| 摘要 |
A screw includes a head and a shank which includes a tip end. Spiral threads are defined in an outer periphery of the shank which includes a first section including the tip end and a second section including the head. A plurality of cutting ridges extend from the outer periphery of the first section of the shank so as to cut the fibers of the object and remove the debris of the object upward. The second section includes a plurality of grooves defined in the shank so as to receive the debris to prevent the debris from breaking the object. |
