Abstract: The invention relates to a cutting tool having twisted edge in a blade part, having a sintered compact with higher hardness and higher wear resistance than a base sintered body buried and affixed along the twisted edge, and its manufacturing method. The blade part of the cutting tool comprises the base sintered body having a twisted groove in the position of forming the twisted edge on the outer circumference, and the sintered compact of high hardness and high wear resistance applied and buried in the twisted groove and affixed to the base sintered body by sintering, and the twisted edge is formed on the sintered compact of high hardness and high wear resistance.

Abstract: A blank material for a drill having a cutting edge and a drill produced from this blank material. The blank material comprises a first blank material having a twisted groove formed on the outer circumference of a columnar base metal sinter and filled with a superhigh pressure sinter, the base metal sinter and the superhigh pressure sinter being sintered and affixed together into one body, and a second blank material composed of a base metal sinter, and the first and the second blank materials are sintered and affixed together at the end faces at superhigh pressure and high temperature. A drill is manufactured by fixing a shank material to the blank material, and forming a twisted cutting edge and a front edge part continuing therefrom, the cutting edge being formed on the superhigh pressure sinter on the first blank material and the front edge part being formed on the second blank material.

Abstract: The invention relates to a cutting tool having twisted edge in a blade part, having a sintered compact with higher hardness and higher wear resistance than a base sintered body buried and affixed along the twisted edge, and its manufacturing method. The blade part of the cutting tool comprises the base sintered body having a twisted groove in the position of forming the twisted edge on the outer circumference, and the sintered compact of high harndess and high wear resistance applied and buried in the twisted groove and affixed to the base sintered body by sintering, and the twisted edge is formed on the sintered compact of high hardness and high wear resistance.

Abstract: This invention relates to a nicked cutting tool suitable for cutting fiber-reinforced composite materials. It has an even number of twisted grooves and lands on the cutting part and the lands have nicks thereon. The nicks are preferably designed so as to incline to the longitudinal axis of the tool, and the nicks on two lands adjacent to each other in the circumferential direction incline in opposite directions to the longitudinal axis of the tool. It is possible to design the nicks so as to incline with regard to the tangent of the helix line of the twisted grooves, and in this case, the nicks on two lands adjacent to each other in the circumferential direction incline in opposite directions with regard to the helix line. In the rotation of the tool, the lands having nicks inclining in opposite directions contact alternately with the workpiece, and the fibers of the workpiece are thereby cut securely, and the shavings are discharged smoothly. The heat generated when cutting can also be dispersed.

Abstract: A nicked cutting tool enables high speed cutting in cutting process of advanced materials such as compound materials. The nicked cutting tool has a cylindrical main body with one end forming a cutting part and the other end a shank part to be mounted on a rotary driving means, and its base body is of cemented carbide. The cutting part comprises an even number of spiral twisted grooves formed on the circumferential face, lands formed between the twisted grooves, cutting edges along one edge of each land which are of sinter of high hardness nad high wear resistance and fitted and unified by sintering to the base body, plural nicks disposed on the lands and sharp outer edges formed between the nicks on the lands.