Cutting Tool

Abstract

A cutting tool for use in impinging earth strata includes a cutting tool body having a head portion at an axial forward end, a collar portion axially rearward of the head portion, and a shank portion axially rearward of the collar portion at an axial rearward end, wherein the cutting tool body contains a first socket at the axial forward end thereof. The shank portion generally tapers in the axial rearward direction. The cutting tool also includes a hard cutting member affixed to the cutting tool body within the first socket. The hard cutting member includes an axial forward end and an axial rearward end. The hard cutting member also includes a superhard axial forward portion of the axial forward end thereof, wherein the superhard axial forward portion comprises a substrate and a layer of superhard material adhered to the substrate.

1 . A cutting tool body with a central longitudinal axis, the cutting tool body comprising:
 an axial forward end and an axial rearward end;   a head portion, a shank portion and a collar portion, and the collar portion being mediate of and contiguous with the head portion and the shank portion;   wherein the shank portion has an axial forward end and an axial rearward end and the shank portion has a continuous taper in the axial rearward direction from the axial forward end of the shank portion to the axial rearward end of the shank portion.   
     
     
         2 . The cutting tool body of  claim 1 , wherein a diameter of the shank portion adjacent the axial forward end of the shank portion is larger than a diameter of the shank portion adjacent the axial rearward end. 
     
     
         3 . The cutting tool body of  claim 1 , wherein a diameter of the shank portion decreases linearly from adjacent the axial forward end to the axial rearward end. 
     
     
         4 . A cutting tool for use in impinging earth strata, the cutting tool comprising:
 a cutting tool body having a head portion at an axial forward end, a collar portion axially rearward of the head portion, and a shank portion axially rearward of the collar portion at an axial rearward end, the cutting tool body containing a first socket at the axial forward end thereof;   wherein the shank portion generally tapers in the axial rearward direction; and   a hard cutting member being affixed to the cutting tool body within the first socket, the hard cutting member comprising:
 an axial forward end and an axial rearward end; 
 a superhard axial forward portion at the axial forward end thereof; and 
 a hard axial rearward portion contiguous with and axially rearward of the superhard axial forward portion and having a second socket for receiving the superhard axial forward portion. 
   
     
     
         5 . The cutting tool of  claim 4 , wherein the superhard axial forward portion comprises a substrate and a layer of a superhard material adhered to the substrate. 
     
     
         6 . The cutting tool of  claim 5 , wherein the layer of superhard material includes polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN). 
     
     
         7 . The cutting tool of  claim 5 , wherein the substrate of the superhard axial forward portion generally tapers in the axial rearward direction. 
     
     
         8 . The cutting tool of  claim 7 , wherein the second socket includes sidewalls structured and arranged for receiving the tapered substrate of the superhard axial forward portion. 
     
     
         9 . The cutting tool of  claim 8 , wherein the sidewalls of the second socket generally tapers in the axial rearward direction. 
     
     
         10 . The cutting tool of  claim 8 , wherein the tapered substrate is brazed to the tapered sidewalls of the second socket. 
     
     
         11 . The cutting tool of  claim 4 , wherein the hard axial rearward portion includes a cemented (cobalt) tungsten carbide material. 
     
     
         12 . The cutting tool of  claim 5 , wherein the substrate of the superhard axial forward portion includes a cemented (cobalt) tungsten carbide material. 
     
     
         13 . A cutting tool for use in impinging earth strata, the cutting tool comprising:
 a cutting tool body having a head portion at an axial forward end, a collar portion axially rearward of the head portion, and a shank portion axially rearward of the collar portion at an axial rearward end, the cutting tool body containing a first socket at the axial forward end thereof; and   a hard cutting member being affixed to the cutting tool body within the first socket, the hard cutting member comprising:
 an axial forward end and an axial rearward end; 
 a superhard axial forward portion at the axial forward end thereof, wherein the superhard axial forward portion comprises a substrate and a layer of a superhard material adhered to the substrate, and wherein the substrate of the superhard axial forward portion generally tapers in the axial rearward direction; and 
 a hard axial rearward portion contiguous with and axially rearward of the superhard axial forward portion and having a second socket structured and arranged for receiving the superhard axial forward portion. 
   
     
     
         14 . The cutting tool of  claim 13 , wherein the layer of superhard material includes polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN). 
     
     
         15 . The cutting tool of  claim 13 , wherein the second socket includes sidewalls structured and arranged for receiving the tapered substrate of the superhard axial forward portion. 
     
     
         16 . The cutting tool of  claim 15 , wherein the sidewalls of the second socket generally taper in the axial rearward direction. 
     
     
         17 . The cutting tool of  claim 16 , wherein the tapered substrate is brazed to the tapered sidewalls of the second socket. 
     
     
         18 . The cutting tool of  claim 13 , wherein the shank portion generally tapers in the axial rearward direction. 
     
     
         19 . The cutting tool of  claim 13 , wherein the hard axial rearward portion includes a cemented (cobalt) tungsten carbide material. 
     
     
         20 . The cutting tool of  claim 13 , wherein the substrate of the superhard axial forward portion includes a cemented (cobalt) tungsten carbide material. 
     
     
         21 . The cutting tool body of  claim 1 , wherein the cutting tool body is either rotatable or indexable. 
     
     
         22 . The cutting tool of  claim 4 , wherein the cutting tool body is either rotatable or indexable. 
     
     
         23 . The cutting tool of  claim 13 , wherein the cutting tool body is either rotatable or indexable. 
     
     
         24 . A cutting tool for use in impinging earth strata, the cutting tool comprising:
 a cutting tool body having a head portion at an axial forward end, a collar portion axially rearward of the head portion, and a shank portion axially rearward of the collar portion at an axial rearward end, the cutting tool body containing a first socket at the axial forward end thereof;
 wherein the shank portion generally tapers in the axial rearward direction; and 
   a hard cutting member being affixed to the cutting tool body within the first socket.