The disclosure is generally directed to abrasive rotary tools capable of expanding into a substrate. Exemplary abrasive rotary tools include an expandable collet configured to expand an abrasive surface of the abrasive rotary tool. The expandable collet may be positioned proximate to a multi-planar edge of a substrate, such as a hole, and expanded into the edge to more fully and/or evenly contact the edge of the substrate. In this way, an abrasive rotary tool may more quickly and/or consistently abrade the edge.

A chuck operating apparatus includes a claw, a shifter, and a shifter drive unit. The rotatable claw has a first posture to bring the chuck into the opened state and a second posture to bring the chuck into the closed state. The rotatable shifter is brought in a first position to bring the claw into the first posture and in a second position to bring the claw into the second posture. The shifter drive unit has a shifter lever having an insertion part provided with a shifter bearing capable of being brought into contact with a side surface of an outward groove of the shifter. A roller is provided on one of the claw and the shifter in a contact position with the other to roll in a spindle axis direction and a groove is formed on the other to receive the roller when the chuck is in the opened state.

A linear friction welding machine having a two-piece collet for holding a workpiece. The two-piece collet includes first and second halves that can be separated for loading the workpiece in a transverse direction, and brought together about the workpiece and locked in place to both secure the workpiece against axial movement as well as support the workpiece against transverse loads.

A tool holder for ultrasonic machining used in a machine which supplies power via a spindle is provided with a connector received in the spindle; a conductive ring disposed on the connector and electrically connected to the spindle so as that power is configured to supply to the tool holder; a tool mounting member including an axial hole for fastening a portion of a tool; and an oscillator for producing ultrasonic vibration disposed in the tool mounting member, the oscillator for producing ultrasonic vibration electrically connected to the conductive ring so that power supplied to the oscillator for producing ultrasonic vibration is configured to produce ultrasonic vibration of high frequency. The produced ultrasonic vibration of high frequency is transmitted to the tool via the axial hole.

A linear friction welding machine having a two-piece collet for holding a workpiece. The two-piece collet includes first and second halves that can be separated for loading the workpiece in a transverse direction, and brought together about the workpiece and locked in place to both secure the workpiece against axial movement as well as support the workpiece against transverse loads.

A holding apparatus for an in particular dental workpiece includes a holding element and a fixing device. The workpiece can be fixed to the holding apparatus by a relative movement of the fixing device with respect to the holding element. The fixing device or the holding element has a split sleeve, and the inside surface of the split sleeve forms a clamping surface for the workpiece. Upon the relative movement of the fixing device with respect to the holding element, the workpiece can be braced against the holding device by the clamping surface.

A chuck operating apparatus includes a claw, a shifter, and a shifter drive unit. The rotatable claw has a first posture to bring the chuck into the opened state and a second posture to bring the chuck into the closed state. The rotatable shifter is brought in a first position to bring the claw into the first posture and in a second position to bring the claw into the second posture. The shifter drive unit has a shifter lever having an insertion part provided with a shifter bearing capable of being brought into contact with a side surface of an outward groove of the shifter. A roller is provided on one of the claw and the shifter in a contact position with the other to roll in a spindle axis direction and a groove is formed on the other to receive the roller when the chuck is in the opened state.