The present invention provides a cutting tool which comprises a cutting tool insert with a tip portion of cBN material having a cutting edge formed therein and a base portion forming a sintered composition with the tip portion, and a body portion coupling the cutting tool insert with a shank of the cutting tool, wherein the cutting tool insert has a rake face and a first flank face defining the cutting edge. The rake face has a negative rake angle relative to an axis parallel to a centre axis of the body portion. A second flank face defining a further edge with the first flank face is formed such that the cutting edge and the further edge do not have a common vertex. The second flank face is tilted with respect to an axis parallel to a centre axis of the body portion by an angle greater than 0.

A toolholder includes a cutting tool mounted to a head attached to a collar at a first end of the toolholder. A shank is located at a second, opposite end of the toolholder. A central cavity extends inwardly from the first end toward the shank. A passive vibration absorber assembly is disposed within the central cavity. The passive vibration absorber assembly includes an absorber body and an absorber cap attached to the absorber body. The absorber body has a first end, a second end opposite the first end, and one or more cavities formed in the second end. The one or more cavities of the absorber body are partially of wholly filled with metal or ceramic particles or powders to provide particle damping for suppressing vibration of the toolholder.

A toolholder includes a cutting tool mounted to a head attached to a collar at a first end of the toolholder. A shank is located at a second, opposite end of the toolholder. A central cavity extends inwardly from the first end toward the shank. A viscous fluid inertia mass damper is disposed within the central cavity. The viscous fluid inertia mass damper includes an absorber body having a first end, a second end opposite the first end, a fluid reservoir formed in the damper body for containing a viscous fluid, and a plurality of apertures formed in the damper body for allowing the viscous fluid to flow from the fluid reservoir and through the apertures to suppress vibration of the toolholder. A method for suppressing vibrations in a toolholder is also disclosed.

A miniature internal boring tool including two to four shank flat surfaces and two to four integrally formed teeth. The outermost points of cutting edges of the teeth define an outer cutting diameter (OD) fulfilling the condition: 2 mm<OD<9 mm.

A tunable or tuned boring tool having a dynamic vibration absorber is provided herein. The boring tool includes a boring bar having a distal portion configured to support a tool, a proximal portion configured for attachment to a support structure of a metalworking machine, and a cylindrical body extending between the proximal portion and the distal portion, having an elongated cavity therein. The boring tool further includes a tuned or tunable absorber inserted in the cavity of the boring bar. The absorber includes an absorber mass, an annular or partially annular support circumscribing each end of the absorber mass for holding the absorber mass within the cavity, and a layer of fluid restricting material surrounding at least a central portion of the absorber mass for dampening vibration of the absorber mass. A method of forming a boring tool with a dynamic vibration absorber is also provided herein.

A tuned or tunable boring tool includes a boring bar defining an elongated cavity therein. A distal end of the boring bar is configured to support a tool or cutting insert. The boring tool further includes a dynamic vibration absorber inserted within the elongated cavity of the boring bar. The dynamic vibration absorber includes a mass that vibrates in conjunction with vibration of the boring bar. The mass has a proximal end and a distal end. The dynamic vibration absorber further includes at least one resilient proximal support positioned adjacent to and supporting the proximal end of the mass and at least one distal resilient support positioned adjacent to and supporting the distal end of the mass. The at least one proximal support and at least one distal support have a different stiffness.

There is a demand for a cutting insert capable of machining a workpiece under a wide range of cutting conditions. The cutting insert has a first portion, and a second portion protruding from a front end of the first portion. The second portion has an upper surface, a cutting edge, a rising surface, and a connecting surface having a recessed curved surface shape. The rising surface is located closer to the first portion than the upper surface, and is inclined upward with increasing distance from the upper surface. The connecting surface is located between the upper surface and the rising surface, and is connected to the upper surface and the rising surface. In a cross section having a bisecting line of a first corner, a virtual extended line of the upper surface and a virtual extended line of the rising surface intersect at an acute angle.

A non-rotating boring tool for internal turning includes a boring bar having an elongated body, a cutting element with a rake side, a relief surface and a cutting edge, and an electrically controlled vibration actuator for active vibration damping of the boring bar. Moreover, when seen in a cross-sectional plane that is perpendicular to a longitudinal axis of the elongated body and intersecting the cutting edge in a radially outermost point, straight and imaginary first and second reference lines intersect the cutting edge in the radially outermost point with the first reference line extending at an angle of 6 to the relief surface on the outside of the cutting element, and the second reference line extending between the rake side and the relief surface at an angle of 10-40 to the first reference line. The actuator is arranged with its working axis extending in parallel with the second reference line.

A boring tool has a cutting insert, a holder, and a pressing member. The cutting insert includes a base member and a cutting member. The base member includes a first side surface, a second side surface, a third side surface, and a fourth side surface. The holder includes a front end surface, a rear end surface, and an outer peripheral surface. The holder is provided with a first hole and a second hole. The first hole is opened in the front end surface. The second hole is opened in the outer peripheral surface. The holder includes a stopper. A surface defining the second hole includes a first inner side surface and a second inner side surface. The pressing member is in contact with the fourth side surface in a state in which the pressing member is disposed in the first hole.