Abstract: A radius endmill has a peripheral cutting edge, a bottom cutting edge, and a rounded corner cutting edges whose ridge line is defined by a circular arc having a given radius as measured in a side view of the endmill that is parallel to the axis. The rounded corner cutting edge is located in a corner portion of the endmill in which the outer peripheral and the axial end intersect each other such that the peripheral cutting edge and the bottom cutting edge are connected to each other through the rounded corner cutting edge. The bottom cutting edge has a radially inner end lying at the axis, and a radially outer end at which the bottom cutting edge is connected to the rounded corner cutting edge. The bottom cutting edge is curved such that its ridge line is defined by a circular arc as seen in a plan view of the endmill that is perpendicular to the axis.

Abstract: A drill in which a flute is formed from a point to a base end side of a body of the drill, on a side face to be rotated about an axis, a cutting edge is formed between a wall surface of the flute which faces a drill rotational direction side and a flank at the point of the body, and a thinned portion is provided to a web portion of the point. The cutting edge is formed in a convex arc shape with a curvature radius 0.25 to 1 times a drill diameter; a radial rake angle at an outer peripheral portion of the cutting edge is ?60 to ?15 degrees; a corner portion, closer to the center of the point, of the thinned portion is formed in an arc shape with a curvature radius of at least 0.1 mm and not greater than 0.05 times the drill diameter; and the drill includes three flutes and three cutting edges.

Abstract: A ball endmill having (a) a cylindrical tool body and (b) ball-nosed end cutting edges each of which includes (b-1) a first portion, (b-2) a second portion and (b-3) a third portion. The first portion is defined by a circular arc which is convex in a direction of rotation of the tool body and which has a first radius of curvature as measured in a distal end view perpendicular to the axis. The second portion is defined by a straight line or a circular arc which is convex in the rotation direction and which has a second radius of curvature as measured in the distal end view. The third portion is defined by a circular arc which is convex in the rotation direction and which has a third radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature. The third radius of curvature is smaller than the second radius of curvature.

Abstract: A neck portion grinding apparatus and method is designed to reduce working man-hours and to improve processing accuracy with respect to a processing of a workpiece. The neck portion grinding apparatus includes a grinding device having a disc-like grinding wheel and a wheel rotating device for rotating the grinding wheel, and a machine tool having a main shaft for rotatably supporting a rotating tool and a table mounting the grinding device thereon, and relatively moving the main shaft and the table by numeral control. A shape of a neck portion of the rotating tool can be changed by relatively moving the main shaft and the table while mutually rotating the rotating tool and the grinding wheel, and grinding the rotating tool by the grinding wheel.

Abstract: A ball endmill having a cylindrical tool body and ball-nosed end cutting edges each of which includes a first portion and a second portion continuous to the first portion. The first and second portions are located at a radially inner portion of each ball-nosed end cutting edge in a distal end view. The first portion is convex in a direction of rotation of the tool body and has a first radius of curvature seen in a distal end view. A ratio of the first radius of curvature to an outside diameter of the cylindrical body is between 0.025 and 0.10. The second portion is convex in the direction of the rotation of the tool body and has a second radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature.

Abstract: A ball endmill having (a) a cylindrical tool body and (b) ball-nosed end cutting edges each of which includes (b-1) a first portion, (b-2) a second portion and (b-3) a third portion. The first portion is defined by a circular arc which is convex in a direction of rotation of the tool body and which has a first radius of curvature as measured in a distal end view perpendicular to the axis. The second portion is defined by a straight line or a circular arc which is convex in the rotation direction and which has a second radius of curvature as measured in the distal end view. The third portion is defined by a circular arc which is convex in the rotation direction and which has a third radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature. The third radius of curvature is smaller than the second radius of curvature.

Abstract: A radius endmill has a peripheral cutting edge, a bottom cutting edge, and a rounded corner cutting edges whose ridge line is defined by a circular arc having a given radius as measured in a side view of the endmill that is parallel to the axis. The rounded corner cutting edge is located in a corner portion of the endmill in which the outer peripheral and the axial end intersect each other such that the peripheral cutting edge and the bottom cutting edge are connected to each other through the rounded corner cutting edge. The bottom cutting edge has a radially inner end lying at the axis, and a radially outer end at which the bottom cutting edge is connected to the rounded corner cutting edge. The bottom cutting edge is curved such that its ridge line is defined by a circular arc as seen in a plan view of the endmill that is perpendicular to the axis.

Abstract: A switch device is provided with an operation key 3 having a first contact portion 315. The operation key 3 is dislocated in a push direction by a push operation. A base member 4 has a second contact portion 41 and a third contact portion 42 electrically conducted by a contact with a first contact portion 315 by the dislocation of the operation key 3 in the push direction. In the base member 4, the second contact portion 41 and the third contact portion 42 are arranged in parallel to each other. A conductive piece 410 projecting toward a third contact portion 42 is connected to the second contact portion 41, and a tip portion of the conductive piece 410 is embedded in the base member 4. A conductive piece 420 projecting toward the second contact portion 41 is connected to the third contact portion 42, and a tip portion of the conductive piece 420 is embedded in the base member 4.

Abstract: A ball endmill having (a) a cylindrical tool body and (b) ball-nosed end cutting edges each of which includes (b-1) a first portion provided by a radially inner portion of each ball-nosed end cutting edge, and (b-2) a second portion provided by a radially outer portion of each ball-nosed end cutting edge. The first portion is defined by a circular arc which is convex in a direction of rotation of the tool body and which has a first radius of curvature as measured in a distal end view perpendicular to the axis. A ratio of the first radius of curvature to an outside diameter of the cylindrical body is not smaller than 0.025 and not larger than 0.10. The second portion is defined by a circular arc which is convex in the direction of the rotation of the tool body and which has a second radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature.

Abstract: A press-fit portion (24) of a press-fit pin (22) is constructed by cutting and outwardly pushing a band-like region (24a), which is placed in the vicinity of the widthwise center of a pin material, in one of orientations of the thickness direction in such a way as to project from peripheral regions (24b) of the band-like region (24a). At that time, the thickness dimension (W3) of the press-fit portion (24) is set to be equal to or less than that W1 of a pin body (23).

Abstract: A press-fit portion (24) of a press-fit pin (22) is constructed by cutting and outwardly pushing a band-like region (24a), which is placed in the vicinity of the widthwise center of a pin material, in one of orientations of the thickness direction in such a way as to project from peripheral regions (24b) of the band-like region (24a). At that time, the thickness dimension (W3) of the press-fit portion (24) is set to be equal to or less than that W1 of a pin body (23).