A cutting insert for milling operations, such as, face milling, slot milling, plunge milling, and ramping operations. The cutting insert exhibits a combination of favorable cutting-edge strength, and unique cutting-edge geometry to allow milling operations at relatively high feed rates. The cutting insert includes at least four convex cutting edges. Certain embodiments of square cutting inserts will have four convex cutting edges connected by nose corner regions. Each convex cutting edge includes a first curved cutting-edge region having a radius greater than or equal to two times a radius of the largest circle that may be inscribed on the top surface. Each convex cutting edge also includes a second curved cutting-edge region adjacent the first curved cutting-edge region and having a radius less than or equal to the diameter of the inscribed circle. Each convex cutting edge may also include one or more straight cutting-edge regions.

A cutter holding assembly has a holder, a cutter, and a tightening positioning assembly. The holder has a first positioning recess. The cutter is connected to the holder and has a second positioning recess. The tightening positioning assembly has a positioning block, two tightening elements, and an adjusting element. The positioning block is mounted in the first positioning recess of the holder and the second positioning recess of the cutter. The tightening elements are mounted in two opposite sides of the positioning block. The adjusting element is mounted in the positioning block at a position between the two tightening elements. The adjusting element has a conical abutting surface for pushing the tightening elements to move opposite to each other to abut the opposite side surfaces of one of the first and the second positioning recesses while axially moving. The cutter can be firmly connected to the holder.

A cutter holding assembly has a holder, a cutter, and a tightening positioning assembly. The holder has a first positioning recess. The cutter is connected to the holder and has a second positioning recess. The tightening positioning assembly has a positioning block, two tightening elements, and an adjusting element. The positioning block is mounted in the first positioning recess of the holder and the second positioning recess of the cutter. The tightening elements are mounted in two opposite sides of the positioning block. The adjusting element is mounted in the positioning block at a position between the two tightening elements. The adjusting element has a conical abutting surface for pushing the tightening elements to move opposite to each other to abut the opposite side surfaces of one of the first and the second positioning recesses while axially moving. The cutter can be firmly connected to the holder.

A cutting insert suitable for a small-diameter milling tool is provided. A cutting insert has a rake face, a bottom surface, a circumferential side surface, and a through hole. A first ridgeline at which the rake face and the circumferential side surface intersect each other includes a first main cutting edge, and a first corner cutting edge connected to a tip of the first main cutting edge. The bottom surface includes a first bottom surface that comes closer to the rake face gradually toward a side at which the first main cutting edge is located when viewed from a central axis of the through hole, and a second bottom surface that comes closer to the rake face gradually toward a side opposite to the first main cutting edge when viewed from the central axis. A distance between a virtual intersection line, at which a first virtual surface formed by extending the first bottom surface and a second virtual surface formed by extending the second bottom surface intersect each other, and the first main cutting edge decreases from a tip side, at which the tip of the first main cutting edge is located, toward an end side, at which an end opposite to the tip is located, in an extending direction of the first main cutting edge.

A cutting insert suitable for a small-diameter milling tool is provided. A cutting insert has a rake face, a bottom surface, a circumferential side surface, and a through hole. A first ridgeline at which the rake face and the circumferential side surface intersect each other includes a first main cutting edge, and a first corner cutting edge connected to a tip of the first main cutting edge. The bottom surface includes a first bottom surface that comes closer to the rake face gradually toward a side at which the first main cutting edge is located when viewed from a central axis of the through hole, and a second bottom surface that comes closer to the rake face gradually toward a side opposite to the first main cutting edge when viewed from the central axis. A distance between a virtual intersection line, at which a first virtual surface formed by extending the first bottom surface and a second virtual surface formed by extending the second bottom surface intersect each other, and the first main cutting edge decreases from a tip side, at which the tip of the first main cutting edge is located, toward an end side, at which an end opposite to the tip is located, in an extending direction of the first main cutting edge.

The milling cutter according to the present invention consists of insert holders where these insert holders project from a carrier disc which is adapted for clamping onto the spindle of a machine tool, and the individual holders are connected with one another by braces. Arms are provided between the holders and the carrier disc.

The milling cutter according to the present invention consists of insert holders where these insert holders project from a carrier disc which is adapted for clamping onto the spindle of a machine tool, and the individual holders are connected with one another by braces. Arms are provided between the holders and the carrier disc.

Cutting tool systems including a cutting tool holder and cutting inserts are disclosed. The cutting inserts have eight cutting edges and eight wiper edges. The first and second faces each include at least two cutting edges or two wiper edges on alternating sides of the cutting insert. The cutting edges and wiper edges are structured and arranged to allow the cutting insert to be interchangeably used in both right handed and left handed cutting tool holders.

An indexable and double-sided round cutting insert includes an upper and lower side. A center axis extends between the upper and lower side and a median plane extends perpendicular to the center axis and is situated halfway between the upper and lower side. A side surface has an upper and lower positive clearance surface at an upper positive clearance angle with respect to an upper cutting edge and a lower positive clearance angle with respect to a lower cutting edge. A plurality of protrusions extends along the side surface and protrude in a radial direction perpendicular to the center axis. Each protrusion includes an outer surface, which along the center axis, extends such that a first radial distance from the center axis to the outer surface in the median plane is at least equal to or greater than a second radial distance from the center axis to the outer surface.

An indexable and double-sided round cutting insert includes an upper and lower side. A center axis extends between the upper and lower side and a median plane extends perpendicular to the center axis and is situated halfway between the upper and lower side. A side surface has an upper and lower positive clearance surface at an upper positive clearance angle with respect to an upper cutting edge and a lower positive clearance angle with respect to a lower cutting edge. A plurality of protrusions extends along the side surface and protrude in a radial direction perpendicular to the center axis. Each protrusion includes an outer surface, which along the center axis, extends such that a first radial distance from the center axis to the outer surface in the median plane is at least equal to or greater than a second radial distance from the center axis to the outer surface.