A cutting tool has a rake face and a flank face. The flank face is provided with a coolant supply hole. A ridgeline between the rake face and the flank face forms a cutting edge. An outer shape of the coolant supply hole in a cross section orthogonal to an axis includes a first portion facing the cutting edge, and a second portion opposite to the cutting edge when viewed from the first portion. The first portion has a concave portion extending toward the second portion. The concave portion is defined by a first side portion and a second side portion facing each other, and a bottom continuous with both the first side portion and the second side portion. In the cross section, an angle formed by a tangent of the first side portion and a tangent of the second side portion is not more than 160°.

A cutting tool has a rake face and a flank face. The flank face is provided with a coolant supply hole. A ridgeline between the rake face and the flank face forms a cutting edge. An outer shape of the coolant supply hole in a cross section orthogonal to an axis includes a first portion facing the cutting edge, and a second portion opposite to the cutting edge when viewed from the first portion. The first portion has a concave portion extending toward the second portion. The concave portion is defined by a first side portion and a second side portion facing each other, and a bottom continuous with both the first side portion and the second side portion. In the cross section, an angle formed by a tangent of the first side portion and a tangent of the second side portion is not more than 160°.

According to one implementation, a drill includes: a drill includes: a body without a back taper; and a cutting edge part integrated with the body. The body has a flow path of a cutting oil inside. The cuffing edge part has a first supply port that supplies the cutting oil toward a workpiece, The body has at least one second supply port that supplies the cutting oil to a clearance formed between a bush for positioning and the body. The bush is used by being inserted in the body.

According to one implementation, a drill includes: a drill includes: a body without a back taper; and a cutting edge part integrated with the body. The body has a flow path of a cutting oil inside. The cuffing edge part has a first supply port that supplies the cutting oil toward a workpiece, The body has at least one second supply port that supplies the cutting oil to a clearance formed between a bush for positioning and the body. The bush is used by being inserted in the body.

The invention relates to a four-edged drill having two long main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner to a chisel edge in the middle of the drill tip, and two short main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner in the direction of the middle of the drill tip. According to the invention, each long main cutting edge has an outer partial cutting edge, extending from the cutting corner as far as a shoulder, and an inner partial cutting edge, extending from the shoulder as far as the chisel edge, said inner partial cutting edge having a greater cutting height (Δx) than the outer partial cutting edge and the short main cutting edges.

The invention relates to a four-edged drill having two long main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner to a chisel edge in the middle of the drill tip, and two short main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner in the direction of the middle of the drill tip. According to the invention, each long main cutting edge has an outer partial cutting edge, extending from the cutting corner as far as a shoulder, and an inner partial cutting edge, extending from the shoulder as far as the chisel edge, said inner partial cutting edge having a greater cutting height (Δx) than the outer partial cutting edge and the short main cutting edges.

Provided is a body capable of suppressing the bending of the body during machining. A body includes: a first mounting part serving as a portion that is provided on a leading end side and has a cutting edge mounted thereon; and a second attachment part serving as a portion that is provided at a position different from a position of the first mounting part along a circumferential direction and has a guide pad attached thereto on the leading end side. One discharging groove that extends from the leading end side to a base end side and is used to guide and discharge a fluid to the base end side is formed on an outer peripheral surface of the body, and at least a part of the discharging groove is bent.

The present invention provides a material for built up edge formation having a resin block containing a high molecular weight compound having a weight average molecular weight of 5×10.sup.4 or higher and 1×10.sup.6 or lower, a medium molecular weight compound having a weight average molecular weight of 1×10.sup.3 or higher and lower than 5×10.sup.4, and a carbon.

The present invention provides a material for built up edge formation having a resin block containing a high molecular weight compound having a weight average molecular weight of 5×10.sup.4 or higher and 1×10.sup.6 or lower, a medium molecular weight compound having a weight average molecular weight of 1×10.sup.3 or higher and lower than 5×10.sup.4, and a carbon.

A drill point for machining of light alloys, such as aluminium alloys, includes a body having a front end with an apex area, a central axis of rotation and at least one cutting structure. Each cutting structure has a primary rake surface, a primary clearance surface, a cutting edge at an intersection between the primary rake surface and the primary clearance surface, and a peripheral cutting corner. The cutting edge extends radially outward from the apex area to the cutting corner. The primary clearance surface, as seen in a front end view, has a breadth that is a distance extending perpendicular to and from the cutting edge to a primary clearance surface edge, which is rotationally trailing the cutting edge. The body further has a nominal cutting radius, which is a radial distance outward from the central axis of rotation to the cutting corner, and which is at least 1 mm.