METHOD FOR PRODUCING DIE FOR SCREW AND DIE FOR SCREW, AND METHOD FOR PRODUCING SCREW AND SCREW

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a die for screw and the die, wherein the screw for which the rotating power of a bit is acted at the right angle to the inner wall of a cross-shaped hole of the screw can be produced and also, influence of the projected part developed in the screw caused by the wearing of a male die (punch), is not received and to provide a method for producing the screw using the die and the screw.;SOLUTION: In this die, the cross-shaped hole is formed on the head part of the die and four sets of one pair of wall surfaces mutually faced from the opening hole part of the cross-shaped hole to the bottom surface, are formed as the perpendicular walls, and four ridge-line parts inclined so that the cross-shaped hole is narrower toward the bottom surface from the opening hole part, are included and the perpendicular ridge-line parts are formed toward further lower part from the lower ends of the above ridge-line parts.;COPYRIGHT: (C)2007,JPO&INPIT