A spindle device is mountable with a tool holder, and includes a rotating spindle rotatably mounted to a spindle main body and extending axially to have an axial end surface. A contactless power transmission module is disposed on a flange end surface of the spindle main body and an outer peripheral wall of the rotating spindle for supplying power. An electrically connecting module includes two conductive units each disposed in the rotating spindle and electrically connected with the power transmission module. Each conductive unit has an electrically conductive post extending axially and exposed from the axial end surface for conducting the power to the tool holder.

A machine tool and a control apparatus thereof include an amplitude control unit to control the amplitude of reciprocal vibration by a vibration unit. The amplitude control unit is configured to reduce the amplitude of the reciprocal vibration by the vibration unit as a cutting tool is fed in a feeding direction when the cutting tool reaches a predetermined cutting tool work stopping position on a workpiece in the feeding direction (Z-axis direction) to prevent the cutting tool from cutting the workpiece beyond the cutting tool work stopping position.

A machine tool and a control apparatus thereof include an amplitude control unit to control the amplitude of reciprocal vibration by a vibration unit. The amplitude control unit is configured to reduce the amplitude of the reciprocal vibration by the vibration unit as a cutting tool is fed in a feeding direction when the cutting tool reaches a predetermined cutting tool work stopping position on a workpiece in the feeding direction (Z-axis direction) to prevent the cutting tool from cutting the workpiece beyond the cutting tool work stopping position.

A spindle device is mountable with a tool holder, and includes a rotating spindle rotatably mounted to a spindle main body and extending axially to have an axial end surface. A contactless power transmission module is disposed on a flange end surface of the spindle main body and an outer peripheral wall of the rotating spindle for supplying power. An electrically connecting module includes two conductive units each disposed in the rotating spindle and electrically connected with the power transmission module. Each conductive unit has an electrically conductive post extending axially and exposed from the axial end surface for conducting the power to the tool holder.

A resonant frequency dampened through-coolant machine tool for selective mounting to machining systems for precision vibration free machining and has an elongate tool body. An internal dampening chamber is defined within the machine tool body and contains a resonant frequency dampening mass that is moveable within the dampening chamber. Axial and diametrical tunable dampening devices support the dampening mass in spaced relation with internal walls of the dampening chamber. A tuning piston is moveable within the machine tool body and has a tuning flange that is disposed in contact with one of the axial tunable dampening devices. The tuning piston has a pair of oppositely angulated surfaces that are selectively engaged by angulated drive heads of adjustment screws that are supported by threaded openings of the tool body and are rotated to selectively drive the tuning piston forwardly or rearwardly for precise tuning activity. Internal components of the machine tool define a coolant fluid flow passage to conduct a jet of coolant fluid to the metal cutting interface.