a fifth embodiment of a combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 17  is an elevation view of the fifth embodiment of the combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; 
         FIG. 18  is an exploded elevation view of a sixth embodiment of a combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure; and 
         FIG. 19  is an elevation view of the sixth embodiment of the combination diamond coated bit/holder, showing invisible internal elements in dotted lines, in accordance with implementations of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a combined diamond coated bit/holder is shown, generally at  15 , in its completed form together with a female cup insertion-removal member  16  and its accompanying drift pin  17 , which extends through the hollow open bottom  18  of the female cup member through aperture  20  and through a body  21  of the combined bit/holder at bore  22  for insertion into a bit block (not shown) which, in turn, is mounted on a rotatable drum (not shown). 
     Referring to  FIGS. 1-3 , a first embodiment of the combination diamond coated bit/holder  15  includes a holder base  21  having an upper body portion  23  and a lower shank portion  24 . The upper and lower shank portion are both made of 4140, 4340, or similar steel. The lower shank portion  24  is a hollow, generally cylindrical member having at least one slot  25  extending axially through the side of the hollow shank from the distal end upwardly toward the top of the shank portion. Alternately, a second, wholly internal slot  26 , may be positioned preferably 180 degrees around the shank from the first slot extending in an axial direction similar to the first slot  25 , however, starting from a position in spatial relation upwardly from the bottom distal end of the shank as shown at  26  in  FIG. 2 . 
     In the preferred embodiment  15 , the shank  24  includes a lower resilient bit block bore engaging portion  27 , and a millable shank portion  28  which may in this embodiment be a few thousandths of an inch. An uppermost part of the shank  30  immediately adjacent the larger body portion  21  includes a generally cylindrical portion having an annular outer surface sized to be press fit into the top of the bit block bore (not shown). As noted previously in U.S. Pat. Nos. 7,883,155, 6,685,273 and 6,371,567, the interference fit between the bottom shank portion  27  and a bit holder bore is substantially larger than a standard interference fit (0.001-0.003) for a solid shank, extending approximately 0.012 to 0.030 inches for a nominal 1½ inch diameter shank for use in road milling. 
     The upper or body portion  21  of the holder  15  includes a radially extending annular flange  31  defining the bottom of what is termed in the industry as a tire portion, diametrically the widest segment of a holder (about 2⅝ inch for a road milling holder). The height of the tire portion may approximate ½ inch and includes a pair of opposing wedge shape cutouts or wedge extraction notches  19 - 19 . From the top of the tire portion, the body generally slopes radially inwardly at  32  and upwardly to perform a ramp-like function with the aim of moving material, macadam, concrete, etc. outwardly from the forward tip of the diamond covered leading portion  33  of the bit/holder. In this preferred embodiment, the mid section of the upper body portion of the holder  23  includes a generally cylindrical segment having at the bottom thereof a cross or through hole  22  substantially perpendicular to the longitudinal axis of the holder. This cross hole  22  extends horizontally through the body portion and forms a receiver for a drift pin  17 , shown most clearly in  FIG. 1  used in connection with the cup portion of a bit/holder insertion tool  16 , a part of which is also shown in  FIG. 1 , and which will be discussed in more detail below. 
     This upper cylindrical segment  23  of the preferred holder body  21  is, with the exception of the through hole  22  mentioned previously, generally solid and provides a substantial portion adding bulk and toughness to the combination bit/holder  15 . As shown most clearly in  FIGS. 2 and 3 , the upper surface  34  of the holder is also made of the same steel as the remainder of the holder and includes an annular trough  35  in which an annular tungsten carbide sleeve  36  is positioned and brazed in place. The trough provides a retainer for an annular braze disk (not shown) which when melted adheres the base of the annular tungsten carbide ring  36  to the trough bottom. Radially inwardly of the tungsten carbide ring is an annular steel axially extending flange  37  that includes a central tapered cutout portion  38 . A reverse taper tungsten carbide insert  40  is fitted into that tapered bore  38  and brazed therein. The top  41  of the tungsten carbide insert  40  extends substantially beyond the top  42  of the steel annular ring  37  and with the exception of a generally cylindrical recess  43  in the top surface thereof is constructed substantially similar to the cutting tool bit shown and disclosed in the present inventor&#39;s issued U.S. Pat. No. 6,739,327. The tungsten carbide reverse taper insert  40  provides a toughened insert for holding a commercially available diamond coated tip  44  which has a generally cylindrical tungsten carbide base  45  and a diamond coated tip which may be conical  33 , flat  46  or oval  47  in cross section as shown in  FIG. 2 . Similarly to the tungsten carbide members previously mentioned, the base  45  of the tip insert  33  is brazed into the tungsten carbide reverse tapered insert member  40 . 
     It should be noted that during assembly, only the top part of the bit body  23  is heated by a inductance coil surrounding same to a temperature just slightly over the melting point of the brazing discs used, i.e., about 1300 degrees F. The careful positioning of the inductance coils provides for heating a minimal area of the upper portion  21  of the bit/holder  15 , thus minimally affecting the grain structure, hardness, toughness etc. of the holder itself. 
     Referring to  FIGS. 4 and 5 , the combination diamond tip bit/holder  15  shown in  FIGS. 4 and 5  is exactly the same as that described in  FIGS. 1-3 . What is shown in  FIGS. 4 and 5  is the mounting of the female or cup shape bit portion  16  of a bit insertion/removal tool, generally at  49 , ( FIG. 7 ) as it appears mounted on the top or holder body  21  of the combination bit/holder  15  together with the drift pin  17  positioned through the central portion  21  of the holder body and the outer annular wall of the cup or female insertion-removal member  16 . 
     As shown in  FIGS. 1, 4 and 5 , the female member  16  is generally cup shaped, having an outer cylindrical wall  50  and an inner, generally cylindrical bore  51  or hollow portion sized to rather loosely fit over the outside of the top  21  of the holder body  15  with a generally flared distal portion  18  sized to fit over the sloped segment  32  of the bottom of the holder body upwardly adjacent the tire portion thereof. 
     A bore  20 - 20  horizontally through the walls of the female cup member  16  is sized and positioned to align with the through or cross bore  22  in the holder body  16  to allow a drift pin  17  to be loosely (slidably) positioned therethrough. The upper hollow or bored out portion of the cup member body fits over the diamond coated bit  33 , tungsten carbide insert  40 , and the tungsten annular ring  36  at the recess  35  in the top wall  34  of the holder body  21 . The upper portion of the cup is, in this embodiment, tapered to a frustoconical shape  53  having a generally flat upper surface  54 . 
     Referring to  FIGS. 7 and 8 , the female or cup portion  16 , as mentioned previously, includes an upper threaded bore  55  centrally therethrough which is adapted to receive an Acme threaded rod  56  therein as a part of a bit insertion/removal tool  50 . In order to maintain the cup  16  on the Acme threaded rod  56 , a nut  57  is threaded on the rod and tightened against the upper annular wall of the cupped member  16  to secure same thereon. The Acme threaded rod  56  extends from the female cup member  16  to a distal stop  58  on the opposite end of the Acme threaded rod. In between is slidably mounted a dual handle hammer member  60  having a central annular portion  61  with a central bore  62  therethrough slightly larger than the outer dimension of the Acme thread for sliding along the threaded rod  56 . 180 degrees apart on opposite sides of the annular central member are mounted hand holds  63 - 64  perpendicularly to the bore through the central member  61 , each having a form fitting grip on its distal end. In operation, once the female cup member  16  is fitted over the top  21  of the bit/holder  15  and the drift pin  17  positioned therethrough, the double hand hold slider  60  may be quickly moved axially along the Acme threaded rod  56  and rammed onto the stop  58  at the distal end thereof to provide axial hammer type outward force to enable the removal of the bit holder  15  from its respective bit block bore (not shown). 
     Referring to  FIGS. 6, 6   a , and  6   b , a first modification of the diamond coated bit/holder  15  of the present invention shown in  FIGS. 1-5  is substantially identical to the holder  21 , tungsten carbide ring  36 , and tip  33  of that embodiment. The only difference being the mounting of a steel receiving cup  65  being about ⅜-1 inch, in height, that is brazed into the forward recess  43  of the reverse taper insert  40 . 
     The diamond coated tip  33 ,  33   a ,  46  and  47  is brazed into the hollow cup forward portion  66  of the steel cup insert  65 . The reasoning behind the addition of the cup shaped thick bottom  67  of the steel insert  65  relates to the ductility of the steel vs. the non-ductility of the tungsten carbide insert  40 . The use of a solid bottomed  67  steel cup  65  member allows the ductility of that thick cylindrical bottom pad to cushion the repeated hammer blows received at the diamond coated tip  33   a . This added ductility to the tip end  33   a  of the bit allows that bit/holder  15  to be used not only in removing MacAdam, but also in removing a concrete and other hardened and non-homogenous materials, thus giving added life and a widened field of use for the bit/holder combination  15  over previously known diamond coated bits. Further, the tungsten carbide to steel to tungsten carbide sequence of the disclosed modification yields substantially stronger bonds than brazing tungsten carbide to tungsten carbide. 
     Referring to  FIGS. 9 and 10 , a second modification  15   a  of the present invention is generally shown. As with the previous modification, the portion of the holder including the shank  24   a , tire portion  31   a , mid and most of the upper body portion  23   a  of the holder  15   a  are identical to that shown in the first embodiment. However, the axially extending upper annular flange  68  of the holder  15   a  immediately inwardly adjacent the tungsten carbide protective ring  36   a  is substantially solid with the exception of a generally cylindrical recess  64  sized for the fitting of the diamond covered commercial insert  33   a  which may be brazed therein. This modification of the uppermost portion of the holder body provides a substantial steel mounting for the diamond coated tungsten carbide body tip  33   a . This substantial steel upper portion  68  provides added ductility, even more so than the steel thick bottomed cup  65  shown in  FIG. 6 . This increased ductility acts as a shock absorber for the diamond coated tungsten carbide tip  33 ,  33   a ,  46  and  47  enabling same to be used in more than just the asphalt or macadam removal, which was a limitation to the use of previously known diamond coated bit tips in road milling. Additionally, the steel to tungsten carbide braze joint between the tip and the holder body is stronger than a tungsten carbide to tungsten carbide braze joint. 
     Referring to  FIG. 11 , the bit/holder  15   a  shown in  FIGS. 9 and 10  is shown as it appears after use in the field has started. In use, the bit/holder  15   a  wears adjacent its tip insert  33   a . The steel annular ring  68  which forms the top of the upper body  23   a  of the bit/holder wears away quickly during use, as shown at  68   a  in  FIG. 11 , somewhat similarly to upper portion  66  of cup  65  shown in  FIGS. 6, 6   a , and  6   b , to the extent where it generally coincides with the top surface of the tungsten carbide annular ring  36   a  after use. 
     The purpose of the extended initial portion of the steel annular ring  68  shown in  FIGS. 9 and 10  is to seat the diamond tipped insert  33   a  in its recess  64  as shown in  FIG. 10 . Initially, the tungsten carbide annular ring  36   a  is seated in its recess  69  at the top of the body portion  23   a  with a ring of brazing material between that recess and the bottom of the annular ring  36   a . A combination of the holder and tungsten carbide annular ring are heated to between 1,650-2,000 degrees F. in the first operation to join those parts of the bit holder together into a unitary structure. The tungsten carbide ring and holder are quenched and tempered to a hardness of RC 40-48, in a separate heat treatment process. 
     Next, the PCD or diamond insert  33   a  is positioned in recess  64  preferably over a silver brazing disc (not shown). This combination is then heated between 1,000-1,300 degrees F. by an induction heater (not shown) which encircles the upper tip portion of the bit holder  15   a . The flow of heat through the annular steel ring  68  more effectively magnetically couples to the iron in the steel in the ring  68  to transfer heat to the tungsten carbide. The heat more efficiently goes through the steel to melt the flux and braze material between the insert  33   a  and the recess  64  of the forward tubular portion of the steel ring body  68 . These two processes that join both the tungsten carbide annular ring  36   a  and the diamond tip insert  33   a  to the upper body  23   a  and recesses  69  and  64 , respectively, of the inner annular ring  68  are made at two differing temperatures to provide a more stable unitary structure in the end-finished bit holder of the present invention. 
     Referring to  FIGS. 12 and 13 , a third embodiment of a combination diamond coated axially shortened bit  100  and bit holder  102  of the present disclosure forms a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104  ( FIG. 13 ). The third embodiment of the bit holder  102  comprises a body  106  and a generally cylindrical hollow shank  108  depending from a bottom of the body  106 . The shank  108  includes an elongate first slot  110  extending from a generally annular distal end  112  of the shank  108  axially upward or forward to an upper termination  114 , which in this embodiment is adjacent the upper or forward end of the shank  108 . In this illustrated embodiment, the shank  108  also includes an internally oriented second slot  116  located approximately 180 degrees around the annular shank  108  from the first slot  110 . The second slot  116  is generally parallel to the first slot  110  and is an internal slot including a rearward semicircular termination  118  inwardly adjacent the distal end  112  of the shank  108  and a forward semicircular termination  120  (not shown) generally coinciding longitudinally and axially with the upper termination  114  of the first slot  110 . 
     In this third embodiment of the bit holder  102 , the shank  108  includes a lower or first tapered portion  122  running axially from a stepped shoulder  124  adjacent the distal end  112  of the shank  108 . The stepped shoulder  124  is disposed between the lower tapered portion  122  and the distal end  112 . A diameter of the stepped shoulder  124  increases, or steps up, in this embodiment, as it axially extends from the distal end  112  to the lower tapered portion  122 . The first tapered portion  122  runs upwardly or axially from the stepped shoulder  124  of the shank  108  and terminates generally mid first slot  110  longitudinally. The shank  108  also includes an annular shoulder  126  separating the lower tapered portion  122  from an upper or second tapered portion  128  which extends from the shoulder  126  to generally adjacent to the top of the shank  108  or forward terminations  114 ,  120  of slots  110 ,  116 , respectively. The annular shoulder  126  is disposed between the lower tapered portion  122  and the upper tapered portion  128 . A diameter of the annular shoulder  126  decreases, or steps down, in this embodiment, as it axially extends from the lower tapered portion  122  to the upper tapered portion  128 . In other embodiments, the lower portion  122  and/or the upper portion  128  of the shank  108  may comprise a generally cylindrical shape, a slight draw angle, or a slight draft angle. In yet other embodiments, the shank  108  can comprise many different configurations. 
     A generally cylindrical top portion  130  of the shank  108  extends from a position adjacent the top or upper terminations  114 ,  120  of slots  110 ,  116 , respectively, towards a generally annular back flange  132  that denotes the base or the bottom of the body  106  of the bit holder  102 . The top of the shank  108  may include a rounded junction  134  between the top portion  130  of the shank  108  and the generally annular flange  132  of the body  106  of the bit holder  102 , which is provided to avoid sharp corners which may provide an area for stress cracks to begin. The generally annular flange  132  includes a pair of horizontal slots or wedge extraction notches  136 - 136  generally perpendicular to the longitudinal axis of the combination bit/holder, one on either side of the generally annular flange  132 . The horizontal slots  136 - 136  are configured to receive a pair of bifurcated fork tines that may be inserted between the base of the body  106  of the bit holder  102  and a base block (not shown) into which the shank  108  of the unitary bit/holder  104  is inserted and retained by outward radial force in use. 
     A central bore  138  longitudinally and axially extending through the shank  108  of the bit holder  102  terminates at bore termination  140 , which in this illustrated embodiment has a conical shape, which is approximately at the upper end of the shank  108 . This allows the generally C-shaped annular sidewall of the shank  108  to radially contract when the shank  108  is mounted in a tapered and/or cylindrical bore in a base block (not shown). 
     In this third illustrated embodiment of the bit holder  102 , the bit holder body  106  includes a generally cylindrical or annular upper body portion  142  depending from a forward end  144  of the upper body portion  142 . A mediate body portion  146  subjacent the upper body portion  142  generally slopes axially and radially outwardly to a radially extending generally cylindrical tire portion  148 . 
     The bit holder body  106 , in order to provide superior brazing of a tungsten carbide ring  150  to the forward end  144  of the upper body portion  142 , includes a forwardly extending annular collar  152  that is created on the bit holder body  106  to provide an annular trough  154  around a forward extension  156  of the bit holder body  106  onto which the annular ring  150  is mounted. In this illustrated embodiment, the annular collar  152  includes a cylindrical bottom inner wall  158  and a tapered top inner wall or countersink  160 . The vertical outer wall of the collar  152  will keep brazing material from flowing outwardly of the joinder between the base of the ring  150  and the annular trough  154  on which the ring  150  is positioned. The annular trough  154  is therearound positioned perpendicular to the axis of the bit holder  102  from the smaller radially oriented annular upper or forward extension  156  ( FIG. 12 ). Around this forward extension  156  is fitted the annular tungsten carbide ring  150 , the forward extension  156  extending through a bore  162  that extends through the annular tungsten carbide ring  150  allowing a bottom of the ring  150  to be seated in the annular trough  154 , which may be brazed into unitary construction with the remainder of the bit holder  102 . In one exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a cylindrical upper section  168  and an outwardly tapered bottom section  170 , as shown in  FIGS. 12 and 13 . An axial length  172  of the ring  150 , corresponding to the generally cylindrical top inner portion  168  of the bore  162  of the ring  150 , is designed to maintain radial support after being brazed. The clearance between the inner diameter of the bore  162  of the annular tungsten carbide ring  150  and the outer diameter of a cylindrical top portion  164  of the forward extension  156  is, in the exemplary implementation, approximately in the range of 0.003 to 0.012 inch per side depending on where the measurement is axially taken. The top or forwardmost portion of the forward extension  156  of the bit holder body  106  terminates generally at a forward end  174  of the bit holder body  106  of the bit holder  102 , located above the forward portion  176  of the annular tungsten carbide ring  150 . In another exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a continuous taper (not shown) from the bottom of the bore  162  to the forward portion of the annular tungsten carbide ring  150 . In other implementations, the forward extension  156  and the bore  162  of the ring  150  can have complementary shaped surfaces. The bit holder  102  may be machined and hardened, or hardened and then machined. The annular tungsten carbide ring  150  may be brazed before or after hardening of the bit holder  102 . 
     In this exemplary implementation of the third embodiment of the bit holder  102 , the forward extension  156  includes a generally cylindrical top portion  164  and an outwardly tapered bottom portion  166 . The generally cylindrical top portion  164 , which forms the unitary steel forward end of the tubular portion of the diamond tool body, includes a bore  178  that axially extends from the forward end  174  to a bore termination  180 , which in this exemplary implementation is flat, adjacent the outwardly tapered bottom portion  166 . The bore  178  provides a space for receiving the complementary shaped bit  100 . The bit tip insert  100  comprises a base  182  and a tip  184  adjacent the base  182  that includes a parabolic curved section below an apex of the bit tip insert  100 . This tip  184  can have a frustoconical shape, a flat generally cylindrical puck shape, a parabolic ballistic shape, a conical shape, and/or an arcuate shape. In this third embodiment, the base  182  includes a generally cylindrical sidewall  186  and a tapered section  190  that extends from the cylindrical sidewall  186  to a generally flat distal end  188  of the bit tip insert  100 . In an alternate embodiment, the base  182  can include a tapered sidewall and the distal end  188  of the bit tip insert  100  can be conical, frustoconical, arcuate, or have a different configuration. In one exemplary implementation of the third embodiment, the bit tip insert  100  can have a diameter in the range of ½ inch to 1⅜ inches. The bit tip insert  100  may be a tungsten carbide insert or may be a tungsten carbide insert that includes an overlay  192  ( FIG. 16 ) of a polycrystalline diamond structure that is applied to an outer surface of the tip  184 . The overlay  192  may be a single coating or outer layer or multiple coatings or outer layers of such industrial diamond material, natural diamond, polycrystalline diamond (PCD) material, and polycrystalline diamond composite or PCD material. 
     To assemble the combination diamond coated axially shortened bit  100  and bit holder  102  of the present disclosure and to form a unitary structure of a bit and bit holder construction of a bit/holder, tool, and/or pick  104 , the annular tungsten carbide ring  150  is positioned around the forward extension  156  and brazed in the annular trough  154  of the bit holder body  106 . The base  182  and the sidewall  186  of the bit tip insert  100  is brazed in the bore  178  of the forward extension  156  at the same time as the carbide ring  150  is brazed, using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint  196  ( FIG. 13 ), which may then be optionally hardened. This braze joint secures the bottom of the tungsten carbide base  182  of the bit tip insert  100  to the bore termination  180  of the bore  178  of the cylindrical top portion  164  of the forward extension  156 , at the forward end  174  of the diamond tool body  106 . In this third embodiment, the annular sidewall  194  of the cylindrical top portion  164  of the forward extension  156  remains in place, as shown in  FIG. 13 , after brazing the bit tip insert  100  in the bore  178 , however, the annular sidewall  194  will be quickly worn away by the abrasive action of the cut material. 
     Referring to  FIGS. 14 and 15 , a fourth embodiment of a combination diamond coated axially shortened bit  100  and bit holder  200  of the present disclosure forms a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104  ( FIG. 15 ). The fourth embodiment of the bit holder  200  comprises a body  106  and a generally cylindrical hollow shank  108  depending from a bottom of the body  106 . The shank  108  includes an elongate first slot  110  extending from a generally annular distal end  112  of the shank  108  axially upward or forward to an upper termination  114 , which in this embodiment is adjacent the upper or forward end of the shank  108 . In this illustrated embodiment, the shank  108  also includes an internally oriented second slot  116  located approximately 180 degrees around the annular shank  108  from the first slot  110 . The second slot  116  is generally parallel to the first slot  110  and is an internal slot including a rearward semicircular termination  118  inwardly adjacent the distal end  112  of the shank  108  and a forward semicircular termination  120  (not shown) generally coinciding longitudinally and axially with the upper termination  114  of the first slot  110 . 
     In this fourth embodiment of the bit holder  200 , the shank  108  includes a lower or first tapered portion  122  running axially from a stepped shoulder  124  adjacent the distal end  112  of the shank  108 . The stepped shoulder  124  is disposed between the lower tapered portion  122  and the distal end  112 . A diameter of the stepped shoulder  124  increases, or steps up, in this embodiment, as it axially extends from the distal end  112  to the lower tapered portion  122 . The first tapered portion  122  runs upwardly or axially from the stepped shoulder  124  of the shank  108  and terminates generally mid first slot  110  longitudinally. The shank  108  also includes an annular shoulder  126  separating the lower tapered portion  122  from an upper or second tapered portion  128  which extends from the shoulder  126  to generally adjacent to the top of the shank  108  or forward terminations  114 ,  120  of slots  110 ,  116 , respectively. The annular shoulder  126  is disposed between the lower tapered portion  122  and the upper tapered portion  128 . A diameter of the annular shoulder  126  decreases, or steps down, in this embodiment, as it axially extends from the lower tapered portion  122  to the upper tapered portion  128 . In other embodiments, the lower portion  122  and/or the upper portion  128  of the shank  108  may comprise a generally cylindrical shape, a slight draw angle, or a slight draft angle. In yet other embodiments, the shank  108  can comprise many different configurations. 
     A generally cylindrical top portion  130  of the shank  108  extends from a position adjacent the top or upper terminations  114 ,  120  of slots  110 ,  116 , respectively, towards a generally annular back flange  132  that denotes the base or the bottom of the body  106  of the bit holder  200 . The top of the shank  108  may include a rounded junction  134  between the top portion  130  of the shank  108  and the generally annular flange  132  of the body  106  of the bit holder  102 , which is provided to avoid sharp corners which may provide an area for stress cracks to begin. The generally annular flange  132  includes a pair of horizontal slots or wedge extraction notches  136 - 136  generally perpendicular to the longitudinal axis of the combination bit/holder, one on either side of the generally annular flange  132 . The horizontal slots  136 - 136  are configured to receive a pair of bifurcated fork tines that may be inserted between the base of the body  106  of the bit holder  200  and a base block (not shown) into which the shank  108  of the unitary bit/holder  104  is inserted and retained by outward radial force in use. 
     A central bore  138  longitudinally and axially extending through the shank  108  of the bit holder  200  terminates at bore termination  140 , which in this illustrated embodiment has a conical shape, which is approximately at the upper end of the shank  108 . This allows the generally C-shaped annular sidewall of the shank  108  to radially contract when the shank  108  is mounted in a tapered and/or cylindrical bore in a base block (not shown). 
     In this fourth illustrated embodiment of the bit holder  200 , the bit holder body  106  includes a generally cylindrical or annular upper body portion  142  depending from a forward end  144  of the upper body portion  142 . A mediate body portion  146  subjacent the upper body portion  142  generally slopes axially and radially outwardly to a radially extending generally cylindrical tire portion  148 . 
     The bit holder body  106 , in order to provide superior brazing of a tungsten carbide ring  150  to the forward end  144  of the upper body portion  142 , includes a forwardly extending annular collar  152  that is created on the bit holder body  106  to provide an annular trough  154  around a forward extension  156  of the bit holder body  106  onto which the annular ring  150  is mounted. In this illustrated embodiment, the annular collar  152  includes a cylindrical bottom inner wall  158  and a tapered top inner wall or countersink  160 . The vertical outer wall of the collar  152  will keep brazing material from flowing outwardly of the joinder between the base of the ring  150  and the annular trough  154  on which the ring  150  is positioned. The annular trough  154  is therearound positioned perpendicular to the axis of the bit holder  200  from the smaller radially oriented annular upper or forward extension  202  ( FIG. 14 ). Around this forward extension  202  is fitted the annular tungsten carbide ring  150 , the forward extension  202  extending through a bore  162  that extends through the annular tungsten carbide ring  150  allowing a bottom of the ring  150  to be seated in the annular trough  154 , which may be brazed into unitary construction with the remainder of the bit holder  200 . In one exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a cylindrical upper section  168  and an outwardly tapered bottom section  170 , as shown in  FIGS. 14 and 15 . An axial length  172  of the ring  150 , corresponding to the generally cylindrical top inner portion  168  of the bore  162  of the ring  150 , is designed to maintain radial support after being brazed. The clearance between the inner diameter of the bore  162  of the annular tungsten carbide ring  150  and the outer diameter of the cylindrical top portion  164  of the forward extension  202  is, in the exemplary implementation, approximately in the range of 0.003 to 0.012 inch per side depending on where the measurement is axially taken. The top or forwardmost portion of the forward extension  202  of the bit holder body  106  terminates generally at a forward end  174  of the bit holder body  106  of the bit holder  200 , located above the forward portion  176  of the annular tungsten carbide ring  150 . In another exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a continuous taper (not shown) from the bottom of the bore  162  to the forward portion of the annular tungsten carbide ring  150 . In other implementations, the forward extension  202  and the bore  162  of the ring  150  can have complementary shaped surfaces. The bit holder  200  may be machined and hardened, or hardened and then machined. The annular tungsten carbide ring  150  may be brazed before or after hardening of the bit holder  200 . 
     In this exemplary implementation of the fourth embodiment of the bit holder  200 , the forward extension  202  includes a generally cylindrical top portion  204  and an outwardly tapered bottom portion  206 . The generally cylindrical top portion  204  forms the unitary steel forward end of the tubular portion of the diamond tool body and provides a forward surface  208  for receiving the complementary shaped bit  100 . The bit tip insert  100  comprises a base  182  and a tip  184  adjacent the base  182  that includes a parabolic curved section below an apex of the bit tip insert  100 . This tip  184  can have a frustoconical shape, a flat generally cylindrical puck shape, a parabolic ballistic shape, a conical shape, and/or an arcuate shape. In this fourth embodiment, the base  182  includes a generally cylindrical sidewall  186  and a tapered section  190  that extends from the cylindrical sidewall  186  to a generally flat distal end  188  of the bit tip insert  100 . In an alternate embodiment, the base  182  can include a tapered sidewall and the distal end  188  of the bit tip insert  100  can be conical, frustoconical, arcuate, or have a different configuration. In one exemplary implementation of the fourth embodiment, the bit tip insert  100  can have a diameter in the range of ½ inch to 1⅜ inches. The bit tip insert  100  may be a tungsten carbide insert or may be a tungsten carbide insert that includes an overlay  192  ( FIG. 16 ) of a polycrystalline diamond structure that is applied to an outer surface of the tip  184 . The overlay  192  may be a single coating or outer layer or multiple coatings or outer layers of such industrial diamond material, natural diamond, polycrystalline diamond (PCD) material, and polycrystalline diamond composite or PCD material. 
     To assemble the combination diamond coated axially shortened bit  100  and bit holder  200  of the present disclosure and to form a unitary structure of a bit and bit holder construction of a bit/holder, tool, and/or pick  104 , the annular tungsten carbide ring  150  is positioned around the forward extension  202  is brazed in the annular trough  154  of the bit holder body  106 . The distal end  188  and the sidewall  186  of the bit tip insert  100  is brazed to the forward surface  208  ( FIG. 14 ) of the forward extension  202  at the same time as the carbide ring  150  is brazed, using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint  209  ( FIG. 15 ), which may then be optionally hardened. This braze joint secures the bottom of the tungsten carbide base  182  and distal end  188  ( FIG. 14 ) of the bit tip insert  100  to the forward surface  208  and cylindrical top portion  204  of the forward extension  202  of the diamond tool body  106 . 
     Referring to  FIGS. 16 and 17 , a fifth embodiment of a combination diamond coated axially shortened bit  100  and bit holder  210  of the present disclosure forms a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104  ( FIG. 17 ). The fifth embodiment of the bit holder  210  comprises a body  106  and a generally cylindrical hollow shank  108  depending from a bottom of the body  106 . The shank  108  includes an elongate first slot  110  extending from a generally annular distal end  112  of the shank  108  axially upward or forward to an upper termination  114 , which in this embodiment is adjacent the upper or forward end of the shank  108 . In this illustrated embodiment, the shank  108  also includes an internally oriented second slot  116  located approximately 180 degrees around the annular shank  108  from the first slot  110 . The second slot  116  is generally parallel to the first slot  110  and is an internal slot including a rearward semicircular termination  118  inwardly adjacent the distal end  112  of the shank  108  and a forward semicircular termination  120  (not shown) generally coinciding longitudinally and axially with the upper termination  114  of the first slot  110 . 
     In this fifth embodiment of the bit holder  210 , the shank  108  includes a lower or first tapered portion  122  running axially from a stepped shoulder  124  adjacent the distal end  112  of the shank  108 . The stepped shoulder  124  is disposed between the lower tapered portion  122  and the distal end  112 . A diameter of the stepped shoulder  124  increases, or steps up, in this embodiment, as it axially extends from the distal end  112  to the lower tapered portion  122 . The first tapered portion  122  runs upwardly or axially from the stepped shoulder  124  of the shank  108  and terminates generally mid first slot  110  longitudinally. The shank  108  also includes an annular shoulder  126  separating the lower tapered portion  122  from an upper or second tapered portion  128  which extends from the shoulder  126  to generally adjacent to the top of the shank  108  or forward terminations  114 ,  120  of slots  110 ,  116 , respectively. The annular shoulder  126  is disposed between the lower tapered portion  122  and the upper tapered portion  128 . A diameter of the annular shoulder  126  decreases, or steps down, in this embodiment, as it axially extends from the lower tapered portion  122  to the upper tapered portion  128 . In other embodiments, the lower portion  122  and/or the upper portion  128  of the shank  108  may comprise a generally cylindrical shape, a slight draw angle, or a slight draft angle. In yet other embodiments, the shank  108  can comprise many different configurations. 
     A generally cylindrical top portion  130  of the shank  108  extends from a position adjacent the top or upper terminations  114 ,  120  of slots  110 ,  116 , respectively, towards a generally annular back flange  132  that denotes the base or the bottom of the body  106  of the bit holder  210 . The top of the shank  108  may include a rounded junction  134  between the top portion  130  of the shank  108  and the generally annular flange  132  of the body  106  of the bit holder  210 , which is provided to avoid sharp corners which may provide an area for stress cracks to begin. The generally annular flange  132  includes a pair of horizontal slots or wedge extraction notches  136 - 136  generally perpendicular to the longitudinal axis of the combination bit/holder, one on either side of the generally annular flange  132 . The horizontal slots  136 - 136  are configured to receive a pair of bifurcated fork tines that may be inserted between the base of the body  106  of the bit holder  210  and a base block (not shown) into which the shank  108  of the unitary bit/holder  104  is inserted and retained by outward radial force in use. 
     A central bore  138  longitudinally and axially extending through the shank  108  of the bit holder  210  terminates at bore termination  140 , which in this illustrated embodiment has a conical shape, which is approximately at the upper end of the shank  108 . This allows the generally C-shaped annular sidewall of the shank  108  to radially contract when the shank  108  is mounted in a tapered and/or cylindrical bore in a base block (not shown). 
     In this fifth illustrated embodiment of the bit holder  210 , the bit holder body  106  includes a generally cylindrical or annular upper body portion  142  depending from a forward end  144  of the upper body portion  142 . A mediate body portion  146  subjacent the upper body portion  142  generally slopes axially and radially outwardly to a radially extending generally cylindrical tire portion  148 . 
     The bit holder body  106 , in order to provide superior brazing of a tungsten carbide ring  150  to the forward end  144  of the upper body portion  142 , includes a forwardly extending annular collar  152  that is created on the bit holder body  106  to provide an annular trough  154  around a forward extension  156  of the bit holder body  106  onto which the annular ring  150  is mounted. In this illustrated embodiment, the annular collar  152  includes a cylindrical bottom inner wall  158  and a tapered top inner wall or countersink  160 . The vertical outer wall of the collar  152  will keep brazing material from flowing outwardly of the joinder between the base of the ring  150  and the annular trough  154  on which the ring  150  is positioned. The annular trough  154  is therearound positioned perpendicular to the axis of the bit holder  210  from the smaller radially oriented annular upper or forward extension  212  ( FIG. 16 ). Around this forward extension  212  is fitted the annular tungsten carbide ring  150 , the forward extension  212  extending through a bore  162  that extends through the annular tungsten carbide ring  150  allowing a bottom of the ring  150  to be seated in the annular trough  154 , which may be brazed into unitary construction with the remainder of the bit holder  210 . In one exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a cylindrical upper section  168  and an outwardly tapered bottom section  170 , as shown in  FIGS. 16 and 17 . An axial length  172  of the ring  150 , corresponding to the generally cylindrical top inner portion  168  of the bore  162  of the ring  150 , is designed to maintain radial support after being brazed. The clearance between the inner diameter of the bore  162  of the annular tungsten carbide ring  150  and the outer diameter of a cylindrical top portion  214  of the forward extension  212  is, in the exemplary implementation, approximately in the range of 0.003 to 0.012 inch per side depending on where the measurement is axially taken. The top or forwardmost portion of the forward extension  212  of the bit holder body  106  terminates generally at a forward end  174  of the bit holder body  106  of the bit holder  210 , located above the forward portion  176  of the annular tungsten carbide ring  150 . In another exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a continuous taper (not shown) from the bottom of the bore  162  to the forward portion of the annular tungsten carbide ring  150 . In other implementations, the forward extension  212  and the bore  162  of the ring  150  can have complementary shaped surfaces. The bit holder  210  may be machined and hardened, or hardened and then machined. The annular tungsten carbide ring  150  may be brazed before or after hardening of the bit holder  210 . 
     In this exemplary implementation of the fifth embodiment of the bit holder  210 , the forward extension  212  includes the generally cylindrical top portion  214  and an outwardly tapered bottom portion  216 . The forward extension  212 , which forms the unitary steel forward end of the tubular portion of the diamond tool body, includes a bore  218  that axially extends from the forward end  174 , through the generally cylindrical top portion  214  and partially through the tapered bottom portion  216 , to a bore termination  220 , which in this exemplary implementation is flat, adjacent the forward end  144  of the upper body portion  142 . The bore  218  provides a space for receiving a generally cylindrical tungsten carbide extension plug  222  and the complementary shaped bit  100 . The bit tip insert  100  comprises a base  182  and a tip  184  adjacent the base  182  that includes a parabolic curved section below an apex of the bit tip insert  100 . This tip  184  can have a frustoconical shape, a flat generally cylindrical puck shape, a parabolic ballistic shape, a conical shape, and/or an arcuate shape. In this fifth embodiment, the base  182  includes a generally cylindrical sidewall  186  and a tapered section  190  that extends from the cylindrical sidewall  186  to a generally flat distal end  188  of the bit tip insert  100 . In an alternate embodiment, the base  182  can include a tapered sidewall and the distal end  188  of the bit tip insert  100  can be conical, frustoconical, arcuate, or have a different configuration. In one exemplary implementation of the fifth embodiment, the bit tip insert  100  can have a diameter in the range of ½ inch to 1⅜ inches. The bit tip insert  100  may be a tungsten carbide insert or may be a tungsten carbide insert that includes an overlay  192  ( FIG. 16 ) of a polycrystalline diamond structure that is applied to an outer surface of the tip  184 . The overlay  192  may be a single coating or outer layer or multiple coatings or outer layers of such industrial diamond material, natural diamond, polycrystalline diamond (PCD) material, and polycrystalline diamond composite or PCD material. 
     To assemble the combination diamond coated axially shortened bit  100  and bit holder  210  of the present disclosure to form a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104  ( FIG. 17 ). The annular tungsten carbide ring  150  is positioned around the forward extension  212  and brazed in the annular trough  154  of the bit holder body  106 . The base  182  and the sidewall  186  of the bit tip insert  100  is brazed to a forward end  224  of the tungsten carbide extension plug  222  at the same time as the carbide ring  150  is brazed, using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint  228  ( FIG. 17 ) between the base  182  of the bit tip insert  100  and the forward end  224  of the tungsten carbide extension plug  222 , which may then be optionally hardened. A distal end  226  of the tungsten carbide extension plug  222  is brazed in the bore  218  of the forward extension  212  at the same time as the bit tip insert  100  and the carbide ring  150  are brazed, using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint, which may then be optionally hardened. This braze joint secures the distal end  226  of the tungsten carbide extension plug  222  to the bore termination  220  and to the bore  218  of the forward extension  212 , adjacent the forward end  174  of the diamond tool body  106 . The three parts, the bit tip insert  100 , the tungsten carbide ring  150 , and the tungsten carbide extension plug  222 , are brazed together in a one step brazing process. In this fifth embodiment, the annular sidewall  194  of the cylindrical top portion  214  of the forward extension  212  remains in place, as shown in  FIG. 17 , after brazing the combination bit tip insert  100  and tungsten carbide extension plug  222  in the bore  218 , however, the annular sidewall  194  will be quickly worn away by the abrasive action of the cut material. 
     Referring to  FIGS. 18 and 19 , a sixth embodiment of a combination diamond coated axially shortened bit  100  and bit holder  230  of the present disclosure forms a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104  ( FIG. 19 ). The sixth embodiment of the bit holder  230  comprises a body  106  and a generally cylindrical hollow shank  108  depending from a bottom of the body  106 . The shank  108  includes an elongate first slot  110  extending from a generally annular distal end  112  of the shank  108  axially upward or forward to an upper termination  114 , which in this embodiment is adjacent the upper or forward end of the shank  108 . In this illustrated embodiment, the shank  108  also includes an internally oriented second slot  116  located approximately 180 degrees around the annular shank  108  from the first slot  110 . The second slot  116  is generally parallel to the first slot  110  and is an internal slot including a rearward semicircular termination  118  inwardly adjacent the distal end  112  of the shank  108  and a forward semicircular termination  120  (not shown) generally coinciding longitudinally and axially with the upper termination  114  of the first slot  110 . 
     In this sixth embodiment of the bit holder  230 , the shank  108  includes a lower or first tapered portion  122  running axially from a stepped shoulder  124  adjacent the distal end  112  of the shank  108 . The stepped shoulder  124  is disposed between the lower tapered portion  122  and the distal end  112 . A diameter of the stepped shoulder  124  increases, or steps up, in this embodiment, as it axially extends from the distal end  112  to the lower tapered portion  122 . The first tapered portion  122  runs upwardly or axially from the stepped shoulder  124  of the shank  108  and terminates generally mid first slot  110  longitudinally. The shank  108  also includes an annular shoulder  126  separating the lower tapered portion  122  from an upper or second tapered portion  128  which extends from the shoulder  126  to generally adjacent to the top of the shank  108  or forward terminations  114 ,  120  of slots  110 ,  116 , respectively. The annular shoulder  126  is disposed between the lower tapered portion  122  and the upper tapered portion  128 . A diameter of the annular shoulder  126  decreases, or steps down, in this embodiment, as it axially extends from the lower tapered portion  122  to the upper tapered portion  128 . In other embodiments, the lower portion  122  and/or the upper portion  128  of the shank  108  may comprise a generally cylindrical shape, a slight draw angle, or a slight draft angle. In yet other embodiments, the shank  108  can comprise many different configurations. 
     A generally cylindrical top portion  130  of the shank  108  extends from a position adjacent the top or upper terminations  114 ,  120  of slots  110 ,  116 , respectively, towards a generally annular back flange  132  that denotes the base or the bottom of the body  106  of the bit holder  230 . The top of the shank  108  may include a rounded junction  134  between the top portion  130  of the shank  108  and the generally annular flange  132  of the body  106  of the bit holder  230 , which is provided to avoid sharp corners which may provide an area for stress cracks to begin. The generally annular flange  132  includes a pair of horizontal slots or wedge extraction notches  136 - 136  generally perpendicular to the longitudinal axis of the combination bit/holder, one on either side of the generally annular flange  132 . The horizontal slots  136 - 136  are configured to receive a pair of bifurcated fork tines that may be inserted between the base of the body  106  of the bit holder  230  and a base block (not shown) into which the shank  108  of the unitary bit/holder  104  is inserted and retained by outward radial force in use. 
     A central bore  138  longitudinally and axially extending through the shank  108  of the bit holder  230  terminates at bore termination  140 , which in this illustrated embodiment has a conical shape, which is approximately at the upper end of the shank  108 . This allows the generally C-shaped annular sidewall of the shank  108  to radially contract when the shank  108  is mounted in a tapered and/or cylindrical bore in a base block (not shown). 
     In this sixth illustrated embodiment of the bit holder  230 , the bit holder body  106  includes a generally cylindrical or annular upper body portion  142  depending from a forward end  144  of the upper body portion  142 . A mediate body portion  146  subjacent the upper body portion  142  generally slopes axially and radially outwardly to a radially extending generally cylindrical tire portion  148 . 
     The bit holder body  106 , in order to provide superior brazing of a tungsten carbide ring  150  to the forward end  144  of the upper body portion  142 , includes a forwardly extending annular collar  152  that is created on the bit holder body  106  to provide an annular trough  154  around a forward extension  232  of the bit holder body  106  onto which the annular ring  150  is mounted. In this illustrated embodiment, the annular collar  152  includes a cylindrical bottom inner wall  158  and a tapered top inner wall or countersink  160 . The vertical outer wall of the collar  152  will keep brazing material from flowing outwardly of the joinder between the base of the ring  150  and the annular trough  154  on which the ring  150  is positioned. The annular trough  154  is therearound positioned perpendicular to the axis of the bit holder  230  from the smaller radially oriented annular upper or forward extension  232  ( FIG. 18 ). Around this forward extension  232  is fitted the annular tungsten carbide ring  150 , the forward extension  232  extending through a bore  162  that extends through the annular tungsten carbide ring  150  allowing a bottom of the ring  150  to be seated in the annular trough  154 , which is be brazed into unitary construction with the remainder of the bit holder  230  in a one step process. In one exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a cylindrical upper section  168  and an outwardly tapered bottom section  170 , as shown in  FIGS. 18 and 19 . An axial length  172  of the ring  150 , corresponding to the generally cylindrical top inner portion  168  of the bore  162  of the ring  150 , is designed to maintain radial support after being brazed. The clearance between the inner diameter of the bore  162  of the annular tungsten carbide ring  150  and the outer diameter of a cylindrical top portion  234  of the forward extension  232  is, in the exemplary implementation, approximately in the range of 0.003 to 0.012 inch per side depending on where the measurement is axially taken. The top or forwardmost portion of the forward extension  232  of the bit holder body  106  terminates generally at a forward end  174  of the bit holder body  106  of the bit holder  230 , located above the forward portion  176  of the annular tungsten carbide ring  150 . In another exemplary implementation, the bore  162  of the annular tungsten carbide ring  150  may comprise a continuous taper (not shown) from the bottom of the bore  162  to the forward portion of the annular tungsten carbide ring  150 . In other implementations, the forward extension  232  and the bore  162  of the ring  150  can have complementary shaped surfaces. The bit holder  230  may be machined and hardened, or hardened and then machined. The annular tungsten carbide ring  150  may be brazed before or after hardening of the bit holder  230 . 
     In this exemplary implementation of the sixth embodiment of the bit holder  230 , the forward extension  232  includes the generally cylindrical top portion  234  and an outwardly tapered bottom portion  236 . The forward extension  232 , which forms the unitary steel forward end of the tubular portion of the diamond tool body, includes a bore  238  that axially extends from the forward end  174 , through the generally cylindrical top portion  234  and partially through the tapered bottom portion  236 , to a bore termination  240 . In this illustrated exemplary embodiment, the bore  238  includes a generally cylindrical bore section  242  that axially extends from the forward end  174  through the generally cylindrical top portion  234  to a location adjacent the tapered bottom portion  236 , a tapered bore section  244  that axially extends from a distal end  246  of the generally cylindrical bore section  242  to the bore termination  240 , which in this exemplary implementation is conical, adjacent the forward end  144  of the upper body portion  142 . The bore  238  provides a space for receiving a tapered tungsten carbide extension plug  248  and the complementary shaped bit  100 . The bit tip insert  100  comprises a base  182  and a tip  184  adjacent the base  182  that includes a parabolic curved section below an apex of the bit tip insert  100 . This tip  184  can have a frustoconical shape, a flat generally cylindrical puck shape, a parabolic ballistic shape, a conical shape, and/or an arcuate shape. In this sixth embodiment, the base  182  includes a generally cylindrical sidewall  186  and a tapered section  190  that extends from the cylindrical sidewall  186  to a generally flat distal end  188  of the bit tip insert  100 . In an alternate embodiment, the base  182  can include a tapered sidewall and the distal end  188  of the bit tip insert  100  can be conical, frustoconical, arcuate, or have a different configuration. In one exemplary implementation of the sixth embodiment, the bit tip insert  100  can have a diameter in the range of ½ inch to 1⅜ inches. The bit tip insert  100  may be a tungsten carbide insert or may be a tungsten carbide insert that includes an overlay  192  ( FIG. 16 ) of a polycrystalline diamond structure that is applied to an outer surface of the tip  184 . The overlay  192  may be a single coating or outer layer or multiple coatings or outer layers of such industrial diamond material, natural diamond, polycrystalline diamond (PCD) material, and polycrystalline diamond composite or PCD material. 
     To assemble the combination diamond coated axially shortened bit  100  and bit holder  230  of the present disclosure to form a unitary structure bit and bit holder construction of a bit/holder, tool, and/or pick  104 , the annular tungsten carbide ring  150  is positioned around the forward extension  232  and brazed in the annular trough  154  of the bit holder body  106 . The base  182  and the sidewall  186  of the bit tip insert  100  is brazed to a forward end  250  of the tungsten carbide extension plug  248  at the same time as the carbide ring  150 , using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint  254  ( FIG. 19 ) between the base  182  of the bit tip insert  100  and the forward end  250  of the tungsten carbide extension plug  248 , which may then be optionally hardened. A distal end  252 , which in this illustrated embodiment is conical, of the tungsten carbide extension plug  248  is brazed in the bore  238  of the forward extension  232  at the same time as the bit tip insert  100  and the carbide ring  150  are brazed, using, for example, a disc shaped or ring shaped braze material, and also creating a high strength braze joint, which may then be optionally hardened. This braze joint secures the distal end  252  of the tungsten carbide extension plug  248  to the bore termination  240  and to the bore  238  of the forward extension  232 , adjacent the forward end  174  of the diamond tool body  106 . The three parts, the bit tip insert  100 , the tungsten carbide ring  150 , and the tungsten carbide extension plug  248 , are brazed together in a one step brazing process. In this sixth embodiment, the annular sidewall  194  of the cylindrical top portion  234  of the forward extension  232  remains in place, as shown in  FIG. 19 , after brazing the combination bit tip insert  100  and tungsten carbide extension plug  248  in the bore  238 , however, the annular sidewall  194  will be quickly worn away by the abrasive action of the cut material. This sidewall  194  can also be machined away after brazing. 
     As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, “X includes at least one of A and B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes at least one of A and B” is satisfied under any of the foregoing instances. The articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Moreover, use of the term “an implementation” or “one implementation” throughout is not intended to mean the same embodiment, aspect or implementation unless described as such. 
     While the present disclosure has been described in connection with certain embodiments and measurements, it is to be understood that the present disclosure is not to be limited to the disclosed embodiments and measurements but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.