Under reamer

Claim 1

AN UNDER REAMER OF THE CHARACTER REFERRED TO INCLUDING, AN ELONGATE VERTICALLY EXTENDING TUBULAR BODY, SCREW THREADS AT THE UPPER END OF THE BODY TO RELEASABLY SECURE THE BODY WITH THE LOWER END OF AN ELONGATE STRING OF FLUID CONDUCTING DRILL PIPE, A PLURALITY OF ELONGATE CIRCUMFERENTIALLY SPACED, RADIALLY OUTWARDLY OPENING SLOTS EXTENDING LONGITUDINALLY OF THE BODY, AN ELONGATE ARM ARRANGED WITHIN EACH SLOT TO NORMALLY OCCUR WITHIN THE CONFINES OF THE SLOT, MEANS PIVOTALLY SECURING THE UPPER END OF THE SEVERAL ARMS TO THE BODY, AN ELONGATE ROLLER CUTTER ROTATABLY CARRIED BY AND PROJECTING RADIALLY INWARDLY FROM THE LOWER END OF EACH ARM TO NORMALLY OCCUR WITHIN THE CONFINES OF THE BODY AND FLUID PRESSURE OPERATED ACTUATING MEANS WITHIN THE BODY AND RESPONSIVE TO FLUID PRESSURE WITHIN THE BODY AND THE RELATED STRING OF DRILL PIPE AND OPERABLE TO PIVOT THE ARMS RADIALLY OUTWARDLY AND UPWARDLY AND SO TO SHIFT THE CUTTERS RADIALLY OUTWARDLY FROM WITHIN THE CONFINES OF THE BODY, EACH CUTTER HAVING A PLURALITY OF LONGITUDINALLY SPACED ANNULAR ROWS OF CIRCUMFERENTIALLY SPACED RADIALLY OUTWARDLY PROJECTING FORMATION ENGAGING TEETH, THE AXIAL SPACING OF THE ROWS OF TEETH AND THE CIRCUMFERENTIAL SPACING OF THE TEETH OF SAID ROWS OF TEETH ON EACH CUTTER BEING ARRANGED SO THAT WHEN THE CUTTERS ARE SHIFTED OUTWARDLY AND ARE ROTATED INTO ENGAGEMENT WITH AND ABOUT AN ADJACENT ANNULAR SHOULDER IN AN EARTH FORMATION SURROUNDING THE REAMER, THE TEETH OF EACH CUTTER ENGAGE THE FORMATION BETWEEN THE TRACKS OF THE TEETH OF THE OUTER CUTTERS AND EACH TOOTH ENGAGES THE FORMATION AT A POINT SPACED CIRCUMFERENTIALLY FROM THE POINTS OF CONTACT BY TEETH ON ADJACENT TRACKS.