A method of manufacturing a drill comprises providing an elongate element defining a longitudinal direction and having, in the longitudinal direction, a front end, an intermediate section, and a rear end opposite to the front end; forming by cold forming only, at the front end, a drill tip having a cutting edge; and, forming by cold forming only, on the intermediate section, a channel extending along the longitudinal direction.

A nonloosening bolt may comprise a first bolt and a second bolt. The first bolt may have a bolt head, and the second bolt may have a threaded tip. Conversely, the first bolt may have a threaded tip, and the second bolt may have a bolt head. The first bolt may comprise an eccentric columnar portion having a small-diameter male-threaded portion at an outside circumference thereof. The second bolt may comprise a small-diameter female-threaded hole that threadedly engages with the small-diameter threaded portion. Threaded engagement between the small-diameter threaded portion and the small-diameter threaded hole may result in a constitution in which the central axes and pitches of the threaded portions at the outside circumferences of the first bolt and the second bolt are aligned. An eccentric frustoconical protrusion may be provided at the first bolt so as to fit within an eccentric frustoconical hole provided at the second bolt.

In one embodiment, a fastener includes a flexible head and a shank coupled to the flexible head. The flexible head includes a center head portion and a plurality of wing portions coupled to the center head portion. Each of the plurality of wing portions includes a contact area configured to contact a first surface of a part to be fastened. The shank includes a clip groove configured to hold a retainer clip against a second surface of the part to be fastened. The second first surface of the part to be fastened is opposite the first surface of the part to be fastened.

A screw including a shank having a tip, a rear end, which is located opposite the tip, and a longitudinal axis, which extends through the tip and through the rear end, and a screw thread helix, which is arranged on the shank, wherein the screw thread helix has a screw thread ridge for engaging into an internal screw thread groove, wherein the shank has a rearwardly facing abutment structure, which extends alongside the screw thread helix, for axial abutment of the screw thread helix. The pitch of the screw thread ridge increases as the axial distance of the screw thread ridge from the tip increases, and the screw thread helix has axial tipward play with respect to the rearwardly facing abutment structure, so as to permit axial compression of the screw thread helix.

A threaded fastener assembly for use with a nut includes a shaft head and a separate shaft. The shaft head includes a head, and an internally-threaded portion. The shaft has a first externally-threaded portion for cooperation with the internally-threaded portion of the shaft head to selectively secure the shaft to the shaft head, a second externally-threaded portion for cooperation with the nut, and an integrated nut or wrenching portion for tightening the shaft to the shaft head.

A screw including a shank having a tip, a rear end, which is located opposite the tip, and a longitudinal axis, which extends through the tip and through the rear end, and a screw thread helix, which is arranged on the shank, wherein the screw thread helix has a screw thread ridge for engaging into an internal screw thread groove. The screw thread helix has axial tipward play with respect to the shank, wherein the tipward play increases as the axial distance of the screw thread helix from the tip increases.

A screw including a shank, at least one screw thread, which is arranged on the shank, winds around the shank and protrudes from the shank, and a separate helix element, which is arranged non-monolithically on the shank, wherein the separate helix element winds around the shank, protrudes from the shank, and constitutes at least a section of the at least one screw thread. The screw further includes at least one first claw, which projects from the shank, and which has both radial and axial overlap with the separate helix element, wherein the shank and the at least one first claw are monolithic with respect to one another.

A screw includes a shank having a tip, a rear end which is disposed opposite the tip, and a longitudinal axis which extends through the tip and through the rear end. The shank consists of a first steel material. A screw thread helix is disposed on the shank and protrudes from the shank. The screw thread helix consists of a second steel material that is different from the first steel material. Both the first steel material and the second steel material are stainless steels.

A screw including a shank having a tip end and a rear end, which is located opposite the tip end, and at least one screw thread, which is arranged on the shank, which winds around the shank and which protrudes from the shank, wherein the screw thread includes a separate screw thread section, which is constituted by a separate helix element that is non-monolithically arranged on the shank. The at least one screw thread includes a thread start, which extends further towards the tip end than does the separate screw thread section, and which forms a generally helical continuation of the separate screw thread section, wherein the thread start and the shank are monolithic.

A self-sealing fastener for installation of roofing materials for creating a substantially watertight seal around fastener penetrations where roofing materials or panels are affixed to an underlying roof deck by the fasteners. Also disclosed is a method for installing the self-sealing fastener for attachment of roofing materials to an underlying roof deck with the penetrations areas or holes created by the fasteners being substantially sealed against water penetration.