Abstract: In an interference fit type cutting tool according to the present invention, a head section and a shank section are fitted together by shrinkage fitting. The shank section is provided with a shaft portion and a taper portion. The head section is provided with a hole portion to be fitted on the shaft portion, and a tapered portion to be fitted on the taper portion. The hole portion and the tapered portion have an interference, and the inner diameters thereof are smaller than the outer diameters of the shaft portion and the taper portion. Two-surface restraint is established by fixing the shaft portion and the hole portion, and the taper portion and the tapered portion with the interference pressure by shrinkage fitting. A key is formed on the leading end face of the-shaft portion, a key groove is formed in the bottom face of the hole portion, and the key and the key groove are fitted together.

Abstract: In an interference fit type cutting tool according to the present invention, a head section and a shank section are fitted together by shrinkage fitting. The shank section is provided with a shaft portion and a taper portion. The head section is provided with a hole portion to be fitted on the shaft portion, and a tapered portion to be fitted on the taper portion. The hole portion and the tapered portion have an interference, and the inner diameters thereof are smaller than the outer diameters of the shaft portion and the taper portion. Two-surface restraint is established by fixing the shaft portion and the hole portion, and the taper portion and the tapered portion with the interference pressure by shrinkage fitting. A key is formed on the leading end face of the shaft portion, a key groove is formed in the bottom face of the hole portion, and the key and the key groove are fitted together.

Abstract: A cutting insert having a generally polygonal tabular form, includes a main cutting edge formed along at least one of the ridges or edges of the upper and lower surfaces which oppose each other in the direction of the thickness of the tabular form, and a face connected to the main cutting edge is formed on the flank or flanks which surround and define the upper and lower surfaces. The face includes a convex curved surface and an angle of intersection between the convex curved surface and one of the upper and lower surfaces progressively changes. The angle of intersection between the convex curved surface and one of the upper and lower surfaces progressively increases or decreases along the length of the face from the face end adjacent to a free end of the tool to a face end adjacent to the base end of the tool. In a preferred embodiment, a flat surface is disposed on each side of the convex curved surface and each flat surface intersects one of the upper and lower surfaces at a constant angle.

Abstract: The invention relates to a cutting insert. The cutting insert has a polygonal tabular body having a main cutting edge and a sub-cutting edge. A rake surface connected to the main cutting edge and the sub-cutting edge is composed of a plurality of consecutive component surfaces so as to present a multi-face surface which is curved and convex along the circumference of the body. The consecutive component surfaces are demarcated from adjacent component surfaces by edges lines L.sub.1, L.sub.2 which at their one end reach the main cutting edge. The intersection angles at which the component surfaces intersect the end surface connected to the main cutting edge are so varied in a stepped manner that the intersection angle of the component surface most remote from the nose portion is the smallest. The third component surface is curved along the circumference of the body so as to be convex outward, so that the portion of the main cutting edge associated with this component surface is also curved to be convex outward.