A rotary cutting tool includes a replaceable cutting head and a tool holder. The replaceable cutting head includes a forward cutting portion and a rearward mounting portion. The mounting portion includes a male coupling member that includes a straight external thread. The tool holder includes a female coupling member that includes a conical internal thread. When the rotary cutting tool is in a locked position, the external thread is threadingly engaged with the internal thread.

The objective of the present invention is to provide a cutting insert which reduces cutting load and can be accurately positioned at a coupling part of a cutting tool even if cutting edges are broken or deformed. To this end, the cutting insert of the present invention includes an upper surface, a lower surface, a plurality of lateral surfaces connecting the upper surface with the lower surface, and a plurality of upper cutting edges formed between the plurality of lateral surfaces and the upper surface. In addition, the cutting insert coupled with the coupling part of the cutting tool includes: first and second upper cutting load reducing portions formed on the upper surface and provided at each side coming in contact with first and second upper cutting edges of the plurality of upper cutting edges facing each other so as to reduce the cutting load; and a one side position setting portion provided on a first lateral surface of the plurality of lateral surfaces not coming in contact with the first and second upper cutting edges so as to set the position of the cutting insert in the coupling part.

Cutter head for accommodating multiple cutters, wherein the cutter head has a separate receptacle opening for each of the cutters, and wherein the cutter head includes clamping means for clamping the cutters in the receptacle openings. A cavity is implemented in the cutter head in the region of at least one of the receptacle openings, which is separated by a thin wall or layer from this receptacle opening, and the cavity can be filled with a fluid and a pressure can be applied thereto.

A helical blade cutter including multiple linear blades attached to an outer circumferential surface of a round body having an outer surface formed into a cylindrical circumferential surface. The blades tilt to a given helix angle α from a straight line on the outer circumferential surface parallel to a rotational central axis O. Blade attachment surfaces are formed on the outer circumferential surface of the round body at given intervals in the circumferential direction. The blade attachment surfaces tilt to an angle same as the helix angle α of the blade while tilting to a rake angle β in a direction of an elevation angle from a tangent to the outer circumferential surface. The blades are each attached to a blade attachment part through intervention of a chip holder that allows detachment of the blade.

A helical blade cutter including multiple linear blades attached to an outer circumferential surface of a round body having an outer surface formed into a cylindrical circumferential surface. The blades tilt to a given helix angle α from a straight line on the outer circumferential surface parallel to a rotational central axis O. Blade attachment surfaces are formed on the outer circumferential surface of the round body at given intervals in the circumferential direction. The blade attachment surfaces tilt to an angle same as the helix angle α of the blade while tilting to a rake angle β in a direction of an elevation angle from a tangent to the outer circumferential surface. The blades are each attached to a blade attachment part through intervention of a chip holder that allows detachment of the blade.

Provided are a cutting insert and a tool holder on which the cutting insert is provided. The cutting insert includes a circular upper surface, a circular lower surface, a cylindrical lateral surface for connecting the upper surface and the lower surface, an upper cutting edge formed between the upper surface and the lateral surface, a lower cutting edge formed between the lower surface and the lateral surface, and a plurality of rotation-preventing parts provided at the lateral surface so as to prevent the cutting insert from rotating with respect to the tool holder. Each rotation preventing part includes an inner curved surface recessed toward the center of the lateral surface and convexly rounded so as to form concentric circles in conjunction with the lateral surface, and a stepped rotation-preventing surface parallel to the axial direction of the insert and connecting the inner curved surface and the lateral surface.

A cutting insert (20) for a milling cutter (10) is described, wherein the cutting insert (20) comprises a first main surface (22) for abutment against a stop surface (24) oriented substantially perpendicular to the direction of rotation of the milling cutter (10), a second main surface (26) which is opposite to the first main surface (22), which comprises the cutting surface, and a lateral surface (28) which connects the first main surface (22) with the second main surface (26) and which comprises the free surface. The lateral surface (28) has at least one clamping section (38) by which the cutting insert (20) is clamped in a recess (18) in a tool body (12) by means of a clamping element (40), in particular wherein the cutting insert (20) is a turning cutting insert. Furthermore, a milling cutter (10) is described.

A cutting tool includes a cutting insert having an anti-rotation stopping indent formed in a transition between a bottom surface and a side surface thereof and includes a first stop surface. The insert seat has at least one anti-rotation stop, which protrudes with respect to a side wall of the insert seat and includes a second stop surface. The anti-rotation stop is arranged to inhibit rotation of the cutting insert in the insert seat by contact between the first and second stop surfaces. The second stop surface is completely located within the anti-rotation stopping indent when the cutting insert is mounted. As seen in a section perpendicular to a common central axis, an angle of less than 180° is formed between a tangent to the second stop surface and a tangent to the first duct at a transition between the two.

[Problem] A cutting tool to which a cutting insert can be firmly fixed is provided.

[Means for Resolution] Provided is a cutting tool where a replaceable cutting insert having a hole for fixing is mountable. The cutting tool includes a main body portion, a lever, a pin, and a screw. The main body portion has a placement surface where the cutting insert is placed, a side wall coming into contact with at least one side surface of the cutting insert, a lever accommodating hole, a pin accommodating hole, and a screw accommodating hole. The screw presses a rear end portion of the pin by being tightened. A tip portion of the pin presses the lever by the rear end portion being pressed against the screw. The lever has a concave surface configured by a line segment parallel to a reference axis and, by the concave surface being pressed against the tip portion of the pin, a head protruding into the hole of the placed cutting insert presses an inner wall of the hole and presses and fixes the cutting insert against and to the placement surface and the side wall.

A drill bit for cutting formation comprises a bit body, a plurality of cutters, and a plurality of blades with pockets to accommodate the cutters, respectively. In an embodiment, the plurality of cutters comprise a substrate, an ultra-hard layer, a concave surface on the top of the ultra-hard layer, wherein the concave surface comprises a plurality of planar and curved surfaces.