Abstract: The present invention pertains to a screw for use in nonmetal objects comprising a plurality of cut-aiding portions formed by the longer and shorter cutting surfaces inclined toward opposite directions. Further, a cutting edge formed by the junction of any two adjacent cutting surfaces presents in a fastening direction of the screw. Thus, the cutting edge assists the threads to thoroughly severe and to shatter the fibers and debris of the objects, which can also be accommodated into the cut-aiding portions. Also, the ridge of the longer cutting surface aids in cutting fibers and further guides the debris out. In this manner, the present invention facilitates to enhance cutting capability for obtaining less screwing resistance, to prevent the destruction of the object and to increase the screwing speed.

Abstract: The present invention pertains to a high-speed fastening screw comprising a plurality of concavities on the threads connected in sequence in a single helix. Further, the concavities separately located adjacent to the screw head and to the drilling portion are disposed at relative positions for aligning with an imaginary line, hence efficiently cutting and severing the object fibers to enhance a screwing efficiency.