Abstract: An indexable insert drill having a cylindrical body with two flutes and a cutting insert mounted at the end of each flute. The cutting inserts are mounted so that each presents a cutting edge of a length less than the radius of the drill with each edge being positioned to provide negative lead and effectively neutral radial and axial rake. The first of the cutting edges intersects the longitudinal axis of the drill body and extends radially outward to an end area spaced inwardly from the circumference of the drill body. The second of the cutting edges extends from an outer end area radially outward of the drill body circumference to an inner end area radially inward of the radial outermost end of the first cutting edge. Preferably, the first cutting edge extends over two thirds of the radial dimension of the body and has an effective cutting length of at least twice that of the second cutting edge.

Abstract: A single flute drill having a single, replaceable cutting insert which can drill from the solid, as well as being used for other single point machining operatings such as turning, internal and external diameter boring, contouring and facing. The insert is configured and related to the drill body so as to provide a single, radially extending cutting edge which has an effective neutral rake and negative lead. A specific insert structure is also provided for use in the drill. The disclosed insert comprises a solid body having parallel upper and lower faces each generally in the shape of an equilateral parallelogram and joined along their peripheral edges by side walls. One cutting edge is formed along the juncture of one side wall and the upper face and is inclined along its length toward the lower face. A second cutting edge is formed along the juncture of the lower face and a second side wall which intersects the first side wall at a corner.

Abstract: A single flute drill having a single, replaceable cutting insert which can drill from the solid, as well as being used for other single point machining operatings such as turning, internal and external diameter boring, contouring and facing. The insert is configured and related to the drill body so as to provide a single, radially extending cutting edge which has an effective neutral rake and negative lead. A specific insert structure is also provided for use in the drill. The disclosed insert comprises a solid body having parallel upper and lower faces each generally in the shape of an equilateral parallelogram and joined along their peripheral edges by side walls. One cutting edge is formed along the juncture of one side wall and the upper face and is inclined along its length toward the lower face. A second cutting edge is formed along the juncture of the lower face and a second side wall which intersects the first side wall at a corner.