A cutting insert has an upper surface having a long side, a short side, a lower surface, a lateral surface and a through hole. The lateral surface has a first lateral surface. The first lateral surface has a first plane that is overlapped with a central axis of the through hole in a front view and is parallel to the central axis, a second plane that is located closer to the short side than the first plane and is parallel to the central axis, a third plane that is located more away from the short side than the first plane and is parallel to the central axis, and a first inclined surface that is located between the second plane and the upper surface and comes closer to the central axis as coming closer to the long side. The first inclined surface is located away from the first plane.

A rotary tool may include a holder and a cutting insert. The cutting insert may include an upper surface including a first upper side, a lower surface including a first lower side, and a lateral surface. The lateral surface may include a first lateral surface, a second lateral surface, and a third lateral surface. The first upper side may include a first end. The first end may be located closer to the third lateral surface than the second lateral surface. The first lower side may include a second end. The second end may be located closer to the second lateral surface than the third lateral surface. In a front view of the upper surface, the first lateral surface may include a tip region surrounded by the first end and the second end, and the tip region may be recessed toward the rear end.

A milling tool includes a cutting insert, a holder, a fastener and a shim. The fastener forms a first channel cooperatively with the cutting insert. The first channel is configured to direct coolant towards a top side of the insert. In order to better prevent thermal fatigue of the cutting insert under milling conditions, the shim includes a second channel configured to direct coolant towards a clearance side of the cutting insert. A method of using a milling tool and a milling process are also provided.

A cutting insert has an upper surface, a lower surface and a lateral surface. The upper surface has a first upper side, and a second upper side. The lower surface has a first lower side and a second lower side. The lateral surface has a first lateral surface, a second lateral surface, and a third lateral surface. The first lateral surface has a first concave part having a first constraining surface having a flat shape. The second lateral surface has a second concave part having a second constraining surface having a flat shape. The third lateral surface has a convex part. The first concave part and the second concave part are separated from each other by the convex part.

A milling tool includes a tool body defining an insert pocket having a main seat floor, and lower, mid, and upper seat walls. A cutting insert having an insert body is disposed in the insert pocket. The insert body includes front and back faces, with first, second, and third main circumferential sides extending between the faces and about the circumference of the insert body. First, second, and third cutting corners are disposed between the main circumferential sides. Each of the main circumferential sides includes two side seating surfaces extending between adjacent cutting corners and having a transition corner disposed therebetween. One of the front or back surfaces engages the main seat floor. Three consecutive side seating surfaces engage the lower, mid, and upper seat wall, respectively. One of the lower, mid, and the upper seat walls or each of the side seating surfaces is generally planar, the other are convex.