Patent ID: 7313991

Claim:
A cutting insert comprising: a base body comprising cemented carbide; at least one cutting body comprising ceramic material; said at least one cutting body comprising a cutting edge to cut into metal; and said at least one cutting body being joined to said base body: said base body comprises at least one recess; said at least one recess being configured to receive said at least one cutting body; said at least one recess is substantially, congruently shaped with respect to at least a portion of said at least one ceramic cutting body; said at least one ceramic cutting body is in the shape of a circular truncated cone; said at least one ceramic cutting body has a first end surface and a second surface disposed at opposite ends of said truncated cone; said first end surface is smaller in diameter than said second end surface; said at least one recess comprises a bottom surface and a side surface disposed substantially transverse to said bottom surface; said first end surface is attached to said bottom surface of said at least one recess; said second end surface comprises a cutting edge formed at the exposed circular perimeter edge of said second end surface of the circular truncated cone and extends in the shape of a partial circle; said cutting edge comprises a partial circle of at least 200° and not more than 230°; said cutting insert defines a clearance angle of one of (A) and (B): (A) <10°; and (B) 7 ±2°; said at least one cutting body is bonded or brazed into said at least one recess; said base body comprises at least one groove extending transversely to the longitudinal axis of said cutting insert for fastening said cutting insert to a toolholder; said at least one groove is defined on either side by raised portions extending substantially parallel to said at least one groove; said cutting insert is configured as an indexable insert; said indexable cutting insert is fitted with two, three, or four cutting bodies; and the maximum diameter of said at least one cutting body is in the range of 4±0.05 mm to 10±0.05 mm.