| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of a large diameter braille rivet, which has sufficient strength, reduces a material quantity used and has high production efficiency, and a die used therefor. SOLUTION: In a method produce a large diameter braille rivet 20 by upsetting, in which one end part 2a of a stainless steel round bar 2 is fixed and the other end part 2b is pressed in its axial direction with a die 4, As taking D for a round bar and L for a length, the round bar having a L/D of >=2.5 is used, in the region including the abutting face on the other end part 2b of the round bar 2 in the die 4, a position deviation prevention means 4a between the round bar 2 and the die 4 in upsetting is arranged. |
