Abstract: A tooling assembly (10) is disclosed having a plurality of tool holders (18, 20) for independently driven cutting tools (14, 16), the tooling assembly adapted for automatic insertion and removal from a spindle assembly (12). The plurality of cutting tools (14, 16) are disclosed as arranged to be able to simultaneously machine concentric round features on a workpiece (8), such as a valve stem guide bore (9) and valve seat (7). The tooling assembly (10) includes inner and outer tool bodies (30, 24) rotatably mounted together, each carrying a tool holder (20, 18), the tool bodies (30, 24) rotated at different speeds. A coupling arrangement for the tooling assembly includes an outer draw bar (82) moveable to couple the tooling assembly (10) to the spindle assembly (12), and an inner draw bar (84) separately coupled to moveable element (20) to enable independent axial advance of one of the cutting tools (14) by axial movement of the inner draw bar (84) and coupled moveable element (20).

Abstract: A tool coupling arrangement is disclosed for a tooling assembly (10) adapted for automatic tool insertion into a spindle assembly (12), the tooling assembly (10) having an axially moveable element (20) for causing movement independently of the spindle assembly (12). In the particular disclosed applications, a pair of cutting tools (14, 16) are provided to simultaneously machine concentric features on a workpiece (8), disclosed as a valve stem guide bore (9) and valve seat (7) of an engine cylinder head. A first coupling arrangement secures this tooling assembly (10) after it is inserted within the spindle assembly (12), while a second coupling arrangement automatically couples the separately moveable element (20) to an inner draw bar (84) of the spindle assembly (12).