21 ELECTRICAL APPARATUS AND MACHINES, PARTICULARLY PORTABLE ELECTRIC TOOLS FOR BORING, BUFFING, DRILLING, GRINDING, NUT RUNNING, REAMING, SCREW DRIVING, SANDING, STUD SETTING AND TAPPING; ALSO CIRCUIT BREAKERS, ELECTRIC HAMMER DRILLS, ELECTRIC SPIKE DRIVERS, ELECTRIC HOISTS, WOOD BORING DRILLS, TRACK DRILLS, RAIL-BONDING DRILLS, STAYBOLT TAPPERS, ELECTRIC WOOD-BORING MACHINES, AND ELECTRIC WRENCHES AND PARTS THEREOF