Abstract: Hole forming and selftapping screw of up to approximately 6 mm thread diameter for tapping into sheet metal of a thickness of up to approximately 1 mm comprising a head including a formation for receiving a tool, a thread shank and a cylinder member following thereon having a diameter less than the thread-pitch diameter of the thread shank, merging into a tapered hole forming member. The thread shank merges with the cylinder member via a taper extending over approximately four threads, a distance corresponding approximately to the four-fold sheet metal thickness. The hole forming member terminates in a convexly curved friction surface corresponding to a radius (R) of approximately 0.5 mm. The entire screw is formed in one piece of tempered steel having a tensile strength of up to approximately 1400 N/mm.sup.2, mechanically hardened steel respectively.

Abstract: A fastener clip adapted to be mounted onto a substantially plate-shaped carrier and by means of a fastening element is used for fastening of a structural part to the carrier. In order to be able to withstand sufficiently high screwing-in forces by the fastening element and in order to be able to connect the fastening element in a secure manner with the fastener clip, the fastener clip has on its leg a hollow-sleeve portion preferably with a central hole which extends over a length adjusted to the length of the fastening element.

Abstract: A portable screwdriver comprises a prime mover and, an apparatus formed as a couplable attachment, which contains the screwing tool on a drive shaft which can be connected to the prime mover. The apparatus carries a magazine receptacle for a strip-like screw magazine from which the screws are pressed under spring tension into an arcuate screw guide, where they are held between two retaining jaws until the screwing tool has taken them up and has released them for insertion purposes by swinging the retaining jaws apart. The apparatus is particularly suitable for self-tapping screws and has a narrow front cross-section, so that it can also be used at otherwise inaccessible points.The easily replaceable screw magazine comprises a plastic profile with screws guided parallel to one another and at right angles thereto. The screws can be constructed with plastic heads and jamming ribs provided on the heads.

Abstract: A portable screwdriver comprises a prime mover and, an apparatus formed as a couplable attachment, which contains the screwing tool on a drive shaft which can be connected to the prime mover. The apparatus carries a magazine receptacle for a strip-like screw magazine from which the screws are pressed under spring tension into an arcuate screw guide, where they are held between two retaining jaws until the screwing tool has taken them up and has released them for insertion purposes by swinging the retaining jaws apart. The apparatus is particularly suitable for self-tapping screws and has a narrow front cross-section, so that it can also be used at otherwise inaccessible points.The easily replaceable screw magazine comprises a plastic profile with screws guided parallel to one another and at right angles on the heads. The screws can be constructed with plastic heads and jamming ribs provided thereon.

Abstract: A self-tapping screw. The core of the screw between adjacent threads has a constricted portion, the narrowestmost point thereof lying approximately in the center between the two adjacent threads. The core is tapered expanding outwardly from the constriction to the bases of the two adjacent threads.