A cutting insert for drilling includes an upper surface, a lower surface formed on an opposite side of the upper surface, a side surface connecting the upper surface and the lower surface; a cutting edge formed at an intersection of the upper surface and the side surface, and a ridge portion formed to protrude upward from the upper surface to facilitate chip control. The ridge portion includes a ridge body spaced apart from the cutting edge and disposed at a central portion of the cutting insert for drilling; and a ridge extension portion extending from a vicinity of a corner of the ridge body in a direction parallel to the cutting edge.

A polygonal cutting blade having a circular arc-shaped groove in a hole includes a blade body composed of an upper surface, a lower surface and a plurality of main side surfaces connecting the upper surface and the lower surface. The blade body has a central hole penetrating through the upper surface and the lower surface, and is centrally symmetrical about a central axis of the central hole. At least one set of positioning side surface comprised of adjacent two of the main side surfaces is provided. An inner surface of the central hole has at least one circular arc-shaped groove fitting with a fastening screw for fixing the cutting blade. The circular arc-shaped groove directly faces toward an intersection of the two main side surfaces of the set of positioning side surface. A groove central axis of the circular arc-shaped groove has an offset distance from the central axis.

Provided is a cutting insert having two cutting parts that is capable of entering a workpiece more deeply and easily supports machining of a groove or hole having a small diameter in a workpiece. A cutting insert includes: a body having at least an inner surface to be fixed to a tool body of a cutting tool and an outer surface opposed to the inner surface; and two cutting parts protruding in opposite directions in a longitudinal direction of the body. The cutting part includes: a cutting upper surface; a cutting front surface; and a first cutting side surface and a second cutting side surface. A front cutting edge is located on an edge between the cutting upper surface and the cutting front surface. In a projection view of the body as seen from the longitudinal direction, the cutting upper surfaces of the two cutting parts are oriented in directions opposed to each other, and front cutting edges of the two cutting parts are disposed so as to be more away from each other as being closer to the first cutting side surface from the second cutting side surface.

There is provided a cutting insert used for both drilling and turning. The cutting insert includes an insert main body having a front surface and a rear surface, the outline shapes of which are parallelogram shapes, peripheral side surfaces disposed on four sides of the insert main body, cutting edges provided on respective intersecting ridge lines between the front surface and the peripheral side surface and between the rear surface and the peripheral side surface of the insert main body, and a hole provided in the insert main body to incline with respect to the front surface and the rear surface, the hole being usable for attachment.

A cutting crown fixing for positively locking and non-rotatable fixing of a cutting crown to a holder associated therewith of a comminuting apparatus, in particular a rotor of a comminuting apparatus, including a cutting crown, a cutting crown holder associated with the cutting crown, a screw bolt and a thread insert having a head portion and a shaft portion, wherein the thread insert has a female thread complementary to the male thread of the screw bolt and the cutting crown holder has a through passage for receiving the screw bolt, and in the installed position the thread insert is arranged in positively locking relationship in the axial and tangential direction in a holding opening of the cutting crown associated therewith. The cutting crown holder according to the invention is distinguished in that the positively locking configuration of a peripheral surface of the thread insert relative to the holding opening of the associated cutting crown extends over the entire longitudinal extent of the thread insert, wherein the thread insert is of a rotationally symmetrical configuration over the longitudinal extent of the head portion for providing an axial positively locking relationship with the holding opening and at least over a longitudinal portion has a conical peripheral surface which in the installed position corresponds to a conical receiving portion of complementary configuration of the holding opening and the thread insert in the region of the longitudinal extent of the shaft portion is of a non-rotationally symmetrical configuration for providing a rotational positively locking relationship with the holding opening.

There is provided a drill tool assembly for drilling metallic or other materials, comprising a holder having a mounting slot in which a cutting insert is positioned, and a through tool coolant supply system. The drilling tool system allows for the application of coolant to the rake surfaces of the cutting insert in a manner which facilitates enabling higher penetration rates while maintaining integrity of the cutting edges of the cutting insert. The drilling tool system comprises a holder having a rotational axis and mounting slot. A cutting insert with sides positioned adjacent the side surfaces of the mounting slot and cutting edges extending from the rotational axis is mounted in the slot. The insert includes rake surfaces adjacent the cutting edges that are positioned above the mounting slot. At least one coolant channel is disposed with at least one coolant outlet directed at the sides of the insert at a position below the rake surfaces. The coolant outlet is configured to disperse coolant in a curtain across the entire rake face of each cutting edge.

A double-sided cutting insert with orientation-assisting geometry includes identical and opposite first and second main surfaces and a peripheral surface which extends therebetween. The insert further includes a median plane located midway between the first and second main surfaces and opposite first and second clamping recesses opening out respectively to the first and second main surfaces. Projections onto the median plane of at least portions of the first and second clamping recesses are rotationally offset from one another about a central axis.

Provided are a cemented carbide having excellent plastic deformation resistance and a cutting tool in which the cemented carbide is used as a substrate. A cemented carbide includes a hard phase containing tungsten carbide particles and a binder phase containing, as a main component, an iron-group element, wherein the formula B/A≤0.05 is satisfied, where A represents the number of the tungsten carbide particles, and B represents the number of tungsten carbide particles whose number of contact points with other tungsten carbide particles is 1 or less. Preferably, the iron-group element includes cobalt, and the cobalt content in the cemented carbide is 8% by mass or more. Preferably, the tungsten carbide particles have an average particle diameter of 3 μm or more.

A drilling insert has a central portion with a central axis, and three circumferentially spaced tip portions. Each tip portion has a first axis and two diverging first cutting edges with radially outermost cutting points defining a first circle lying on a tip plane perpendicular to the first axis and having a first cutting diameter. In a view along one of the first axes, a second circle having a second diameter circumscribes the drilling insert, and the first cutting diameter is at least sixty percent of the second diameter. A cutting tool rotatable about a tool axis with a tool cutting diameter includes the drilling insert, and a second cutting insert having a second cutting edge. One of the tip portions is operative having its first axis coaxial to the tool axis, and the second cutting edge extends radially outward of the first cutting diameter.

An indexable drill insert (10) includes a top surface (12), a bottom surface (14), and a plurality of side surfaces (16) adjoining the top surface (12) and the bottom surface (14). A plurality of cutting edges (20) is formed by an intersection of a respective side surface (16) with the top surface (12). One aspect of the invention is that the top surface (12) includes a protruding portion (50) having a backwall (50a) and a segmented portion (52) extending radially outwardly with respect to the protruding portion (50) for effective chip breaking. Another aspect of the invention is that a rake surface (48) has a positive rake angle (RA) that varies along a first cutting edge section (22) of the cutting edge (20) to lower cutting force.