Abstract: A self-drilling screw (10) having a body (16) that includes a driving head (18) and aperture (20) at its one end and a self-drilling tap (22) at its other end. Intermediate the length of screw (10) a solid annular member (24) comprising a peripheral edge (31) separating annular surfaces (32, 33) is formed. A plurality of radially extending serrations or teeth (36) is formed on the one annular surface (32), in a circumferential pattern paralleling the turning motion of the screw (10) in its application to a thin gauge metal deck structure (44). Two sets (26, 27) of different sized threads are formed on the body (16) between the surface (32) and the tap (22). As the serrations (36) gouged or coerce the metal during the achieving of a fully driven position for the screw (10), the larger sized threads (26) bind or tap-like to an upright boss (52) formed by the puncturing of the hole, first by the smaller sized set (27) of threads and then by the larger thread set (26).