Abstract: A chamfer cutter for machining a counter sink in a threaded hole of a work piece is composed of a housing and a tool rest. The housing has a tapering part at a bottom thereof and a chamber at a top thereof. A first channel is defined at an outer periphery of the housing. The tool rest is received in the chamber and has an annular slot defined at an upper portion thereof and a second channel longitudinally defined at an outer periphery. A first screw extends through a first threaded aperture in the housing. A tool blade is received in the first and second channels and fastened by second screws extending through second threaded apertures in the tool rest. A third screw extends through a third threaded aperture in an upper surface of the tool rest and in aligned with the second channel. A fourth screw extends through a fourth threaded aperture longitudinally defined through the tool rest. A blind hole is defined at a bottom surface of the tool rest and a resilient member is provided in the blind hole.