Abstract: A cutting tool such as a drill or reamer for machining a bore in a workpiece is provided with at least one chamfered cutting edge on its distal end having an enlarged radial extent. The chamfered edge is defined between a tapered leading end, and an undercut end, and has a radial extent about 2.5% greater than the radial extent of the shaft of the tool. At least 40% of the length of the chamfered edge is substantially parallel to the axis of rotation of the tool shaft. The tapered and radially enlarged geometry of the chamfered cutting edge advantageously allows the drill or reamer to machine a bore in a workpiece formed from materials having significant spring-back characteristics, such as aluminum, titanium, or nickel alloys without sticking or galling during the machining operation, thereby greatly increasing tool life.