Dowel
Dowel is a non-literary (Czech) name for a building element that is used to fasten a screw to a wall, ceiling or floor, but also to other surfaces. It is sold with different diameters in mm, according to which they are distinguished.
Literary equivalent
The literary equivalent of this word, often used in practice, has been the subject of disputes for years. As literary equivalents of this term, dictionaries suggest pin, anchor, anchor, stake, thorn, clip, countersunk pin, countersink, spacer, spreader anchor. However, each of these terms can be characterized as problematic: pin, peg, clip, anchor or anchor are rather general terms, in addition, in technology, a pin mainly refers to non-hollow objects, and an anchor (in the given context) refers to metal dowels; die is already a designation for a two-part tool for precisely forming a forging; countersunk pin is a non-hollow metal pin in engineering; spacer (in Czech, spézperka) is the designation of various spacer devices; the spreader anchor is just a metal dowel or just a plate dowel etc. In the magazine Kultúra slova 4/1997, they suggest using the term zapustka or zapustny kolík, but in the last edition of KSSJ (2003) these equivalents are not even mentioned.
Principle of operation
During fastening, the dowel acts as an elastic element distributing the force applied when screwing in the screw. After screwing in, the screw pushes the walls of the dowel, which lean against the walls of the drilled hole and thus hold the dowel in the required place. The most reliable fastening of dowels is achieved when they are used in building material that does not contain cavities and pores. In porous materials, the holding of the dowel is weaker, therefore special dowels are used for such materials (for example, with a longer contact surface). Along with the development of new building materials, special types of dowels have also been gradually developed, such as the dowel used for cardboard (does not require pre-drilling), or dowels for insulating materials, which have a special shape and thread, which improves their holding.
The present
Currently, dowels are mostly made of plastic, better quality nylon, but there are also metal variants (steel, stainless steel, brass) for which the anchor designation is used. Because there are many types of building materials and mounting options, many types of special anchors are also produced. For most types of dowels, a corresponding mounting hole must first be made, for example with a drill. In some types, by screwing in the screw, the dowel expands and attaches to the surrounding material. The fuse is the back-turned teeth or a plug formed by a dowel in the cavity. Modern types of dowels, for example for plasterboard or aerated concrete, do not require drilling a hole. They are simply hammered or screwed into the material. However, despite their name, hammer-in dowels require drilling a hole. Only then is it possible to fix them, for example, by hitting them with a hammer. The dowel makes it possible to distribute the force acting in the fastened material. The force created in this way must be equal to or higher than the force created by the pull of the object being held. When attaching very heavy materials to walls, it is sometimes necessary to spread the force over several dowels.