Method of making punch-forming dies

Claim 1

IN A METHOD OF MAKING A TYPE FOR FORMING HEADER PUNCHES FOR COLD HEADING, THE STEPS OF PREPARING A BODY OF STEEL OF SUITABLE SIZE, SHAPE AND HARDNESS; FORMING A RECESS THEREIN WHICH RECESS IS COMPLETE AS TO SOME ENTIRE WALL PORTIONS THEREOF, BY PENETRATING SAID BODY WITH A FIRST MASTER PUNCH HAVING A POINT GENERALLY OF THE SHAPE OF THE DESIRED HEADER PUNCHES AND COMPRISING A CENTRAL PORTION AND RADIAL WINGS, SAID PORTION AND WINGS NARROWING OUTWARDLY FROM THE BASE OF SAID POINT, THE CENTRAL PORTION OF SAID FIRST MASTER PUNCH CONFORMING EXACTLY IN SIZE AND SHAPE WITH THE CORRESPONDING PORTION OF THE DESIRED HEADER PUNCHES, THE WINGS OF SAID FIRST MASTER PUNCH BEING OF LESSER THICKNESS THAN THE WINGS OF THE DESIRED HEADER PUNCHES; WITHDRAWING SAID FIRST MASTER PUNCH; RE-FORMING THE RECESS FORMED BY SAID FIRST MASTER PUNCH BY PRESSING THEREINTO A SECOND MASTER PUNCH TO COMPLETE SAID RECESS AS TO THE REMAINING PORTIONS THEREOF, THE POINT OF WHICH CORRESPONDS EXACTLY WITH THE DESIRED HEADER PUNCHES AS TO THICKNESS AND TAPER OF THE WING PORTIONS THEREOF, THE CENTRAL PORTION OF THE POINT OF SAID SECOND MASTER PUNCH BEING OF SMALLER SECTION THAN THAT OF THE DESIRED HEADER PUNCH; WITHDRAWING SAID SECOND MASTER PUNCH; AND HEAT TREATING AND FINISHING SAID BODY.