A tool for machining work pieces is disclosed. In order to provide a tool which exhibits only very small vibrations during operation, the tool body of the tool has a cavity in which a multiplicity of hollow structural elements having an outer closed shell, within which at least one solid particle or a hollow body is arranged in a freely movable manner, are accommodated.

A cutter holder has a body and a buffering assembly. The body has a specific weight. The buffering assembly is mounted in the body and has a buffering unit and an elastic unit set. The buffering unit has a specific weight that is larger than the specific weight of the body. The buffering unit and the elastic unit set are utilized for absorbing vibration. The elastic unit set has multiple Belleville washers and can be changed in scales or amounts according to practical machining conditions.

A cutter holder has a body and a buffering assembly. The body has a specific weight. The buffering assembly is mounted in the body and has a buffering unit and an elastic unit set. The buffering unit has a specific weight that is larger than the specific weight of the body. The buffering unit and the elastic unit set are utilized for absorbing vibration. The elastic unit set has multiple Belleville washers and can be changed in scales or amounts according to practical machining conditions.

A milling machine includes a spindle which is arranged to receive a tool holder and in use to cause rotation of the tool holder within the spindle. A portion of the spindle housing surrounding the tool holder is provided with at least one pair of opposing damping units.

A counterweight mechanism for a swivel arrangement includes first and second counterweights each including a seat, an axle, and two cylinders. The swivel arrangement has one end adjacent to the axle. The axle is rotatably, partially disposed in the seat. Each cylinder has a first end pivotably secured to a position proximate to the axle and a second end pivotably secured to the seat.

A balance and runout amount adjustment system for a rotary tool includes a rotary tool constituted of a tool holder mounted on a spindle, a balance determining device configured to obtain outer circumference position data of the rotary tool and to determine a mass balance of the rotary tool based on the outer circumference position data obtained, in the course of rotation of the rotary tool and a runout determining device configured to obtain shape data of the rotary tool and to determine a runout amount of the rotary tool based on the shape data obtained, in the course of rotation of the rotary tool. The rotary tool is configured to be capable of adjustment of the mass balance based on the result of the determination made by the balance determining device and capable also of adjustment of the runout amount based on the result of the determination made by the runout determining device.

A vibration reducing device for a machine tool reduces vibration generated in a tool support body supporting a tool. The vibration reducing device includes an attenuation inducing member and a pressing and fitting mechanism. The attenuation inducing member is brought into contact with the tool support body so as to generate a frictional force in a direction in which it acts as a resistance to the vibration generated in the tool support body. The attenuation inducing member has a rigidity in a direction conforming to a contact surface between the attenuation inducing member and the tool support body, which rigidity is higher than that of the tool support body. The pressing and fitting mechanism fits the attenuation inducing member to the tool support body in a pressed condition.

Anti-vibration units are provided for vibration suppression in multiple directions. The anti-vibration units may have an X-shaped structure as part of its support structure. The anti-vibration units can work for ultra-low frequency vibration isolation in three directions in a passive manner. The anti-vibration units can achieve a flexible nonlinear stiffness, which contains zero or quasi-zero stiffness, negative stiffness and positive stiffness. A smooth multi-equilibria state is also achievable. Compared with traditional spring-mass-damper (SMD) and typical QZS systems, the provided anti-vibration units can have an enhanced QZS range of larger stroke with guaranteed loading capacity, and can also achieve a lower resonant frequency with a lower resonant peak. At least some embodiments of the anti-vibration units may include a new and innovative arrangement of components that enables a more compact design than typical anti-vibration systems.