In a cutting tool having an indexable lay-down cutting insert with a central body portion and three circumferentially spaced apart cutting portions, the cutting insert is removably secured to an elongated holding portion of an insert holder. Each cutting portion has a cutting edge with first and second cutting end points, the cutting edge formed at the intersection of an upward facing rake surface and a radially outward facing relief surface. In a top view of the cutting insert, parallel imaginary first and second vertical planes containing the first and second cutting end points, intersect the central body portion at first and second body side points, which are located first and second cutting distances from the first and second cutting end points, respectively. Each of the first and second cutting distances is greater than twenty-five percent of the first radius of an imaginary first circle circumscribing the cutting insert.

Technology for turning selected portions of a workpiece by a cutting tool is described. The described technology can provide methods and apparatuses for turning areas of a part so that corner strikes are avoided upon material entry, burr formation upon material exit is eliminated or significantly reduced, and/or the instantaneous cut depth continuously changes to avoid notch formation. The resulting superior machining conditions can enable more aggressive machining parameters to be used in the tool path, thereby resulting in reduced machining time and load.

In a cutting tool having an indexable lay-down cutting insert with a central body portion and three circumferentially spaced apart cutting portions, the cutting insert is removably secured to an elongated holding portion of an insert holder. Each cutting portion has a cutting edge with first and second cutting end points, the cutting edge formed at the intersection of an upward facing rake surface and a radially outward facing relief surface. In a top view of the cutting insert, parallel imaginary first and second vertical planes containing the first and second cutting end points, intersect the central body portion at first and second body side points, which are located first and second cutting distances from the first and second cutting end points, respectively. Each of the first and second cutting distances is greater than twenty-five percent of the first radius of an imaginary first circle circumscribing the cutting insert.

A turning insert includes a top surface, an opposite bottom surface, a reference plane located parallel to and between the top surface and the bottom surface, and a center axis extending perpendicular to the reference plane and intersecting the reference plane (RP), the top surface and the bottom surface. Side surfaces connect the top surface and the bottom surface. Three nose portions are formed symmetrically relative to the center axis. Each nose portion includes a first cutting edge, a second cutting edge and a convex nose cutting edge connecting the first) and second cutting edges. In a top view the first and second cutting edges on the same nose portion form a nose angle of 25-50° relative to each other. The distance from the first cutting edge to the reference plane varies in such a way that that this distance is decreasing at increasing distance from the nose cutting edge.

A structure for cooling a rake face of a cutting insert in a region near a tip of a cutting edge. The cutting insert includes a rake face, a cutting edge formed on an outer periphery of the rake face, a base portion that supports the rake face, and an internal cooling path through which fluid for cooling the rake face flows. The internal cooling path includes an introduction flow path and a cooling flow path, and the cooling flow path is disposed behind a region in which a chip of a workpiece comes into contact with rake face. The cooling flow path is provided at a depth of less than or equal to 1.5 mm from the rake face.

An insert based on an aspect includes a first face, a second face located opposite to the first face, a third face located between the first face and the second face, and a cutting edge located on an intersection of the first face and the third face. The first face includes a first region inclined so as be close to the second face as being separated away from the cutting edge. A virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face. A ten-point average of roughness the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b, and Rz1a is larger than Rz1b.

An insert based on an aspect includes a first face, a second face located opposite to the first face, a third face located between the first face and the second face, and a cutting edge located on an intersection of the first face and the third face. The first face includes a first region inclined so as be close to the second face as being separated away from the cutting edge. A virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face. A ten-point average of roughness the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b, and Rz1a is larger than Rz1b.

A cutting tool has a holder and an indexable cutting insert secured therein. The holder has a head and a shank extending therefrom along a holder axis, the head having spaced apart lower and upper clamping portions located on opposite sides of a first plane containing the holder axis. The lower clamping portion has spaced apart first and second lower clamping surfaces located on opposite sides of a second plane perpendicular to the first plane, and the upper clamping portion has an upper clamping surface intersected by the second plane. The cutting insert has a peripheral surface with a plurality of circumferentially spaced cutting portions, and the second plane intersects the plurality of cutting portions. The upper clamping surface makes contact with a first abutment portion of the peripheral surface, and a second abutment portion of the peripheral surface makes contact with the first and second lower clamping surfaces.

A tool holder (12) for an indexable cutting insert (13) is disclosed, comprising a tool holder base body (15), having a receiving pocket (20) for receiving an indexable cutting insert (13) and a fastening pin (17). The fastening pin (17) can assume a mounting position and a clamping position. In the mounting position, the fastening pin (17) can be positioned in a fastening opening (14) of an indexable cutting insert (13). In the clamping position, an indexable cutting insert (13) can be fixed in the receiving pocket (20) by means of the fastening pin (17). The fastening pin (17) is arranged on a fastening slide (16), displaceably arranged in the tool holder base body (15). Furthermore, a cutting tool (10) is disclosed, having a tool holder (12) and an indexable cutting insert (13).

A blade-shaped cutting insert has opposing first and second insert side surfaces with a peripheral surface extending therebetween, and a first cutting portion having a first primary cutting edge extending between the first and second insert side surfaces, defining a maximum insert width of the cutting insert. The peripheral surface includes an upper surface and first and second diverging flank surfaces bisected by a first plane transverse to the upper surface. The cutting insert has a maximum insert length measured perpendicular to the first plane which is more than sixteen times greater than the maximum insert width, and a maximum insert height measured parallel to the first plane which is more than ten times greater than the maximum insert width. The cutting insert is removably secured in an insert receiving pocket of a tool holder, which is defined by an upper clamping jaw and a lower clamping jaw.