Patent ID: 7520701

Claim:
A CBN cutting tool for high-quality, high-efficiency cutting comprising cutting portions formed by cBN-based sintered bodies, characterized in that each of said cBN-based sintered bodies has an end flank, a side flank, an arcuate nose, a rake face and a negative land formed between said rake face and said arcuate nose, said negative land and said rake face defining a ridgeline therebetween which extends from point Q 1 at which said end flank, rake face and negative land intersect each other to point Q 2 at which said side flank, rake face and negative land intersect each other, said end flank and said negative land defining a first cutting edge therebetween, said side flank and said negative land defining a second cutting edge therebetween, said first and second cutting edges extending from an apex P of said arcuate nose to points Q 1 and Q 2 , respectively, said first and second cutting edges being the lowest relative to said rake face at said apex P and rising toward points Q 1 and Q 2 , respectively, and wherein a straight line connecting said apex P and point Q 1 forms an inclination angle β′ of not less than 20 degrees and not more than 35 degrees with respect to said rake face.