| 摘要 |
An improved punch to punch socket on the head of a screw that extends the service life of the punch and upgrades the quality of the screw by having a recess formed on one end of the body of the punch, a punching head protruding from the center of the recess, and multiple wings are respectively extended from the sides of the punching head at a level lower than that of the head of the punch to create traces to release punching pressure to avoid deformed socket or formation of stress concentration point at the corner of the socket.
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