Abstract: A method and tool for drilling countersunk holes in a composite of materials having different strength and elastic characteristics. The tool includes a front hole cutting section for initially generating the hole, and a rear countersink cutting section providing an enlarged tapered entrance to the hole. The tool has a single flute which extends axially along the length of the front and rear tool cutting sections. The front cutting section includes a planar end surface which is inclined relative to the tool axis and which defines with the flute and a cylindrical outer surface of this section, a single end cutting point and adjacent radial and longitudinal cutting edges. The rear cutting section includes an outer surface which extends radially outward and axially rearward from the front cutting section, and which intersects a leading side of the flute at an acute angle to define a countersink cutting edge.

Abstract: A method and tool for trepanning holes in a composite of materials having different strength and elastic characteristics. The method provides for simultaneous point and surface cutting which occurs at the inner and outer circumferential surfaces of an annular hold being formed. The trepanning tool includes a cylindrical side wall with portions removed at one end to form a plurality of cutting elements or teeth. Each tooth includes a cutting single end point and associated cutting edges, there being inwardly and outwardly directed teeth.

Abstract: A method and tool for drilling holes in a composite of materials having different strength and elastic characteristics. The tool has a planar end surface inclined in two directions relative to the tool axes, and an axially-extending flute which define, with the periphery of the tool, a cutting single end point and adjacent cutting edges which are guided within the hole being formed by three axially-extending wearstrip segments of the tool periphery. The radius of the tool is gradually reduced from the final wearstrip to the side of the flute opposite the cutting single end point. The cutting end portion of the tool may be formed of a very hard carbide material. The method provides for simultaneous point and surface cutting of the composite. Point and surface cutting occur at the outer circumferential surface of the hole generally along a radius of the hole to be drilled. Cutting also occurs along a radius of the hole being generated.