A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume V.sub.F of the cutting insert and a void volume V.sub.S of the insert fulfill the condition V.sub.S/V.sub.F0.25.

A round double-sided cutting insert includes an insert peripheral surface that includes a plurality of angularly spaced apart indexing latches protruding therefrom and a plurality of cylindrical insert side abutment surfaces that circumferentially alternate with the plurality of indexing latches. An insert holder has a pocket peripheral surface which includes at least one indexing gap and a plurality of pocket side abutment surfaces that circumferentially alternate with the at least one indexing gap. When the cutting insert is releasably attached to the insert holder, to constitute a fastened position of a cutting tool, each of the plurality of pocket side abutment surfaces abuts a respective insert side abutment surface and each indexing gap has a respective indexing latch located therein.

A milling cutter (10), in particular a side milling cutter, is described, having a tool body (12), to which at least one cutting insert (14) is removably secured, said cutting insert being clamped by means of a movable clamping element (16) in the tool body (12) and comprising a cutting edge (18) pointing in the direction of rotation (R). The clamping element (16) clamps the cutting insert (14) from behind and is arranged on the rear side of the cutting insert (14) in the direction of rotation (R) of the milling cutter (10).

A device for mechanically removing material from a workpiece or bulk feedstock, thereby creating chips of removed material while producing a new surface on the workpiece or bulk feedstock. The device comprises a body and at least one round cutting insert that is tangentially mounted on the body. Location and orientation of the insert is characterized by a reference plane offset and an insert axis angle. The insert has an outwardly-facing rake surface on which chips are formed. A planar flank surface is oriented relative to a cutting motion so as to provide clearance between the cutting insert and the surface created by removal of a layer that is converted into chips. A circular cutting edge lies at the intersection of the flank and rake surfaces.

In a circular cutting insert of the present invention, the upper side surface and the lower side surface each include: a plurality of planar restraining faces which are disposed sequentially in a circumferential direction of the upper side surface and the lower side surface so as to interpose a joint portion between each of the planar restraining faces and each have a side disposed on the side surface-intermediate line (N); and a plurality of antivibration restraining faces which are each disposed between two planar restraining faces adjacent through the joint portion and each include an inclined face, and the restraining faces of the lower side surface are disposed so as to be shifted with respect to the restraining faces of the upper side surface by a predetermined angle () around a central axis of a screw insertion hole.

A cutting insert has first and second end surfaces, a peripheral side surface, a reference central axis A perpendicular to and passing through the two surfaces, and a cutting edge having at least one circular-arc-shaped cutting edge. A contact surface portion is formed in the second end surface. The arc-shaped cutting edge is part of virtual circle having a center E which is spaced apart from the central axis A. A longitudinal plane B includes the central axis A and the center E; a median plane C perpendicular to the central axis A passes midway between the two end surfaces; and a virtual plane D perpendicular to both the longitudinal plane B and the median plane C, intersects the circular-arc-shaped cutting edge and traverses the contact surface portion. In a cross-section along the virtual plane D, the contact surface portion is inclined relative to the median plane C.

A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume V.sub.F of the cutting insert and a void volume V.sub.S of the insert fulfill the condition V.sub.S/V.sub.F0.25.

A virtual plane obtained by a locus when a tangent line, which passes through a tool distal end edge, of a virtual circle formed when a tool distal end edge of a cutting edge is rotated in a tool circumferential direction is moved parallel to a tool axial line is a reference plane, an angle (ARt) at which a cross line of the reference plane and the cutting edge virtual plane, is inclined with respect to the tool axial line projected onto the reference plane, is in a range of 30 degrees to 60 degrees, an angle (RR) at which a cutting edge tangent line which passes through the tool distal end edge and extends outward in a tool radial direction, is inclined with respect to a predetermined tool radial direction, which passes through the tool distal end edge, is in a range of 30 degrees to 75 degrees.

Provided are a cutting insert and a tool holder on which the cutting insert is provided. The cutting insert includes a circular upper surface, a circular lower surface, a cylindrical lateral surface for connecting the upper surface and the lower surface, an upper cutting edge formed between the upper surface and the lateral surface, a lower cutting edge formed between the lower surface and the lateral surface, and a plurality of rotation-preventing parts provided at the lateral surface so as to prevent the cutting insert from rotating with respect to the tool holder. Each rotation preventing part includes an inner curved surface recessed toward the center of the lateral surface and convexly rounded so as to form concentric circles in conjunction with the lateral surface, and a stepped rotation-preventing surface parallel to the axial direction of the insert and connecting the inner curved surface and the lateral surface.

A milling tool for an angle grinder has a supporting body, in the shape of a disk and able to be rotationally driven in a direction of rotation, which has an upper side and an underside. The supporting body is formed as a composite body of fiber-reinforced plastic. Cutting element chambers are formed in the supporting body, open to underside, in each of which one cutting element is replaceably arranged.