Divided milling cutters

A two-part tool comprising a tool spindle, an inner sleeve slidable onto an securable to said tool spindle, said inner sleeve being comprised of a hydraulic sleeve comprising an inner wall, an outer wall, a substantially annular chamber defined by said walls and containing a pressure medium, an inlet to said chamber, and an outlet form said chamber a ring-shaped member surrounding and releasably secured to said hydraulic sleeve and forming together therewith an annular groove on the external surface of said inner sleeve, a first tool half releasably secured to said inner sleeve, a second tool half releasably secured to said inner sleeve, and means for positioning said second tool half on said inner sleeve in a position which is adjustable in the axial direction with respect to said first tool half, said positioning means comprising said annular groove in the external surface of said inner sleeve, a second sleeve surrounding at least part of said inner sleeve and having internal threads and a radially inwardly directed annular flange for engaging said annular groove, a third sleeve which at least partially is in sliding engagement with said inner sleeve and is provided with external threads for cooperation with said threads of said second sleeve, said second tool half being fastened to the end of said third sleeve which is adjacent to said first tool half, said inner outer walls of the inner sleeve being deflectable radially inwardly against said spindle and outwardly against said third sleeve and said tool halves, respectively, when said second and third sleeves are in threaded engagement with each other and said annular chamber is pressurized for centering and locking of said sleeves and tool halves to the tool spindle, said tool further comprising a first ring which is in said first tool half and is in sliding engagement with said inner sleeve, said first ring having an external frusto-conical portion surrounding said inner sleeve with a minute clearance therebetween, a second ring located adjacent to said first ring on the opposite side thereof with respect to said second tool half, said second ring having an internal frusto-conical surface associated with and cooperating with the external frusto-conical surface of said first ring, and means for pressing said second ring towards said first ring in the axial direction of the rings to thereby clamp the first ring and said first tool half against said inner sleeve through a wedging action between said frusto-conical surfaces.