Cutting element having a self sharpening tip

Abstract

A cutting element including a shank portion and a conical cutting portion. The conical cutting portion has a narrow end and a broad end connected to the shank portion. The conical cutting portion narrow end has an insert receiving recess, and an insert is secured in the insert receiving recess. The insert has an outer layer made of tungsten carbide, and an inner core made of a material with a greater hardness than the outer layer.

1 . A cutting element including
 a shank portion, a conical cutting portion, the conical cutting portion having a narrow end and a broad end connected to the shank portion, said conical cutting portion narrow end having an insert receiving recess, and an insert secured in said insert receiving recess, said insert having an outer layer made of tungsten carbide, and an inner core made of a material with a greater hardness than the outer layer.   
   
   
       2 . A cutting element in accordance with  claim 1  wherein said inner core is made of diamond. 
   
   
       3 . A cutting element in accordance with  claim 1  wherein said insert forms a point at the end of the conical cutting portion, and said inner core is exposed at said point. 
   
   
       4 . A cutting element in accordance with  claim 1  wherein said broad end is wider than said shank portion, forming a shoulder between the conical cutting portion and the shank portion. 
   
   
       5 . A cutting element in accordance with  claim 1  wherein said conical portion has a cylindrical axis, and said insert is on the cylindrical axis of said conical portion.