A polygonal cutting blade having a circular arc-shaped groove in a hole includes a blade body composed of an upper surface, a lower surface and a plurality of main side surfaces connecting the upper surface and the lower surface. The blade body has a central hole penetrating through the upper surface and the lower surface, and is centrally symmetrical about a central axis of the central hole. At least one set of positioning side surface comprised of adjacent two of the main side surfaces is provided. An inner surface of the central hole has at least one circular arc-shaped groove fitting with a fastening screw for fixing the cutting blade. The circular arc-shaped groove directly faces toward an intersection of the two main side surfaces of the set of positioning side surface. A groove central axis of the circular arc-shaped groove has an offset distance from the central axis.

Provided is a cutting insert configured to be able to realize downsizing of a cutting tool. A cutting insert includes: an upper surface and a lower surface facing each other and having a plurality of corner parts; a side surface connecting the upper surface and the lower surface and forming intersecting edges with the upper surface and the lower surface, respectively; and a through hole that has a central axis extending from the upper surface to the lower surface and that is formed for penetration from the upper surface to the lower surface. A corner cutting edge arranged at a position corresponding to a corner part of the upper surface, a minor cutting edge connected to a first end of the corner cutting edge, and a major cutting edge connected to a second end of the corner cutting edge are formed on the intersecting edge between the upper surface and the side surface. A flank of the corner cutting edge and a recessed part located on the lower surface side of the flank of the corner cutting edge are formed on the side surface.

A cutting tool includes a toolholder and a cutting insert. The toolholder includes a toolholder pocket having a pocket wall including a first anti-rotation engagement surface and a second anti-rotation engagement surface. The cutting insert is mounted in the toolholder pocket. The cutting insert includes: an upper surface, the upper surface having a plurality circular sinusoidal cutting edges; a lower surface opposite the upper surface; and an exterior sidewall between the upper surface and the lower surface. The first anti-rotation engagement surface and the second anti-rotation engagement surface of the pocket wall of the toolholder engage the exterior sidewall of the cutting insert to resist rotation of cutting insert.

The present disclosure relates to a cutting insert, and a cutting insert according to the present disclosure comprises: an upper surface and a lower surface oriented in opposite directions; a first and a second shorter side surface connecting the upper surface and the lower surface to each other and oriented in opposite directions; a first and a second longer side surfaces connecting the upper surface and the lower surface to each other, connecting the first and the second shorter side surfaces to each other, oriented in opposite directions, and being longer than the first and the second shorter side surfaces; and a through hole extending through the upper surface and the lower surface, wherein when viewed toward the upper surface, the first longer side surface has two side portions, each side portion having an inclined shape with reference to the center portion.

An indexable cutting tool stably clamps cutting inserts and prevents contact between head parts of fasteners and workpieces. Recesses with a bottom are formed in an upper surface of a cutting insert. Part of an inner wall surface of each recess curves and bulges toward a center axis of the recess. The recess is divided into first to fourth regions by a first imaginary reference plane parallel to a rotation axis of a body, and a second imaginary reference plane perpendicular to the rotation axis. The second region is on a center side and on a proximal side of the body. A tapered surface of a fastener contacts the curved surface within the second region. A center axis of the fastener inclines so a head part opposite a distal end part is closer to the center side and to the proximal side of the body than the distal end part.

Provided are a tool body of a cutting tool for indexable inserts and a round milling insert that are configured not to cause floating or rattling when the round milling insert is mounted, by keeping the contact part between the round milling insert and the tool body at a predetermined part. The tool body includes a recessed portion provided so that only one of a plurality of protrusions is fitted thereto, the plurality of protrusions being formed in the round milling insert so as to protrude in the radial direction, wherein the recessed portion has both inner surfaces thereof formed of curved surfaces in such a manner that the distance therebetween gradually decreases toward a depth portion, at the contact area between the recessed portion and said protrusion fitted thereto out of the plurality of protrusions. The round milling insert mounted onto such tool body includes a plurality of protrusions formed so as to protrude in the radial direction, any of the plurality of protrusions being able to be fitted into a recessed portion provided on a mounting seat of the tool body, wherein each of the protrusions has both outer surfaces thereof formed of curved surfaces in such a manner that the distance therebetween gradually decreases toward a tip of the protrusion, at the contact area between the protrusion and the recessed portion into which the protrusion is fitted.

A round cutting insert for a milling tool having a center axis and a neutral plane extending perpendicularly thereto. The round cutting insert includes a circumferential side surface surrounding the center axis between upper and lower round main surfaces. An upper cutting edge is formed along the intersection of the upper round main surface and the side surface. A plurality of elongated support grooves are arranged in the side surface. Each elongated support groove has a bottom surface extending in a lengthwise direction with opposite flank surfaces converging toward the bottom surface and extending in parallel with the lengthwise direction of the elongated support groove. The lengthwise direction of each elongated support groove forms an acute angle with the neutral plane as seen in a side view. At least one of the opposite flank surfaces of each elongated support groove is configured as a side support surface.

A cutting blade having a plurality of different coatings on surfaces thereof, including an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, wherein the upper surface intersects the side surface to form at least one cutting edge unit, the cutting edge unit includes a main cutting edge and a secondary cutting edge, the upper surface includes at least one set of cutting planes, the cutting planes include a main cutting surface and a secondary cutting surface, the main cutting surface intersects the side surface to form the main cutting edge, the secondary cutting surface intersects the side surface to form the secondary cutting edge, a main coating is provided on the main cutting surface, a secondary coating is provided on the secondary cutting surface, and the main coating and the secondary coating are independent from each other.

A single-sided three-way indexable milling insert for feed milling operations, includes a positive basic shape, a rake surface, a peripheral surface including side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has a cutting edge including exactly three main cutting sub-edges and three secondary cutting sub-edges. 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.F≥0.30.