Abstract: A high speed rotary boring tool has a plurality of cutter inserts evenly spaced around the circumference of a boring bar. Each cutter insert is individually adjustable so that its cutting tip is spaced a desired distance from the tool rotational axis. Each cutter insert is mounted so that its leading face has a zero rake angle in the axial direction, and a negative rake angle in the radial direction. The cutting tip on each insert is defined by two chamfer surfaces on the intersecting edges of the insert leading face, such that each chamfer surface acts as a chip-deflector surface. The boring tool is designed for cutting action during axial feed into the hole and also during axial feed out of the hole.