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 shock-absorbing article may be mounted on a drill bit by sliding the drill bit through one or more holes in the article. The article may have a mass of shock-absorbing material with a void extending through the mass. The void may be substantially the same diameter as, or a greater diameter than, the drill bit. The mass may be substantially a circular cylinder and have a center-of-mass that is within the void of the disk. The mass may comprise indicia that indicates the size of a compatible drill bit. The shock-absorbing material may be an elastomer. The article may further comprise a washer having a washer hole, and the washer hole may be substantially a circular cylinder.

An embedded damping vibration attenuation turning tool holder for deep cavity machining and a method includes a tool holder and a damper; one end of the tool holder is connected with a turning blade; a side surface of the tool holder is provided with a square cavity; the damper is in interference fit in the square cavity; the damper includes a mass block, an elastic member and piezoelectric ceramic; at least one surface of the mass block that is in contact with an inner wall of the square cavity is connected with the piezoelectric ceramic; the elastic member is arranged between the piezoelectric ceramic and the mass block; and the piezoelectric ceramic is used for generating interaction with the inner wall of the square cavity under a vibration action of the tool holder, so as to absorb the vibration to generate electric energy.

A tool holder, for a tool assembly, comprising a tubular element having a cavity and a central axis; a damping mass arranged within the cavity and movable radially with respect to the central axis and relative to the tubular element; an adapter having a rear part fixed to the tubular element, and a front part for connection to an end effector of the tool assembly, the rear part comprising an opening, and the damping mass is at least partly received in the opening with a radial clearance; and an elastic element positioned between the adapter and the damping mass, the elastic element being arranged to support the damping mass and to damp radial vibrational movements of the damping mass relative to the tubular element, and the elastic element comprising a front surface substantially perpendicular to the central axis and a rear surface substantially perpendicular to the central axis.

The holder includes a body having a rod shape extending from a first end surface to a second end surface and including a large-diameter portion which is a recess extending from the first end surface, a weight located in the large-diameter portion, a ring-shaped first elastic member, and a lid press-fitted into the large-diameter portion from the side of the first end surface. The inner peripheral surface of the large-diameter portion includes a first region located on the side of the first end surface and a second region located closer to the second end surface than the first region. The first elastic member comes into contact with the inner peripheral surface of the large-diameter portion in the second region to fix the weight to the inner peripheral surface. The surface roughness of the second region is greater than the surface roughness of the first region.

A cutting tool assembly having a longitudinal axis establishing upward and downward directions, includes a Y-axis parting adaptor mounted onto a holder. The parting adaptor has an insert pocket including a base jaw configured to support a cutting insert. The holder has a holder head portion and a shank portion. The holder head portion has an adaptor pocket in which the parting adaptor is mounted. If the holder shank cross-sectional shape is square or rectangular the forwardmost cutting edge is directly above the forwardmost holder shank surface, and if the holder shank cross-sectional shape is round and a centrally extending holder shank axis extends to the forwardmost cutting edge.