A cutting insert based on a non-limiting aspect has a first member and a second member joined to the first member. The second member has an upper surface and a side surface adjacent to the upper surface. The upper surface includes a first side, a second side and a corner. The upper surface has a first convex portion extending toward the corner, and a second convex portion extending from the first convex portion toward the first side. The second convex portion has a first end portion and a second end portion located closer to the corner than the first end portion. A first length from the first end to the first side is less than a second length from the second end portion to the first side in a top view.

A rotary cutting tool includes a base material, a first diamond layer, and a second diamond layer. The base material includes a head portion, a body portion, and a shoulder portion defining a boundary portion between the head portion and the body portion. The first diamond layer covers the body portion and the shoulder portion and exposes the head portion. The second diamond layer covers the head portion, is provided on the first diamond layer in the shoulder portion, and does not cover the body portion.

Drilling tools and/or drill bits having notches with buttressed regions and/or notches therewithin to improve notch strength. In some embodiments, the drill/drill bit may comprise a shank comprising a cutting face, the cutting face terminating in a cutting edge. A notch may be formed along the cutting edge, which may be configured to separate chips formed by the drilling tool during operation. A buttressed region may be formed within the notch and may terminate along the cutting edge. The buttressed region may expand a size of the notch in one or more dimensions.

Drilling tools and/or drill bits having notches with buttressed regions and/or notches therewithin to improve notch strength. In some embodiments, the drill/drill bit may comprise a shank comprising a cutting face, the cutting face terminating in a cutting edge. A notch may be formed along the cutting edge, which may be configured to separate chips formed by the drilling tool during operation. A buttressed region may be formed within the notch and may terminate along the cutting edge. The buttressed region may expand a size of the notch in one or more dimensions.

An end mill has a shank and a cutting edge portion. The shank has a coolant supply path. The cutting edge portion covers an outlet of the coolant supply path and is provided on the shank. The cutting edge portion is made of a porous body.

A tool blank is substantially cylindrical and includes a front end, a rear end and a central longitudinal axis extending therebetween. At least one vein of a superhard material is formed in the blank at the front end. The vein has a depth in the axial direction and a bottom surface, a first side surface and a second side surface. Each vein has an extension in an inward direction from the periphery of the blank. For each vein, the first side surface forms an inclination angle with respect to the longitudinal axis that varies with the radial distance to the longitudinal axis of the blank over at least a major part of the extension. The inclination angle corresponds to a desired axial rake angle of a drill to be manufactured from the tool blank. A drill manufactured from such tool blank and a method for manufacturing a drill is provided.

A cutting insert may include a first surface, a second surface, a third surface and a cutting edge. The first surface may include a corner, a first side, a first inclined surface located along the corner, a second inclined surface located further inside than the first inclined surface, a third inclined surface located along the first side, a fourth inclined surface located further inside the first surface than the third inclined surface, and a protruded part located further inside than the second inclined surface and the fourth inclined surface. An inclination angle of the protruded part may be smaller than an inclination angle of the second inclined surface in a cross section along a bisector of the corner. The inclination angle of the protruded part may be larger than a third inclination angle in a cross section orthogonal to the first side.

A cutting insert may include a base body, a first part and a second part. The base body may include a first surface, a second surface, a first lateral surface, a second lateral surface, a first recess and a second recess. The first part may be located in the first recess. The second part may be located in the second recess. The first recess may include a first bottom surface, a first wall surface and a first valley line located on an intersection of the first bottom surface and the first wall surface. The second recess may include a second bottom surface, a second wall surface and a second valley line located on an intersection of the second bottom surface and the second wall surface. The first valley line may intersect with the second valley line in a perspective view of the first surface.

A rotary cutting tool includes a main body and a shank. The main body has a tip end. The shank is continuous with the main body on the side opposite to the tip end. The main body is provided with a first cutting edge having a positive twist angle, and a second cutting edge having a negative twist angle and separated from the first cutting edge. Each of the first cutting edge and the second cutting edge extends continuously from the tip end to the shank.

A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.