Countersunk-head screw for the attachment of accessories and hardware on a metal wall

摘要

The screw (200) has a countersunk-head (210) including a conical sub-head (212) connected to a screw shank (220) provided with a thread (221). A curved top (211) of the countersunk-head has a cavity (214) for receiving a screwing tool. The sub-head of the head is provided with a cone having conicity of 100 degrees. The thread of the shank is raised till to a junction between the sub-head and the shank. An intermediate cone (215) has another thread (216) that is raised on a surface of the intermediate cone till to another junction between the intermediate cone and the cone of the sub-head.