| 摘要 |
A self-drilling screw includes an axially extending screw shank with a leading end and a trailing end. A drill bit is secured to and extends axially outwardly from the leading end of the screw shank. At least one wing extends laterally outwardly from the drill bit transversely of the axial direction of the screw shank and spaced from the cutting edge at the leading end of the drill bit. The wing has a cutting edge facing toward the leading end of the drill bit. The wing extends outwardly beyond the outside diameter of the screw shank and forms an enlarged bore through which the shank can pass without contact with the surface of the larger bore. Each wing has a break-off groove or notch so that it can separate from the drill bit. |
