To provide a multiplex screw form-rolling die, improving the durability of a screw-working part near the edge surface of the die body, and a method for manufacturing a multiplex screw bolt using the die.
In the multiplex screw form-rolling die 1 provided with the ridge part 5a of an ordinary screw threading part 5 spreading the ordinary screw and projections 6 corresponding to a slender screw thread periodically formed in a bottom part 5b of a screw threading part 5, corresponding to the positional lag between a slender screw threading part spreading the slender screw and the ordinary screw ridge; a prescribed width range from the edge surface 1a of the die body is made to be a single ordinary screw threading part 8 provided with the threading part 8a and the bottom part 8b of the ordinary screw-thread spreading to the ordinary screw and not provided with the projection part 6 corresponding to the slender screw-thread.
MIYAHARA HIROSHI
Mikio Hotta