A screw includes a head and a shank extending from the head, and a hole-enlarging portion formed on the shank. The hole-enlarging portion features no thread and a substantially triangular transverse section. The hole-enlarging portion includes three inclined edges spaced from one another in the circumferential direction of the shank, and a guiding slope is formed between two adjacent inclined edges. The shank defines a longitudinal axis and is provided with a thread. Each inclined edge extends toward the head in an inclined direction relative to a horizontal axis perpendicular to the longitudinal axis. The inclined direction of each inclined edge is identical to a direction in which the thread extends toward the head.

A method of constructing a building comprising the steps of attaching a first panel to a second panel. The first panel is one of a single plenum panel and a multi-plenum panel and the second panel is one of a single plenum panel and a multi-plenum panel.

A thrust screw assembly includes a thrust screw and two threading dies for working the thrust screw. The thrust screw includes a first shank, a second shank, an external thread, and a thrust member. Each of the threading dies is provided with an external thread forming section and a flat portion forming section. In a first molding process, the first shank is worked to form the thrust member with two wing-shaped stop pieces. In a second molding process, the second shank is processed by the external thread forming section of each of the two threading dies to form the external thread on the second shank, and the two wing-shaped stop pieces is processed by the flat portion forming section of each of the two threading dies to form two flat portions on the two wing-shaped stop pieces simultaneously.

A drill bit structure of a self-tapping screw is rotated clockwise to screw with a workpiece or is rotated counterclockwise to remove from the workpiece, and the self-tapping screw contains: a head, a shank, and a drill bit. The head is configured to connect with a tool. The shank integrally extends from the head. A conical face has a tip, two arcuate grooves, and two first cutting edges. Each of the first cutting edges is formed on a connection portion of each arcuate groove and the conical face. The screw bit includes two third cutting edges, and each third cutting edge is adjacent to the tip, shapes of the two first cutting edges correspond to shapes of the two third cutting edges respectively, and heights of the two first cutting edges are not less than the conical face. Each first cutting edge has a reinforcement portion.

A self-tapping screw includes a screw head, a screw shank having a shank body extending from the screw head along an axis, a self-tapping thread extending helically around an outer peripheral surface of the shank body and having a plurality of cutting edges continuously connected to one another and extending outwardly, radially and taperingly from the outer peripheral surface of the shank body, and a supporting unit including a plurality of supporting teeth each disposed between two adjacent ones of the cutting edges, and a plurality of concave surfaces respectively adjacent to the supporting teeth and extending inwardly from the outer peripheral surface of the shank body.

A thrust screw includes a head, a first shank, a second shank, and a drilling member. The first shank and the second shank are arranged between the head and the drilling member. The second shank is provided with an external thread. The first shank is provided with a thrust member corresponding to the external thread. The thrust member includes two wing-shaped stop pieces and two flat portions. The two flat portions are formed on the two wing-shaped stop pieces respectively and correspond to the external thread. The two flat portions have an outer diameter greater than that of the external thread. The two flat portions of the thrust member stop a further screwing motion of the external thread.

A self-tapping screw includes a head portion, a lower side thereof configured with a screw rod, a front end thereof configured with a drill tail, a first thread segment formed on a front end of the screw rod above the drill tail, a second thread segment with at least two threads formed on a rear end of the screw rod immediately below the head portion, a crest angle of any one of the threads of the second screw segment being 1.15 to 1.2 times of a crest angle of any thread of the first thread segment, and a thread root diameter of the second thread segment increasing proportionally with the crest angle of the second thread segment. Whereby, the present invention provides a self-tapping screw capable of tight locking without idling.

A fastener includes a shank having a first end and a second end. The fastener also includes a thread provided on the shank, the thread including a first region having a first thread angle and a second region with a second thread angle, at least a portion of the thread having said first thread angle. The fastener also includes an arcuate detent region in the shank between respective turns of the thread.

A self-drilling screw structure comprises a screw head and a screw rod extending outwardly from the screw head. The screw rod is formed with a drill bit section at one end opposite to the screw head, a drill tail section and a screw thread section. The drill bit section comprises two first cutting edges extending helically and intersecting at a chisel edge. Two first chip flutes located at the positions respectively between the two first cutting edges and extending from the chisel edge toward the drill tail section. The drill tail section comprises two second cutting edges extending helically toward the screw thread section. Two second chip flutes located at the positions respectively between the two second cutting edges and extending helically toward the screw thread section. Each first chip flute and the second chip flute form a connection at joint between the drill bit and drill tail sections.

A self-drilling, self-tapping bone screw is described in which the bone screw has a drill tip free of threads and having a length at least as great as about the thickness of a proximal cortical bone layer, with the drill tip having opposed lands and a helical flute between each of the lands with each of the lands having a cutting edge configured to cut bone as the drill tip is rotated into the bone with the flutes conveying the bone debris away from the drill tip, where a lead thread begins to self-tap internal threads in the proximal cortical bone layer after the drill tip has drilled through the proximal cortical bone layer so as to avoid stripping the threads formed in the bone layer. A method of installation is also disclosed.