A method of turning very small grooves (13) into a hardened steel work piece (10) using a precision or ultraprecision lathe (70). Positioning of the work piece (10) on the lathe spindle and dressing the work piece to minimize runout, aligning the cutting tool (40) with the face of the work piece to be grooved, the lathe cutting speed and the cutting tool feed rate are all precisely controlled in order to maintain the forces acting on the cutting tool to levels below which fracture of the tool will occur. The cutting tool has a specially configured tip (46) of a cubic boron nitride material . <IMAGE>
