| 摘要 |
A screw (3) includes two inclined cutting planes (331) formed on a drilling portion (33) of the screw (3) . A cutting edge (332) is constructed at a convergence of the two cutting planes (331) . Threaded units (34) formed on a shank (31) of the screw (3) is extended toward the cutting edge (332) and connected with one end (333) of the cutting edge (332) . The cutting edge (332) and the cutting planes (331) allow cutting debris to be swiftly and smoothly extruded therefrom into the threaded units (34) for avoiding the piling of the considerable cutting debris. Thereby, the screwing torque is reduced and the drilling speed is promoted. Preferably, the fastened screw (3) is properly sunken in the object, and the fastening operation is completed successfully. |
