Abstract: In a face milling cutter, a plurality of cutter inserts are detachably mounted to an outer periphery of a forward end portion of a cutter body. The cutter inserts are arranged in peripherally spaced relation to each other about a rotary axis of the cutter body. Each of the cutter inserts has opposite faces one of which, first face being generally in the form of an octagon having eight ridgelines or a hexagon having six ridgelines, which are formed respectively into cutting edges. Each pair of adjacent cutting edges as a major edge are intersected with each other at an obtuse angle.

Abstract: A combination of a cutter and a fastener unit for fastening the cutter to a tool attachment shaft. The cutter includes a cutter body formed therein with a threaded bore. The fastener unit includes a fastener element having one axial end portion provided on its outer peripheral surface with first threads threadedly engageable with a threaded bore in the tool attachment shaft. The other axial end portion of the fastener element is provided on its outer peripheral surface with second threads threadedly engageable with the threaded bore in the cutter body. The first threads are reverse in a direction of helix to the second treads. An end face of the other axial end portion has a size at most equal to an inner diameter of the threaded bore in the cutter body. If the fastener unit includes a clamper in addition to the fastener element, the cutter body is formed therein with a through bore in place of the threaded bore, and the clamper is received in the through bore.

Abstract: An inserted rotary cutter has a tool body, at least one first insert and at least one wiper insert. The body has a plurality of insert mounting seats formed on a forward end portion thereof. Each insert is releasably mounted to a respective insert mounting seat and has had at least one end cutting edge. The inserts are arranged so that the end cutting edge of the wiper insert projects from the end cutting edge of the first insert forwardly from the body. At least one indicating mark is provided on the body for specifying the insert mounting seat, on which the wiper insert is mounted. The insert mounting seat specified by the mark has a dimensional precision within 0.01 mm in a direction along the axis of rotation.

Abstract: An insert rotary cutter includes a cutter body having a forward end face and at least one first cutter insert releasably attached to the cutter body. The first cutter insert is of a generally triangular shape including a front face having three marginal ridges and three corner ridges. Each marginal ridge is comprised of first, second and third ridge portions. The insert has three main cutting edges each defined by a respective first ridge portion, three auxiliary cutting edges each defined by a respective third ridge portion, three corner cutting edges each defined by a respective corner ridge, and three relief cutting edges each defined by a respective second ridge portion. One of the corner cutting edges and the main and auxiliary cutting edges which intersect the corner cutting edge are indexed in active cutting position. The indexed main cutting edge extends generally axially from the body while the indexed auxiliary cutting edge extends slightly beyond the forward end face.

Abstract: An insert boring tool includes a tool body and a cutting insert releasably mounted thereon. The insert includes a plate defined by front and rear surfaces and a plurality of side faces and having a plurality of corners where adjacent side faces intersect one another. At least one of the corners is removed to provide a corner face. A first cutting edge is defined by the front surface and one of the side faces adjacent to the corner face, and a straight second cutting edge is defined by the front surface and the corner side face. The first and second cutting edges intersect each other at an obtuse angle, and are indexed in an end cutting position. The front surface has a marginal portion extending along the second cutting edge and inclined in such a manner that a thickness of the plate between the marginal portion and the rear surface is progressively reduced toward the second cutting edge.

Abstract: An end mill includes a body having a core receiving recess and a cutting insert releasably mounted thereon. An upper surface of the insert has a first cutting edge ridge serving as an outer peripheral cutting edge, a second cutting edge ridge providing an end cutting edge and a third cutting edge ridge providing an inner peripheral cutting edge. The upper surface has a corner where the second and third cutting edge ridge intersecting each other. The upper surface is composed of a central portion and a corner portion including the corner, whereby the third cutting edge ridge comprising a first edge portion defined by a ridge of the corner portion and a second edge portion defined by a ridge of the central portion. At least that portion of the corner portion disposed adjacent the central portion is inclined providing a thickness of the insert is progressively reduced toward the corner. The insert has a negative radial rake at the outer peripheral cutting edge and a positive axial rake.

Abstract: An end mill comprises an end mill body and a throw-away tip mounted on a forward end of the end mill body so as to be spaced from an axis thereof. A core receiving recess is formed at a center of a forward end face of the end mill body and has a size equal to or greater than a distance between the throw-away tip and the axis of the end mill body. The throw-away tip has an end cutting edge formed by a cutting edge ridge located adjacent the forward end of the end mill body and extending from an outer peripheral side of the end mill body toward an inner peripheral side thereof, and outer and inner peripheral cutting edges respectively formed by cutting edge ridges respectively extending from outer and inner peripheral ends of the end cutting edge toward a rearward end of the end mill body. The end mill body may mount at least two throw-away tips disposed symmetrically with respect to the axis thereof.

Abstract: This invention relates to a vernier drive mechanism, in which a vernier shaft always being subjected to the elasticity of a coil spring is put into a hollow part of a main shaft in a freely rotatable manner, a housing is put outside the main shaft also in the freely rotatable manner, a part having a hexagonal section or a shape causing the similar effect is made at the center of the main shaft, holes open to the hollow part of the main shaft are made on the three planes placed radially at the same angle of the six peripheral planes, balls are put into the holes and are made to contact with a small diameter part of the vernier shaft and the inner surface of the housing by the elasticity of the spring so as to rotate planetarily by the rotation of the vernier shaft and to turn the main shaft at a speed slower than that of the vernier shaft.