| 摘要 |
A flat drill end of a screw mainly includes a cylinder with a drill end having a thread wrapped around the cylinder, and a flat drill portion formed to the cylinder along to the drill end of the cylinder with a predetermined 5 length. The thickness of the flat drill portion is less than a half of the width of the flat drill portion for receiving more debris and ejecting the debris during the drilling so as to form a drill screw capable of drilling fast and preventing split on to the working piece. |
