CUTTING AND SLITTING TOOLS AND DISCS; CUTTING MACHINES AND PARTS THEREOF-NAMELY, SCORE CUTTERS AND HOLDERS THEREFOR, CIRCULAR CUTTERS, AND CUTTER SHAFTS; DISHED CUTTERS FOR MACHINERY AND COLLARS WITH OR WITHOUT LOCKING DEVICES COOPERATING THEREWITH; PLATE VALVES FOR INDUSTRIAL PISTON DRIVEN ENGINES, COMPRESSORS, BLOWERS AND SCAVENGING PUMPS; VALVES FOR USE WITH MACHINES AND COMPRESSORS; CONCENTRIC PLATE VALVES FOR HIGH-SPEED COMPRESSORS; SCAVENGING VALVES FOR INDUSTRIAL DIESEL ENGINES; AND KN...