METHOD FOR FORMING SCREW HOLE IN BURRED THROUGH-HOLE

摘要

PROBLEM TO BE SOLVED: To provide a method for easily working a screw hole by a press work in a projecting part having a through-hole by the burring. SOLUTION: A projecting part 2 having a through-hole is worked by the burring in advance on a workpiece 1 of a metal plate. A punch 20 fitted to a spindle of a press has a threaded portion 22 on a tip part. The punch 20 is inserted in the through-hole of the projecting part 2, and press-fitted in a die 30 to transfer the thread to an inner wall part of the through-hole of the projecting part 2. The punch 20 is drawn from the workpiece 1 by rotating the punch in a reverse screw direction. COPYRIGHT: (C)2005,JPO&NCIPI