23 MACHINE TOOLS AND PARTS THEREOF, COLD CIRCULAR SAWS, THREAD-CUTTING MACHINES, THREAD-ROLLING MACHINES, SKINTURNING MACHINES, MACHINES FOR DOUBLE END MACHINING, DRILLING MACHINES, AND CONVEYORS FOR THE FOREGOING MACHINE TOOLS, SAW BLADE SHARPENING MACHINES, CIRCULAR SAW BLADES, THREADING TOOLS, AND THREADING DIE TAPERS