A shaft portion and a blade portion provided on a side surface of the shaft portion are included, and the blade portion includes cutting blades arranged in a plurality of lines on a side surface of the shaft portion along a peripheral direction, and arranged in a plurality of stages in an extending direction of a shaft center of the shaft portion in each line. Further, the cutting blade has a radial-direction clearance angle, a tip end-side clearance angle, and a base end-side clearance angle.

Provided is a rotary milling tool capable of finishing a milled surface to produce a smooth and glossy surface. A rotary milling tool in which a plurality of chip discharge grooves (2) are provided to the outer periphery of a tip part of a tool body (1), the plurality of chip discharge grooves (2) extending from the tool tip toward the tool base, and bottom blades (5, 6) are provided to an intersection ridge part at the intersection of a rake surface (3) of the chip discharge grooves (2) and a tip flank surface (4) of the tool body (1), each of the bottom blades (5, 6) being formed integrally with the tool body (1), wherein a convex edge (7) that is convex toward a tool-axis-direction tip is formed on at least one of the bottom blades (5, 6), and the convex edge (7) is formed by the connection of a plurality of linear edges that are substantially linear.

A cutting tool includes a shaft portion and a plurality of edge region groups. The ridgeline between the first rake face portion and the first flank face portion constitutes a first cutting edge portion. The ridgeline between the second rake face portion and the second flank face portion constitutes a second cutting edge portion. As seen from the direction perpendicular to a plane tangent to the outer peripheral surface, in a state where the central axis overlaps a first end on the front end side of the first cutting edge portion, the inclination angle of the first cutting edge portion relative to the central axis is larger than the inclination angle of a straight line relative to the central axis, the straight line connecting the first end to a second end on the front end side of the second cutting edge portion.

A rotary cutting tool has a plurality of circumferentially spaced grooves, each having a plurality of cutting inserts mounted. Each cutting insert has a wave-shaped major cutting edge, a corner cutting edge, and a minor cutting edge. The cutting inserts are arranged such that, the phases of the waves of the rotational trajectories formed by the cutting inserts that are adjacent to each other in a direction along the tool rotational axis coincide with each other in one groove. Also, the rotational trajectories of at least part of cutting edge portions of at least some cutting inserts are overlapped with each other in the direction of the tool rotational axis. Accordingly, even when the cutting edge portion is used as a major cutting edge and as an inner cutting edge, it is still possible to reduce cutting load and suppress breakage.

A rotary cutting tool has a plurality of circumferentially spaced grooves, each having a plurality of cutting inserts mounted. Each cutting insert has a wave-shaped major cutting edge, a corner cutting edge, and a minor cutting edge. The cutting inserts are arranged such that, the phases of the waves of the rotational trajectories formed by the cutting inserts that are adjacent to each other in a direction along the tool rotational axis coincide with each other in one groove. Also, the rotational trajectories of at least part of cutting edge portions of at least some cutting inserts are overlapped with each other in the direction of the tool rotational axis. Accordingly, even when the cutting edge portion is used as a major cutting edge and as an inner cutting edge, it is still possible to reduce cutting load and suppress breakage.

Milling tools configured to increase surface roughness are disclosed. The tool may include an elongated body having a longitudinal axis and a plurality of cutting inserts coupled to the body and spaced along the longitudinal axis, each cutting insert having a cutting edge. In one embodiment, the cutting edges may have an orientation that is oblique to the longitudinal axis of the elongated body. Each cutting edge may have a first end having a greater cutting radius than a second end. The cutting edges may be offset from the longitudinal axis of the elongated body by an offset angle. In another embodiment, the cutting edges may have a textured or rough surface profile. For example, the cutting edges may have a mean roughness (Rz) of at least 7.5 m. The milling tools may increase the surface roughness of a milled engine bore to facilitate a subsequent rough honing process.

The present disclosure provides a cutting device. The cutting device includes a shaft, two or more gussets, two or more radial cutting members, and a circumferential cutting member. The shaft extends from a first end to a second end. The two or more gussets include at least a first gusset and a second gusset extending radially away from the shaft. The two or more radial cutting members include at least a first radial cutting member axially supported by the first gusset and a second radial cutting member axially supported by the second gusset. The circumferential cutting member is axially supported by each of the first gusset and the second gusset.