Abstract: The present invention pertains to a screw with a first thread section comprised of a trailing and a leading thread segments respectively spiraled on a shank and a tip section. Distinctly, the leading thread segment defines a plane surface thereon to convergently engage with an adjacently thread peak on the trailing thread segment and further constructs a thread width greater than that of the trailing thread segment while aligning the two thread segments with a correspondent profile thread height. Such configuration of the plane surface accompanies its larger thread width to enlarge a drilling channel and accordingly renders an easy entry of the trailing thread segment into an object with less friction and higher screwing speed. Additionally, the debris is partially removed through the void between the enlarged channel and the trailing thread segment to avoid cracking the object, decrease drilling torque, and enhance the fastening capability.

Abstract: The present invention pertains to a triangular shank with multiple threaded sections essentially including a head, a shank and a drilling portion. Wherein the shank has two opposite threaded sections formed in triangular and a third threaded section spiraling on the drilling portion. The third threaded section with a planar flank assists in enlarging the drilling track and providing guidance for those two threaded sections to easily enter into the object so as to efficiently extrude the debris out of the object and retain remaining debris for a better fastening effect. Further the triangular configuration results in the less contact between the screw and the object in time of screwing, thus reducing the frictional resistance and obtaining high screwing speed.

Abstract: The present invention pertains to a screw including a head, a shank having a first clockwise-threaded section and a counterclockwise-threaded section, and a drilling portion with a bottom end. Particularly, the counterclockwise-threaded section spiraling downward from the head connects to the first clockwise-threaded section by concurrently engaging their respective thread ends together. Therefore, the present invention applies the convergence of the two thread ends to efficiently guide the debris cutting by the first clockwise-threaded section and the counter force of the counterclockwise-threaded section to squeeze the debris back and share it among the threaded sections during the gradual travel of the shank through the articles, thereby reducing the drilling resistance and saving the labor imparting to the screw. Furthermore, the clockwise and the counterclockwise sections also counterbalance to steadily keep the screw buried in the articles without loosening.