Method of manufacture of metal articles

Claim 1

THE METHOD OF MAKING A METAL BLANK OF OBLONG RECTANGULAR SHAPE FROM A SUBSTANTIALLY CYLINDRICAL WORKPIECE WHICH COMPRISES: (A) CUTTING A WORKPIECE FROM A LENGTH OF STOCK, (B) EXERTING PRESSURE IN AN AXIAL DIRECTION, BY MEANS OF A COOPERATING PUNCH AND DIE, ON THE OPPOSITE FACES OF THE WORKPIECE TO FORM AN ANNULAR PERIPHERAL CHAMFER AT THE CIRCUMFERENTIAL EDGE OF THE WORKPIECE WITHIN THE DIE AND TO CAUSE A FLOW OF THE METAL ALONG A LINE IN A PLANE PERPENDICULAR TO THE AXIS OF THE WORKPIECE, THEREBY ENLARGING THE WORKPIECE IN OPPOSITE DIRECTIONS IN SAID PLANE WHILE PREVENTING SUBSTANTIAL ENLARGEMENT IN TRANSVERSE DIRECTIONS IN SAID PLANE, (C) TURNING THE WORKPIECE END FOR END, (D) EXERTING PRESSURE IN AN AXIAL DIRECTION, BY MEANS OF A FURTHER COOPERATING PUNCH AND DIE, ON OPPOSITE FACES OF THE WORKPIECE TO FORM AN ANNULAR PERIPHERAL CHAMFER AT THE CIRCUMFERENTIAL EDGE OF THE WORKPIECE WITHIN THE DIE AND TO FLATTEN THE WORKPIECE ON ITS OPPOSITE FACES AND EXPAND IT LATERALLY INTO SUBSTANTIALLY RECTANGULAR FORM IN CROSS-SECTION OF GREATER LENGTH THAN WIDTH, (E) TURNING THE WORKPIECE END FOR END, (F) BY THE ACTION OF A FURTHER COOPERATING PUNCH AND DIE, INDENTING BOTH FACES OF THE WORKPIECE WHILE SQUARING THE CORNERS THEREOF, WHEREBY THE WORKPIECE IS EXPANDED TO COMPLETELY FILL THE DIE CAVITY INTO THE CORNERS THEREOF, WHILE THE FORMATION OF FLASH IS ELIMINATED DUE TO THE PREVIOUSLY FORMED CHAMFERS, (G) TRANSFERRING THE WORKPIECE TO THE FINAL DIE STATION, AND (H) PIERCING AN OPENING THROUGH THE BLANK.

Claim 2

THE METHOD OF MAKING A METAL BLANK OF OBLONG RECTANGULAR SHAPE FROM A SUBSTANTIALLY CYLINDRICAL WORKPIECE WHICH COMPRISES: (A) CUTTING A WORKPIECE FROM A LENGTH OF STOCK, (B) EXERTING PRESSURE IN AN AXIAL DIRECTION, BY MEANS OF A COOPERATING PUNCH AND DIE, ON THE OPPOSITE FACES OF THE WORKPIECE TO FORM AN ANNULAR PERIPHERAL CHAMFER AT THE CIRCUMFERENTIAL EDGE OF THE WORKPIECE WITHIN THE DIE AND TO CAUSE A FLOW OF THE METAL ALONG A LINE IN A PLANE PERPENDICULAR TO THE AXIS OF THE WORKPIECE, THEREBY ENLARGING THE WORKPIECE IN OPPOSITE DIRECTIONS IN SAID PLANE WHILE PREVENTING SUBSTANTIAL ENLARGEMENT IN TRANSVERSE DIRECTIONS IN SAID PLANE, (C) TURNING THE WORKPIECE END FOR END, (D) EXERTING PRESSURE IN AN AXIAL DIRECTION, BY MEANS OF A FURTHER COOPERATING PUNCH AND DIE, ON OPPOSITE FACES OF THE WORKPIECE TO FORM AN ANNULAR PERIPHERAL CHAMFER AT THE CIRCUMFERENTIAL EDGE OF THE WORKPIECE WITHIN THE DIE AND TO FLATTEN THE WORKPIECE ON ITS OPPOSITE FACES AND EXPAND IT LATERALLY INTO SUBSTANTIALLY RECTANGULAR FORM IN CROSS-SECTION OF GREATER LENGTH THAN WIDTH, (E) TURNING THE WORKPIECE END FOR END, (F) BY THE ACTION OF A FURTHER COOPERATING PUNCH AND DIE, INDENTING BOTH FACES OF THE WORKPIECE WHILE SQUARING THE CORNERS THEREOF, WHEREBY THE WORKPIECE IS EXPANDED TO COMPLETELY FILL THE DIE CAVITY INTO THE CORNERS THEREOF, WHILE THE FORMATION OF FLASH IS ELIMINATED DUE TO THE PREVIOUSLY FORMED CHAMFERS, (G) TRANSFERRING THE WORKPIECE TO THE FINAL DIE STATION, AND (H) PIERCING AN OPENING THROUGH THE BLANK.