| 摘要 |
<p>A self-drilling screw consists essentially of a screw head, a rod body, a plurality of screw threads which are formed on the rod body and extended along the axis direction, and a bore tail part, wherein a drilling point is extended forward from the bore tail part by taking the central line as the center, and two symmetrical tangential sections are excavated on both sides of the bore tail part, and the tangential section forms a crumb discharge groove and a side edge and extends backwards, an end edge is formed on the placement of drilling lines between the drilling point and the two side edges, and the end edge shows concave shape, thus it makes the drilling point more protrudent, and shortens the distance of that two side edges drill the object.</p> |
