Use of the tablets of Diamond or CBN thermally Stable as tips for Rotary drill bits

摘要

The present invention is directed to rotary drill bits and blanks which retain polycrystalline diamond or CBN compacts, but which do not suffer from disadvantages attendant by prior drill designs. The inventive rotary drill bit has a slot within the head thereof which slot has brazed therein with a brazing alloy preferably having a liquidus greater than 700 DEG C, an unsupported thermally-stable polycrystalline diamond or CBN compact. The drill bit is made in another aspect of the invention by forming a slot in the head of the rotary drill and then brazing an unsupported thermally-stable polycrystalline diamond or CBN compact therein with a brazing alloy preferably having a liquidus greater than 700 DEG C. For present purposes, polycrystalline diamond and CBN compacts are termed "thermally stable" by being able to withstand a temperature of 1200 DEG C in a vacuum without any significant structural degradation of the compact occurring.