Abstract: A cutting insert comprising a cutting tip and a base insert on which the cutting tip is mounted, the cutting insert being provided with a passage PA which is formed along a boundary surface between the cutting tip and the base insert so as to extend from a boundary part, in an upper surface of the cutting insert, between the cutting tip and the base insert to another boundary part, in a lower surface of the cutting insert, between the cutting tip and the base insert.

Abstract: Provided is a fastening structure having a wide application range and a high degree of freedom of design. A fastening structure includes: a head including a first end surface and a first screw part formed on the first end surface; and a shank including a second end surface and a second screw part formed on the second end surface and threadedly engaging with the first screw part. The first end surface includes a first principal surface oriented in an axial direction of the first screw part and a first step surface oriented in a rotational direction of the first screw part. The second end surface includes a second principal surface oriented in an axial direction of the second screw part and a second step surface oriented in a rotational direction of the second screw part. The first and second principal surfaces face each other and the first and second step surfaces face each other when the first screw part threadedly engages with the second screw part.

Abstract: Provided is a fastening structure having a wide application range and a high degree of freedom of design. A fastening structure includes: a head including a first end surface and a first screw part formed on the first end surface; and a shank including a second end surface and a second screw part formed on the second end surface and threadedly engaging with the first screw part. The first end surface includes a first principal surface oriented in an axial direction of the first screw part and a first step surface oriented in a rotational direction of the first screw part. The second end surface includes a second principal surface oriented in an axial direction of the second screw part and a second step surface oriented in a rotational direction of the second screw part. The first and second principal surfaces face each other and the first and second step surfaces face each other when the first screw part threadedly engages with the second screw part.

Abstract: A cutting insert comprising a cutting tip and a base insert on which the cutting tip is mounted, the cutting insert being provided with a passage PA which is formed along a boundary surface between the cutting tip and the base insert so as to extend from a boundary part, in an upper surface of the cutting insert, between the cutting tip and the base insert to another boundary part, in a lower surface of the cutting insert, between the cutting tip and the base insert.

Abstract: A cutting insert is used in a cutting edge replaceable rotary cutting tool. The cutting insert includes a first cutting edge formed on an intersecting ridge portion between a first end surface of two opposite end surfaces and a circumferential side surface, and a first depressed portion formed along a part of the first cutting edge. The first depressed portion is provided to form a larger rake angle at the first cutting edge than that at a part not having the first depressed portion of the first cutting edge.

Abstract: A cutting insert is used in a cutting edge replaceable rotary cutting tool. The cutting insert includes a first cutting edge formed on an intersecting ridge portion between a first end surface of two opposite end surfaces and a circumferential side surface, and a first depressed portion formed along a part of the first cutting edge. The first depressed portion is provided to form a larger rake angle at the first cutting edge than that at a part not having the first depressed portion of the first cutting edge.