Patent ID: 7699569

Claim:
A self-drilling screw comprising: a head and a shank connecting to the head, and the shank having a plurality of threads spirally disposed thereon and a drill portion formed in its distal end; the drill portion forming a cone-shaped surface in its tip, and having a non-threaded first drilling section connecting with the shank and a second drilling section connecting with the first drilling section and having two grooves formed therein; two ends of each groove respectively connects to the first drilling section and the cone-shaped surface, and each groove forms a cutting edge on its boundary; the first drilling section being formed as an oval-shaped pillar having a predetermined diameter having two ridges extending therefrom defining a pair of guiding projections formed on opposing diametrical surfaces of said first drilling section; the diameter of the first drilling section is smaller than a diameter of the second drilling section, and the length of the second drilling section is within the range of the length of one-third drill portion and the length of two-thirds drill portion.