Abstract: A boring bar is disclosed having an elongated body adapted to be rotatably driven around a predetermined axis. A longitudinally extending bore is open to at least one end of the body and has an axis which intersects the body axis at an acute angle. A cutting tool has an elongated shank with a cutting edge at one end while the other end of the shank is slidably received within the bore so that the radial displacement of the cutting edge with respect to the cutting axis is directly proportional to the longitudinal position of the shank within the body bore. A nut threadably secured to the body engages a radially extending pin secured to the shank in order to adjust the longitudinal position of the shank within the bore.