| 摘要 |
The present invention pertains to a punch (3) for forming recessed screw (4) comprising a punch body (31) and a punch head (32). Particularly, the punch head includes two square portions (321, 322) having different heights (x, y) and square sides (a, b) and intersecting at an included angle (.theta.), thereby punching the corresponding tiers of recesses (412, 413) in the socket (411) of the screw head (41) . In this manner, the screw can be facilely driven by a screwdriver (5, 6) presenting a square configuration or a uniform shape as the punch, which facilitates to reduce the problem of unfitted driving tool and increase the convenience while in operation. |
