Fasteners in shape corresponding to the definition of SCREWS, but with significant structural improvements (primarily the shape of the thread, tip and slot), made of high quality materials with various corrosion-resistant and aesthetic coatings.
These improvements make it possible to frequently use screws without pre-drilling holes (which greatly simplifies and speeds up the installation process of the items to be fixed), as well as to use screws for fastenings on a metal (aluminum, steel, etc.) base and in building materials (concrete, brick, etc.). P.). Such screws have significantly expanded their areas of application, significantly influenced the technology of many construction and mechanical assembly works..
Since the new screws were radically different from the traditional ones, a new term appeared in everyday life – SELF CUTTERS. This concept more accurately shows the purpose and capabilities of new screws, although today it is not legalized by the corresponding standard. Of course, the term “self-tapping” is semantically more accurate and correct, but the word “self-tapping” is more convenient phonetically, has already won positions in the Russian market and is used by the overwhelming majority of consumers.
(from German Schraube – screw)
Screw for fastening wooden parts. A tapered rod with a screw thread and a head, in which a slot (slot) is usually made for a screwdriver.
GOST 27017-86: Fastener in the form of a rod with an external special thread, a threaded tapered end and a head on the other end, forming a thread in the hole of the connected wooden or plastic product.
The definition according to GOST assumes that the screw is screwed into a previously prepared hole and is used for fastening on wooden or plastic bases. Such screws are usually made from low-carbon steels (St1, St2, St3, 10kp) without coatings, less often from corrosion-resistant steels (also from brass). Traditionally, they were and are produced mainly by the domestic hardware industry and to this day.
Detail for fastening parts of structures and machines. Anchors are laid in the building base material – concrete, masonry, etc..
Anchors are held in the building material by three basic working principles: friction, stop, adhesion.
Many types of anchors are held in the building base material through a combination of the above principles – friction and stop.
An anchor is a metal (usually steel) structure, fixed in building materials (concrete, brick, etc.) and having a threaded element (bolt, screw, stud, sleeve with metric thread) for attaching sufficiently heavy and loaded units, parts or designs.