PURPOSE: To provide a method and a device to form a screw hole in a plate where the number of working processes is reduced and the screw hole is rapidly formed in the plate.
CONSTITUTION: A plate 20 is arranged on a die 3 having a pair of projecting curved parts 6 on the surface of which a thread 7 is formed across a punch hole 2. A tip part 8 of a punch 4 where threads 9 are formed on the tip part 8, and a pair of recessed curved parts 10 are formed on the part corresponding to a pair of projected curved parts 6 is dropped into the punch hole 2. A tongue- shaped bent part 30 is notched in the plate 20, a pair of curbed parts 31 are formed, and threads are formed on the upper surface of the tongue-shaped bent part 30 and on the recessed surface of a pair of curbed parts 31.
MORINO JUNICHI
UEMATSU MITSUO
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