Abstract: A machine tool includes a driver, a tool holder, and a locking device in the form of, for example, an alignment collar. In use, the machine tool carries a tool, such as a surface refinishing bit, which may be lowered into a workpiece bore, such as a cylinder head valve seat, and subsequently rotated by a machine spindle for resurfacing the bore. The machine tool receives a pilot shaft placed in a reference bore associated with the workpiece bore. The pilot shaft functions to ensure general alignment of the machine tool cutting axis and the refinishing surface.

Abstract: A fixturing system is provided for rigidly clamping an engine block while precisely orienting the engine block for accurate machining of selected engine surfaces during rebuilding process. The fixturing system is designed to be mounted on a working table to machine and/or inspect a variety of block surfaces. The fixturing system comprises a head stock assembly, tail stock assembly, a support member, and an indexing member. The engine block is placed between the head stock assembly and the tail stock assembly. The support member is inserted through the main bearing crankshaft bore and connects with the head stock assembly and the tail stock assembly to align and rigidly clamp the engine block to the tool table. The engine block may then be rotated to an indexed position by inserting the indexing cam bar through the cam bore and into locating slots in the head stock assembly.