Combination piercing, reaming and tapping screw

Claim 1

A SCREW FOR PIERCING A HOLE IN MATERIAL AND THEN REAMING AND TAPPING THE HOLE PRIOR TO BEING SCREWED TO A TIGHTENED POSITION IN THE MATERIAL, SAID SCREW COMPRISING AN ELONGATED SHANK TERMINATING AT ITS UPPER END IN A HEAD AND AT ITS LOWER END IN A TAPERED PIERCING POINT, SAID SHANK INCLUDING AN UPPER CYLINDRICAL PORTION ADJACENT SAID HEAD AND A LOWER CYLINDRICAL PORTION OF REDUCED DIAMETER INTERCONNECTED BY A TAPERED PORTION DECREASING IN DIAMETER FROM THAT OF SAID UPPER PORTION TO THAT OF SAID LOWER PORTION, SAID LOWER CYLINDRICAL PORTION TERMINATING IN SAID TAPERED POINT, A SCREW THREAD ON SAID SHANK EXTENDING HELICALLY DOWNWARDLY FROM SAID HEAD, SAID THREAD TERMINATING AT THE JUNCTION BETWEEN SAID TAPERED PORTION AND SAID LOWER CYLINDRICAL PORTION AND BEING GRADUALLY DIMINISHED IN HEIGHT ON SAID TAPERED PORTION TO ZERO HEIGHT AT THE LOWER END OF SAID TAPERED PORTION, SAID SHANK HAVING ON ONE SIDE THEREOF AN ELONGATED GROOVE PROVIDED THEREIN AT AN ACTUE ANGLE TO THE LONGITUDINAL AXIS OF THE SCREW EXTENDING FROM AND OPEN TO ONE SIDE OF THE SHANK SHORTLY ABOVE THE LOWER END OF THE THREAD DOWNWARDLY TO AND OPENING ON THE OPPOSITE SIDE OF SAID SHANK AND TERMINATING AT SAID TAPERED POINT, ONE SIDE OF SAID GROOVE DEFINING AT ITS LOWER END A PIERCING EDGE IN CONTIGUOUS AND TRANSVERSE RELATION TO A V-SHAPED PIERCING EDGE DEFINED BY THE OTHER SIDE OF THE GROOVE ON THE TAPERED POINT, SAID PIERCING EDGES COOPERATING TO PIERCE THROUGH THE MATERIAL UPON DELIVERY OF A HAMMER BLOW TO THE HEAD END OF THE SCREW, SAID OTHER SIDE OF SAID GROOVE BEING IN A DIAMETRICAL PLANE INCLUDING THE LONGITUDINAL AXIS OF THE SCREW AND DEFINING A REAMING EDGE ON THE PERIPHERY OF SAID LOWER CYLINDRICAL PORTION, SAID REAMING EDGE LEADING IN THE SAME DIRECTION AS THAT IN WHICH THE SCREW IS TURNED TO THREAD IT INTO THE MATERIAL AND SERVING TO ROUND OUT THE HOLE PREPARATORY FOR THE TAPPING, SAID GROOVE BEING OF SUBSTANTIALLY RIGHT ANGLE FORM IN CROSS SECTION THROUGHOUT THE LENGTH THEREOF WITH THE FIRST NAMED PIERCING EDGE LYING ENTIRELY IN A PLANE OBLIQUE TO THE AXIS OF THE SCREW.