A two-part mechanical fastener comprising an elongated body with a bore slidably carrying a mandrel adapted to interferingly engage the body is described. The fastener body has one or more protuberances on its exterior surface. In an aspect, the protuberances form a thread. The fastener is adapted to form an opening in, and penetrate, a stack of two or more workpieces. To secure the workpieces in the workpiece stack and form a robust joint, the fastener body is deformed by the mandrel, expanding the body, so that a body end engages a surface of the workpiece stack and the one or more protuberances are brought into engagement with the walls of the opening. Methods of using such a fastener to secure non-ferrous or polymer-based sheet-like workpieces to one another are disclosed.

A cement board screw a high thread that begins on the tapered end, extends onto the shank and terminates at a second axial location along the shank. The high thread defines a high peripheral edge, where a leading flank and a trailing flank meet at the high peripheral edge and together define a high thread angle that is between about thirty degrees and about fifty-five degrees. A low thread begins on the tapered end, extends onto the shank and terminates substantially at a first axial location along the shank such that an axial length of the low thread is less than an axial length of the high thread. The low thread includes a leading flank and a trailing flank that meet at a low peripheral edge and together define a low thread angle that is between about fifty degrees and about seventy degrees.

A self-drilling, self-countersinking fastener is provided that includes a shaft, a countersunk head located at a first end of the shaft, and a tapered point located at an opposite end of the shaft. A thread integrally extends from the shaft and extends along at least a portion of a length thereof. The countersunk head includes a frustoconical region having a first, smaller diameter in a shaft connection region and a second, larger diameter at a second end defining an edge area of the head. A plurality of radially extending ribs are located on the frustoconical region and extend from an area of the first, smaller diameter to a respective radially outer rib end spaced radially inwardly by a distance X from the edge area of the head. A respective cutting edge is located on each of the ribs.

In a joining method for joining a first plate material and a second plate material by screwing a self-tapping screw from one direction in a state where the first plate material and the second plate material are put on top of each other, a recessed portion is formed in at least one of the first plate material and the second plate material, and in a state where the first plate material and the second plate material are put on top of each other such that the recessed portion is opened in a contacting face between the first plate material and the second plate material, the self-tapping screw is screwed from the one direction. When the self-tapping screw penetrates through the first plate material due to the screwing of the self-tapping screw, an excess part generated from the first plate material flows into the recessed portion.

A self-tapping screw includes a shank having a rear end provided with a drilling tip and an external thread. The external thread has a top formed with a stop flange. The stop flange has a diameter greater than that of the external thread. Thus, the shank is integrally formed with the stop flange by two threading dies, to stop a further movement of the external thread, and to prevent the external thread from being fed and locked excessively, thereby preventing the shank from being worn out or broken during operation.

A fastening device for reducing the time required for insertion that includes an elongated shank portion extending longitudinally between a first and a second shank end; and a head portion arranged at the second shank end, wherein the head portion includes a drive arrangement configured and arranged for receiving a rotary driving force to drive the fastening device into at least one workpiece. The elongated shank portion includes a plurality of intertwined helical ridges (plural thread starts). Preferably, the tip portion is configured and arranged to create a hole and threads by softening the material of a workpiece. Additionally, a method for creating an assembly by attaching a first workpiece to a second workpiece via the use of such a fastening device.

A method is provided for producing an adhesive screw connection between at least one upper component and at least one lower component using a flow drill screw, which penetrates the upper component at a joining point through a pre-drilled hole and is screwed together with the lower component, forming a flow-drilled hole. The pre-drilled hole in the upper component is covered by a secured cover which is first perforated by the flow drill screw before the latter penetrates into the pre-drilled hole and is then screwed together with the lower component.

Self-sealing fasteners and associated building panels, systems, and methods are provided. In one aspect, a fastener includes an elongated fastener body with an external surface extending between the first end and the second end, and a coating material disposed on at least a portion the external surface. In another aspect, a fastener includes an elongated fastener body with an external surface extending between the first end and the second end, and a polymer annulus surrounding at least a portion of the external surface of the of the elongated fastener body at or adjacent the head of the fastener.

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.

A wall nail includes a rod body, a nail head, a rotary head, and a rubber cover. The rod body has a first end portion and a second end portion opposite to the first end portion. The nail head includes a threaded rod and a drill. Two ends of the threaded rod are integrally connected with the second end portion of the rod body and the drill respectively. The rotary head is integrally formed on the first end portion of the rod body. The rubber cover covers the peripheries of the rod body and the rotary head.