Abstract: It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

Abstract: It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

Abstract: The present invention provides a more practical hard-coated cutting tool having improved cutting performance during finishing so as to obtain a better finished surface. Provided is a hard-coated cutting tool including a tool body (7) coated with a hard coating (4) and having a cutting edge (3) formed on a ridge line intersecting a flank face (1) and a rake face (2). In the hard-coated cutting tool, the thickness h1 of the hard coating (4) on the flank face (1) side and the thickness h2 of the hard coating (4) on the rake face (2) side near the cutting edge (3) satisfies conditions 8 ?m?h1?30 ?m and 0?h2/h1?0.5 in a cross-section perpendicular to the cutting edge (3) in a range equal to or less than 0.3 times the tool diameter in the axial direction from the tip of the tool.

Abstract: The present invention provides a more practical hard-coated cutting tool having improved cutting performance during finishing so as to obtain a better finished surface. Provided is a hard-coated cutting tool including a tool body (7) coated with a hard coating (4) and having a cutting edge (3) formed on a ridge line intersecting a flank face (1) and a rake face (2). In the hard-coated cutting tool, the thickness h1 of the hard coating (4) on the flank face (1) side and the thickness h2 of the hard coating (4) on the rake face (2) side near the cutting edge (3) satisfies conditions 8 ?m?h1?30 ?m and 0?h2/h1?0.5 in a cross-section perpendicular to the cutting edge (3) in a range equal to or less than 0.3 times the tool diameter in the axial direction from the tip of the tool.

Abstract: A drill including a chisel edge provided at a tip end portion, a spiral first chip discharging groove and a spiral second chip discharging groove, land portions provided between the first chip discharging groove and the second chip discharging groove, and a cut blade provided at an edge of a rake surface of the first chip discharging groove, characterized in that the first chip discharging groove and the second chip discharging groove are provided asymmetrically with respect to a drill rotational center and a land portion behind the first chip discharging groove is larger than a land portion behind the second chip discharging groove.

Abstract: To provide a drill which has a small diameter but deteriorates neither in rigidity like the type having two cut blades and two chip discharging grooves nor in cutting chip discharging property like the type having one cut blade and one cutting chip discharge groove, and which is extremely excellent in practical use while performing the enhancement in hole position precision by a simple improvement, there is provided a drill in which a chisel edge 6 is provided at a tip end portion, a spiral first chip discharging groove 1 and a spiral second chip discharging groove 2 are provided, a land portion 3, 4 is provided between the first chip discharging groove 1 and the second chip discharging groove 2, and a cut blade 5 is provided at an edge of a rake surface 7 of the first chip discharging groove 1, characterized in that the first chip discharging groove 1 and the second chip discharging groove 2 are provided asymmetrically with respect to a drill rotational center O and a land portion 3 behind the first chip dis