A screw and method for the mounting of boards/planks, in particular fiber cement planks, on a support of wood. The screw comprises milling wings and a first thread between the milling wings and the tip, and a second, larger thread with smaller pitch between the milling wings and the screw head.

A building structure including a first building member and a second building member may be connected by a plurality of fasteners, each fastener having a head, a threaded portion having a through hardness of between HRB 70 and HRC 40, a thread-forming portion of at least HRC 50 hardness enabling the fastener to form threads in at least the second steel building member, and a fluted lead portion of at least HRC 50 hardness with a nominal diameter between 70 and 95% of major diameter, such that the fastener is capable of providing a ratio of strip torque to thread-forming torque of at least 3.0 and a ratio of strip torque to drive torque greater than 6.0 when the second steel building member having a thickness of 0.25 inch and the fluted lead portion having at least one diameter within nominal diameter between 80 and 98% of major diameter.

A fastener including a chisel point that pre-bores a hole in a work piece to prevent damage to the work piece as the fastener advances. The fastener can include a head, a shaft and a chisel brake point formed at an end of the shaft. The chisel brake point can include first and second opposing inclined surfaces disposed at an angle of about 80° to about 150° relative to one another. A thread can begin adjacent the chisel brake point and form an extension of an inclined surface and/or a chisel edge. The chisel brake point can scrape material from a work piece while pre-boring a hole. The material can be transferred to the thread, and subsequently fed up the thread, out of the pre-bored hole. The chisel brake point can also selectively retard advancement of the fastener into the work piece. Methods of installing the fastener also are provided.

A flooring screw comprises a screw head, a screw shank connected with the screw head, and a cone connected with screw shank. The screw shank includes a first shank section connected with the screw head, a second shank section connected with the cone, a first thread formed on the first shank section, a second thread extended from the cone to the second shank section and running helically along a direction opposite the direction of the first thread, and a third shank section between the first shank section and the second shank section. The third shank section includes a plurality of peaks protruding outward radially and a plurality of troughs formed between the peaks and recessed radially with respect to the peaks. The peaks and the troughs form an unsmooth surface on the third shank section.

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 quick fastening screw includes a head, a shank with spirally-disposed thread convolutions, and a drilling portion. Each thread convolution has at least three flank sections and at least three arc sections each formed between any two adjacent flank sections. Two ends of each arc section and the flank sections adjacent to the arc section are respectively intersected to thereby form two joints. Between the two joints is formed a curved cutting portion which forms a radian not more than a quarter of a maximum thread radius so that each curved cutting portion becomes sharp to cut quickly, speed up a screwing operation, decrease the friction between the thread convolutions and a workpiece, and reduce the resistance and torque. The non-circular thread convolutions also receive cut debris efficiently and prevent the cracking of the workpiece caused by the undue accumulation of the debris.

A wood screw structure comprises a screw head section, a rod section, a first screw thread and a plurality of crushing rib units. The rod section is sequentially integrally formed from the screw head section and comprises a first rod portion connecting the screw head section, a second rod portion, a third rod portion, and a tapered portion extending and tapering outwardly from the third rod portion. The first screw thread is disposed spirally and is protruded on an outer peripheral surface of the tapered portion, the second rod portion and the third rod portion. The crushing rib units are disposed spirally and protruded around the outer peripheral surface of the third rod portion and the tapered portion, and each of the crushing rib units includes a plurality of crushers protrudingly disposed on a rib body. A first discharge gap is formed between the crushers.

A facade panel screw for the optimized fastening of facade panel elements on a substructure has a head with very large diameter D.sub.K, a substantially cylinder cross-sectional shaft, which is at least partially provided with a thread (nominal diameter D.sub.S) and a conical tip comprising a tip angle γ. The thread extends continuously from the shaft to the tip. It is characterizing that the tip angle γ is 45°+/−10°, the thread is embodied at least in a two-threaded manner, the head diameter D.sub.K is embodied at least twice as large as the nominal diameter D.sub.S; and the facade panel screw does not have a drill tip. Such a facade panel screw is used in a fastening arrangement, which comprises a load-bearing component (substructure) and a facade panel. Due to its design, the facade panel screw is able to simplify the fastening of the facade panel and to at least partially correct an inclined positioning in response to the installation.

A method for forming a stop flange on a self-tapping screw includes locating a shank of a self-tapping screw between two threading dies, fixing one of the two threading dies and moving the other one of the two threading dies to work the shank, the external thread forming section of each of the threading dies performing threading to form an external thread on the shank, inserting the insert and the recessed corner of each of the threading dies into a top of the external thread to form a groove in the shank, and the insert of each of the threading dies gradually squeezing downward an extruded portion that is formed during formation of the groove to form a stop flange on the shank. Thus, the shank is integrally formed with the stop flange, to stop an excessive movement of the external thread.

A screw having the following successive functional sections: a threaded tip (150) shaped as a cone (A) having a double thread; a milling section (B) having a plurality of milling ribs (160) with outer diameter D.sub.F; a cylindrical shank section having the main thread with diameter D.sub.N; a thread-free shank section (D); optionally a holding thread section (E); optionally a short thread-free underhead section (F); and a head section (G) having a force engagement. The main thread (110) is guided continuously from the tip section (190) of the cone (A) via the milling section (B) to the head end of the thread-bearing shank section (C) and the ribs of the milling section (B) are arranged recessed in the thread base (140) of the continuous main thread such that the thread tips of the continuous main thread with nominal outer diameter D.sub.B project beyond the milling ribs, so that D.sub.F<D.sub.B.