23 CYLINDER GRINDERS, HONING, GRINDING, AND ABRADING MACHINES AND PARTS THEREOF, EXHAUST DEVICES FOR CYLINDER GRINDERS, VALVE SPRING LIFTERS, VALVE SPRING COMPRESSORS, VALVE SPRING CLIPS, SPLIT LOCK COMPRESSORS, SPLIT LOCK CATCHERS, SPLIT LOCK REPLACERS, AND HAND TOOLS FOR USE IN REPAIRING ENGINES; HONING TOOLS AND PARTS THEREOF-NAMELY, A HEAD AND DRIVER, MANDREL ADAPTER, MANDREL, HONING STONE AND TRUING SLEEVE AND A WRENCH, USED FOR SIZING AND FINISHING HOLES AND CYLINDRICAL SURFACES AND SPECIFICALLY IN SIZING AND FINISHING DOWEL PINS, LEADER AND EJECTOR PIN HOLES AND HOLES IN EXTRUSION DIES AND LIKE STRUCTURES, AND THE CORRECTION OF OUT OF ROUNDNESS OR WARPAGE IN AN ORIGINAL HOLE OR SURFACE, MAINTAINING TRUE AXIAL ALIGNMENT WITH THE ORIGINAL BORE IN METAL AND PERFORMING SIMILAR WORK