A combined structure of an arbor and an arbor seat, including: an arbor, having a first assembling portion which has at least one first hole, each first hole having a first central axis; an arbor seat, having a second assembling portion which is disposed in the axial direction, and the first assembling portion and the second assembling portion being insertably connected with each other, the second assembling portion having at least one second hole which has a second central axis, when the first and second assembling portions are connected with each other in the axial direction, each second central axis is noncoaxial and nonoverlapped with the at least one first central axis; and wherein at least one said fastener is inserted into one said first hole and one said second hole, and urges one said first hole and one said second hole in axially opposite directions.

A combined structure of an arbor and an arbor seat, including: an arbor, having a first assembling portion which has at least one first hole, each first hole having a first central axis; an arbor seat, having a second assembling portion which is disposed in the axial direction, and the first assembling portion and the second assembling portion being insertably connected with each other, the second assembling portion having at least one second hole which has a second central axis, when the first and second assembling portions are connected with each other in the axial direction, each second central axis is noncoaxial and nonoverlapped with the at least one first central axis; and wherein at least one said fastener is inserted into one said first hole and one said second hole, and urges one said first hole and one said second hole in axially opposite directions.

A rotary cutting tool includes a cutting head and a tool shank, each having an axial abutment surface and a plurality of drive surfaces. One of the two includes a locating pin, while the other includes a pin receptacle and at least one clamping through bore that opens out to the pin receptacle. The locating pin is received into the pin receptacle. The cutting head and tool shank are releasably clamped together by at least one clamping member that passes through the at least one clamping through bore and acts on the locating pin so that the drive surfaces and the axial abutment surfaces on each part abut each other.

A cutting tool assembly includes a tool body and a tool holder including a longitudinal axis around which the tool holder is configured to spin. The tool holder includes a central portion connected to the tool body comprising a fastener hole perpendicular with the longitudinal axis and configured to receive a securing fastener, wherein the fastener hole is offset from the longitudinal axis. The tool holder further includes an eccentric drive member connected to the cylindrical portion. The tool holder can optionally further include an end alignment cylinder connected to the eccentric drive member.

A tool for machining a workpiece. The tool comprises a cutting insert with a shank, which extends along a cutting insert longitudinal axis, and with at least one cutting edge, wherein at least a part of the cutting insert is made of a first material. The tool further comprises a tool holder which extends along a holder longitudinal axis and comprises on an end-face end a cutting insert receptacle for receiving the cutting insert shank, wherein the cutting insert receptacle is designed as a cup-shaped recess in the tool holder. The tool further comprises an attachment element which is fixedly connected to the cutting insert and extends in a circumferential direction around the cutting insert shank, wherein at least a part of the attachment element is made of a second material which differs from the first material. Still further, the tool comprises a fastening element for fastening the cutting insert on the tool holder, wherein, in a mounted state of the tool, the fastening element contacts the attachment element in order to fasten the cutting insert on the tool holder.

A cutting tool assembly includes a tool body and a tool holder. The tool holder includes a cylindrical portion connected to the tool body, an eccentric drive member, and a fastener hole configured to receive a securing fastener. The eccentric drive member can include a trigon portion comprising a rounded triangular cross section.