FIELD: machine building.
SUBSTANCE: cutting tool has a holder, a cutting insert and a clamping element. Holder comprises elongated support surface extending in rear-front direction. Cutting insert has central part and three cutting parts, besides, central part has two opposite side surfaces and three located at some distance from each other mounting surfaces forming first imaginary triangle. Cutting insert is made with possibility of step-by-step movement around central axis crossing said two side surfaces. Each mounting surface intersects two of the three bisector planes containing the central axis and bisecting the respective angles of the first imaginary triangle, and cutting edge of each cutting part is located completely outside the first imaginary triangle. In each position of step-by-step movement, the clamping element is located completely behind the first vertical plane containing the central axis, and perpendicular to the rear-front direction. One of mounting surfaces is located in clamping contact with support surface.
EFFECT: higher stability of fastening of cutting insert.
22 cl, 11 dwg
