A cutting apparatus includes a cutting unit that has a spindle with an annular cutting blade mounted to a tip part of the spindle through a blade mount, and a determining unit. The determining unit has a second flow path that is connected to a first flow path in a mounter of the blade mount for causing a negative or positive pressure to act on the first flow path, a measuring device that obtains a measured value of at least one of a pressure and a flow rate in the second flow path, and a screw-engaged state determining section that determines that a screw-engaged state of a fixed nut with a boss section of the mounter where the cutting blade is disposed is defective in a case where the measured value when the negative or positive pressure acts on the first flow path indicates an abnormal value.

A cutting apparatus includes a cutting unit that has a spindle with an annular cutting blade mounted to a tip part of the spindle through a blade mount, and a determining unit. The determining unit has a second flow path that is connected to a first flow path in a mounter of the blade mount for causing a negative or positive pressure to act on the first flow path, a measuring device that obtains a measured value of at least one of a pressure and a flow rate in the second flow path, and a screw-engaged state determining section that determines that a screw-engaged state of a fixed nut with a boss section of the mounter where the cutting blade is disposed is defective in a case where the measured value when the negative or positive pressure acts on the first flow path indicates an abnormal value.

A milling apparatus has a housing, a drive shaft extending along and rotatable about an axis in the housing and an axially compressible and radially expansible washer stack on the front end of the drive shaft. A tool is held by the on the shaft. A bolt projects radially in a slot through the shaft and is limitedly axially displaceable in the shaft. An actuator element shiftable axially in the passage projects axially forward out of the drive shaft and is fixed in the bolt. A clamping assembly axially compresses and radially expands the stack so as to lock the tool to the drive shaft. A spring assembly is braced axially forward against the housing and axially rearward against the bolt. A piston axially displaceable on the drive shaft in the housing bears axially forward on the bolt.

A cutting unit includes a spindle, a spindle housing, a support flange on the front of the spindle, a cutting blade detachably supported to the support flange, and a fixing flange for fixing the cutting blade to the support flange. The support flange includes a boss portion adapted to be inserted through a central opening of the cutting blade, a flange portion for supporting one side surface of the cutting blade, and a cylindrical portion for engaging the front of the spindle. The flange portion has a suction hole opening toward the fixing flange, and the cylindrical portion has a communication hole communicating with the suction hole. The communication hole is connected to a vacuum source through a rotary joint fixed to the spindle housing so that communication between the communication hole and the vacuum source is selectively made by an on-off valve.