71546036
Jan 2, 1948
Mar 14, 1950
ROLLER TYPE EARTH DRILLING BITS, [ SCRAPE TYPE EARTH DRILLING BITS; ] BIT BREAK OUT PLATES FOR RECEIVING AND HOLDING EARTH DRILLING BITS WHILE CONNECTING AND DISCONNECTING THEM FROM DRILL STEMS; [ TOOL JOINTS FOR DRILL STEMS; ] PIPE THREAD PROTECTORS; [ EARTH DRILLING CORE BITS AND WIRE LINE RETRACTABLE CORE BARRELS THEREFOR, BOTH PROTRUDING AND NONPROTRUDING TYPES; DRILL COLLARS; DRILLING SUBSTITUTES SUCH AS TUBULAR THREADED CONNECTING ELEMENTS; ] EARTH BORE HOLE REAMERS; EARTH DRILLING PILOT BITS; [ EARTH DRILLING CORE BITS AND NON-RETRACTABLE CORE BARRELS FOR USE THEREWITH; EARTH DRILLING BASKET BITS ADAPTED TO TRAP AND REMOVE LOST NON-DRILLABLE PARTS FROM AN EARTH BORE HOLE; ] AND PARTS THEREFOR
Yarns and Threads