Fixed joints widely used in mechanical engineering are divided into two types: detachable (performed mainly with the help of threaded fasteners - bolts, screws, studs and nuts) and one-piece (performed by various types of rivets, welding, soldering, gluing).
Threaded and riveted joints are widely used in all branches of engineering, and they account for up to 35% of the total labor intensity of assembly work. The range of used fasteners is large and tends to grow. This is due to the fact that the creation of new progressive products, usually more expensive, does not exclude the possibility of using traditional cheap fasteners (bolts, screws, nuts, rivets, washers) in simple light-loaded assemblies that guarantee the required consumer qualities of machines. For example, the US industry produces more than two million types of fasteners, including more than 50 thousand standard (according to US terminology), for a total amount of several billion dollars a year.
The classifier of state standards refers fasteners for general machine-building use to the GZ group, which includes the following classes: G31 - bolts; G32 - screws, studs; GZZ - nuts; G34 - rivets; G36 - washers, cotter pins; G37 - pins; G38 - other industrial hardware. At present, many types of progressive fasteners have been developed and mastered in various branches of the machine-building complex, which are not in the State Standards Classifier. A variety of fasteners in terms of design, technological, functional and other features makes it difficult to exhaustively classify and describe them. However, all fasteners can be divided into five groups. The classification is based on one of the most characteristic features that determined the name of each group, namely: fasteners for mass use; high-strength threaded fasteners; fasteners for one-sided setting and shockless riveting; fasteners for high-life and hermetic connections; fasteners for joining polymer composite materials.
The conditionality of the proposed classification lies in the fact that in each group there is a certain range of fasteners that can be attributed to another group. For example, in the group of fasteners for one-sided setting and impactless riveting, some designs of bolt rivets are designed for high-life joints or for joints of composite materials. At the same time, each of the groups includes fasteners of several classes according to the State Standards Classifier. For example, the group of high-strength fasteners includes classes of bolts, screws, nuts, and the group of high-strength fasteners includes classes of bolts, rivets, etc.
However, the proposed classification allows designers and technologists to relatively easily understand a wide variety of fasteners and take into account their specific features when designing and developing technological processes for assembling detachable and one-piece joints, and will also assist specialists involved in the design and organization of specialized production of fasteners.
Correctly naming a fastener is often very difficult. What's this? Bolt or screw, anchor or dowel. Considering the wide variety of this class of products and the complexity in their correct name, we turn to GOST, which regulates the names and terms.
Below are some of the most commonly used terms and definitions in accordance with GOST 27017-86 for fasteners and their structural elements.
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A fastener in the form of a rod with an external thread at one end, with a head at the other, forming a connection with a nut or a threaded hole in one of the connected products. |
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A fastener for forming a connection or fixation, made in the form of a rod with an external thread at one end and a structural element for transmitting torque at the other. Note: The structural element of the torque-transmitting screw may be a slotted head, a knurled head, or, in the absence of a head, a slot in the end of the rod. |
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A fastener in the form of a rod with an external special thread, a threaded conical end and a head at the other end, forming a thread in the hole of a wooden or plastic product to be joined. Note: The special thread has a triangular pointed profile and a large root width compared to the width of the tooth. |
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Fastener in the form of a cylindrical rod with external threads at both ends or along the entire length of the rod. |
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Fastener in the form of a cylindrical or conical rod for fixing products during assembly. |
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A fastener with a threaded hole and a structural element for transmitting torque. Note: A structural element of a nut for transmitting torque can be a polyhedron, knurling on the side surface, end and radial holes, slots, etc. |
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A fastener with a hole placed under the nut or head of a bolt or screw to increase the bearing surface and/or prevent them from self-loosening. |
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A fastener in the form of a wire rod of a semicircular cross section, folded in half to form a head. |
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Fastener in the form of a smooth cylindrical rod with a head at one end, which serves to obtain a permanent connection due to the formation of a head at the other end of the rod by plastic deformation. |
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A bolt whose smooth shank diameter exceeds the nominal thread diameter. |
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Bolt, the head of which is made in the form of a movable part of the swivel joint. |
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A bolt, the diameter of the smooth part of the rod of which is determined from the condition of ensuring the shear operation of the connection. |
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Bolt with a special shape of the head, which is used to fasten the equipment to the foundation. Note: The special shape of the head may represent the extended legs of the slotted part of the rod, the bent part of the rod, etc. |
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A screw whose smooth shank diameter is smaller than the inside diameter of the thread. |
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A screw that forms a special thread in the hole of one of the plastic or metal products to be joined. |
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Self-tapping screw with drill shape end. |
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A screw with a specially shaped end used to fix products relative to each other. Note: Special end shape can be cylindrical, conical, flat, etc. |
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Pin of cylindrical section with a longitudinal groove along the length, made of spring steel. |
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Hexagonal nut with radial slots for the cotter pin on the side of one of the end surfaces. |
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Hexagonal nut, part of which is made in the form of a cylinder with radial slots for the cotter pin. |
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Nut with spherical and flat end surfaces and blind threaded hole. |
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Nut with flat protrusions for torque transmission. |
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Washer with a flat bearing surface. |
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A split round washer, the ends of which are located in different planes, which serves to prevent self-unscrewing of fasteners during its elastic deformation under load. |
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A washer used to prevent self-unscrewing of fasteners using structural elements. Note: The structural elements of the washer are paws, socks, teeth, etc. |
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Rivet with a rod of tubular section. |
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A rivet, the end part of which has a tubular section. |
Elements of fasteners
Kernel. Part of a fastener that enters directly into the holes of the products to be joined or is screwed into the material of one of them.
Fastener head. A part of a fastener having a rod that serves to transmit torque and (or) form a supporting surface.
Bolt head. The smooth part of the shaft of a bolt, cylindrical, oval or square, directly adjacent to the head and used to center the bolt or prevent it from turning.
Fastener collar. A protrusion on the bearing surface of a polyhedral nut, bolt head or screw, made in the form of a cylinder or a truncated cone with a diameter greater than the diameter of their circumscribed circle.
Supporting protrusion of the fastener. An annular protrusion on the bearing surface of a polyhedral nut or bolt head whose diameter is less than the spanner size.
Note: Wrench size refers to the distance between opposite faces of a polyhedral nut or bolt head, screw, measured in a plane normal to their axis.
Fastener slot. A recess of a special shape in the end of the head of a bolt, screw or screw, in the end of a headless set screw, along the generatrix or in the end of a nut.
Note: The shape of the slot can be hexagonal, cross-shaped, in the form of a through or blind slot, etc.
Bolt spike. A protrusion on the bearing surface of the bolt head that serves to prevent it from turning.
The mustache of the bolt. A protrusion on the bearing surface of the head and shaft of the bolt, which serves to prevent it from turning.
Gimlet. The threaded, tapered end of a screw used to cut a thread in a wood or plastic product to form a joint.
GOST 27017-86 fully complies with ISO 1891-79 and should be used in conjunction with GOST 11708-82 “Thread. Terms and Definitions". GOST 27017-86 establishes terms and definitions for fasteners for general machine building applications. Standards establish only basic terms. Today, when new types of fasteners appear in Russia, the process of the formation of terminology is observed, strictly speaking, this is a constant process. The desire of market participants to avoid discrepancies in the names is quite natural.
The quality of assembly of furniture and the reliability of its operation are largely influenced by fasteners designed to connect individual elements to each other and used for mounting products. Of course, the type and design features of fasteners depend on the category of furniture and its operating conditions.
The modern industry offers a sufficient number of new fastening accessories that greatly facilitate the assembly of furniture and increase the durability of its use in the most adverse conditions. For example, kitchen designs made from cheap particle board are more likely to fail by delamination of the panel or peeling of the decorative coating than to fail due to poor quality or reliability of fasteners.
Today, in the industrial and independent manufacture of furniture products, quite a lot of types of fasteners are used, which differ in functionality, method of fixation, size and protective coating.
Categories of fasteners
If half a century ago, the main elements for assembling furniture components were wooden dowels, and the installation of various specimens at the place of operation was carried out using nails or screws, today the range of accessories for connecting individual parts and furniture elements has expanded significantly.
Modern fastening and connecting parts can be divided into several categories, including both highly specialized products and universal fittings:
The most common types of furniture fasteners
Consider the most common groups of connecting and fixing fittings for furniture, the features of its installation and operation.
Button head or ornamental head screws and bolts with a fixing mustache or square neck are the main examples used to tie individual panels of frame furniture. Thanks to the fixing mustache or square head, the bolt (screw) is fixed in the hole of the chipboard, which prevents it from turning. Due to this design feature, the assembler has the ability to tighten the nut without additional fixation of the screw.
Universal screws with countersunk or semi countersunk head have slots of various shapes (cross, with an internal hexagon, a straight slot, and others) and are designed for fastening individual assembly parts inside furniture structures. They are used for:
On a note!
When using universal screws, either screwdrivers with interchangeable bits or screwdriver sets with interchangeable tips are used.
Confirmates (Euroscrews) in modern furniture production are the most popular type of fastening and fixing devices. This type is used for fastening any parts made of chipboard or MDF panels.
Before screwing the euro screws, holes are pre-drilled in the parts using a special confirmation drill, the diameter of which depends on the diameter of the fixing element. To screw this type of fastener, it is used either with special bits or screwdrivers with seed nozzles. The type of bit or nozzle depends on the type of slot.
Eccentrics other fittings, bearing the somewhat exotic name of rastexes and minifixes, allows you to connect and pull panels located at right angles to each other. Despite the obvious advantages of this category of fasteners, their main disadvantages are:
- the need for additional milling of furniture panels, for the installation of individual fastener parts;
- relatively high cost.
- high accuracy of marking and the complexity of installing individual fasteners;
On a note!
To install individual minifix parts, you will need three different types of woodworking tools - one end mill and two drills of different diameters.
Furniture corners proved to be a reliable, easy-to-install element. Today they can be made either from metal or from special, high-strength plastic. In industrial production, the color of the plastic corner is matched to the color of the furniture.
Modern furniture dowels made of wood, plastic or metal. Their main advantages are low cost and ease of connecting furniture parts to each other. To increase the reliability of the connection, there is a corrugation on the surface of the dowels.
Special types of fasteners
Today, furniture, the individual parts of which are made of glass sheets or in the form of mirrors, is becoming increasingly popular. If ten years ago glass was mainly used as doors for furniture cabinets and showcases or doors for shelving and shelves, today you will not surprise anyone with a glass top for a coffee or dining table.
To interconnect glass parts and furniture elements made of other materials, special types of fittings are used, which are attached to glass surfaces with the help of special adhesives, by wrinkling clips with rubber gaskets or by drilling holes in the glass. When choosing this category of fittings, it is necessary to pay attention to the weight that it can withstand, which is especially stipulated in the instructions for its use.
The review will focus on the latest furniture fittings.
Modern fasteners
In the last decade, new building technologies have come to us from abroad, and along with them, modern building, facing and insulating materials. Unfortunately, much less is known about modern fasteners in our country.
General fasteners
Designed for fastening to any building structures made of concrete and brick - solid and hollow (from hollow brick to hollow blocks of aerated concrete). The fasteners include a dowel and a screw for wood or chipboard.
Fasteners for hollow materials
It is used for fastening light elements - lamps, shelves, skirting boards, switches, cornices, hangers, paintings, etc. to hollow (thin-walled) structures, such as drywall, gypsum fiber sheets (GVL), chipboard, sheet steel, hollow profiles , ceilings with voids, hollow doors, etc. Fasteners consist of a special dowel for hollow materials and a screw.
Dowels for insulation materials
Designed for mechanical fastening of hard and soft insulating materials in the form of a panel or sheet (stone wool, glass wool, polystyrene, polyurethane, foam plastic, fiberboard boards, mats made of coconut fibers, cork, etc.) on a plane made of concrete, lightweight concrete, natural stone, solid and hollow bricks, hollow blocks and aerated concrete. For installation of some models of such dowels, additional nails and screws are not required. Other models are supplied with a steel expansion nail. Leading manufacturers of fasteners use for this purpose only galvanized and passivated (with additional coating) steel nails with increased bending strength.
Dowels for aerated concrete
From the very name it is clear that they are designed specifically for fastening windows, doors, gratings, consoles, pipelines, suspended ceilings, wood and metal structures, cable routes, plumbing equipment, etc. to building structures made of aerated concrete. locking screw made of galvanized and passivated or stainless steel.
This is the most modern class of fastening systems. They are designed for mounting parts on structures made of heavy concrete, dense natural stone and other dense equal-strength materials in cases where an increased level of reliability and safety is required (including for fastening facade cladding and load-bearing structural elements - traverses, consoles, etc.). ). The principle of operation of chemical fastening systems is based on filling the prepared hole with a special two-component mixture, which, when solidified, “tightly” fixes the anchor or threaded rod in the hole (the end of the rod that comes out looks like an ordinary threaded stud). The mixture is in a glass cartridge, which is inserted into the hole. After that, a rod is screwed in, which crushes the glass, and the mixture fills the entire volume of the hole.
Injection Mounting Systems
They are a type of chemical fastening systems. The difference lies in the way the hole is filled - in this case by directly squeezing the mixture out of the cartridge, similar to the use of sealants. Such fasteners are used for the installation of gratings, fences and railings, pipelines, plumbing, etc. Depending on the material of the building structure - hollow or solid - the system is used, respectively, with or without an anchor sleeve.
It is used for fastening sinks, urinals, bidets, wall-hung toilets, water heaters to wall structures made of concrete, natural stone, solid brick, solid gypsum boards, hollow blocks, aerated concrete (there are special models designed for fastening to walls made of plasterboard, gypsum fiber boards, chipboard) . The structure of such fasteners includes a dowel, a galvanized and passivated steel stud, a nylon nut with a collar and a metal decorative cap. Toilet bowl fasteners are designed to fasten toilet bowls to a concrete floor. It consists of a dowel, a brass screw, a blocking sleeve and a decorative cap.
Fasteners for balcony structures
Designed for fastening balcony cladding made of wood, polymeric materials and metal, general cladding, small pieces of equipment, wire ties, building elements, etc. to structural elements of balconies. Simply put, such fasteners are designed for fastening to thin-walled metal elements from which a balcony fence is assembled (pipes, profiles, sheets, panels and plates a few millimeters thick). The fastening consists of a nylon spacing cartridge with a shoulder, a brass screw and a decorative cap.
Frame fasteners
Designed for fixing frames, wall and plaster joint profiles, wooden parts (including lathing for plaster), skirting boards, wall brackets, cable ducts, cable and pipe clamps, etc. Fasteners consist of a special frame dowel and expansion screw.
Designed for invisible fastening of wooden steps to concrete or metal profiles, solid brick, natural stone. Fasteners include: a nylon dowel with a shoulder for fastening to solid materials or a nylon expansion cartridge with a shoulder for fastening to thin-walled structural elements, a brass or steel galvanized and passivated screw, a core for precise marking of holes in the board. Such fasteners can be used not only for stairs, but also for invisible fastening of any other wooden elements.
Dowel clamp
Designed for fastening individual cables, flexible pipes or cable harnesses to building structures made of concrete, solid silicate and clinker bricks, natural stone, lightweight concrete and aerated concrete.
Clamp for cables and pipes
Designed for rational fastening of cables and pipelines to building structures. The clamps themselves are attached to the structures using dowels with a screw. These clips are available in various sizes, each equipped with a special element that allows you to fasten the clips together.
Fastener selection
When choosing fasteners, you need to remember that this is a very serious and responsible matter. After all, pieces of furniture, lighting fixtures, technical structures that are attached to walls and ceilings are, as a rule, located above human height (in any case, above the height of a child). At the same time, even not the heaviest of them (say, a picture or a sconce), breaking off the mount, can cause very serious injuries. What can we say about a hanging cabinet or a bookshelf that has fallen off the wall. Therefore, the main advice: if you want to feel calm and safe in your own home, use only fasteners from the world's leading manufacturers. Installation is a responsible matter, and the quality of your repair depends on how it is done, in order to choose the right fasteners (using the tables, you can easily select fasteners, depending on the material used) and learn about the latest in fastening systems, you can view Fischer Fastening Systems Catalog 2014.
Modern fastening systems are a guarantee of high-quality and reliable fastening
At the end of June 2017 in Germany, the Fischer Group, the world leader in the field, received the "Special Trust" ("Stein im Brett") award, becoming No. 1 in the field of building fasteners. The main criteria for obtaining high marks were product quality, price, ease of installation, and the desire to recommend products to others. The award was given based on a survey of builders and sales representatives. The questionnaire included 297 construction equipment suppliers in 26 product categories.
The ease of installation of Fischer products was especially noted. This is recognized as the most important aspect in the daily work of builders and one of the main reasons why craftsmen recommend fasteners from this German manufacturer to each other. In order to continuously improve products and simplify the installation process, Fischer specialists regularly organize meetings with installers and builders, as well as with representatives of trading companies. “After all, only those who work with our products on a daily basis help to find solutions to various construction problems at various sites and can truly judge the quality of products and services, as well as the level of the manufacturer,” comments Ralf Häfele, Managing Director of FischerGermany Sales GmbH.
The study was conducted during 3000 workshops by the ibau information center. The purpose of the survey was to determine the "most revered" brand and the best manufacturer in the construction industry. “This survey is the largest and most significant in the field of German trade,” said Sven Hohmann, Managing Director of ibau. The study was conducted with the support of the Heinze marketing agency and the Helden am Bau online platform.
Interstate standard GOST 27017-86 fully complies with ISO 1891-79 and should be used in conjunction with GOST 11708-82 “Thread. Terms and Definitions".
Bolt- a fastener with a metric external thread in the form of a rod or cylinder, with a head on the opposite end. The bolt head can be hexagonal, cylindrical - imbus bolt, or spherical - furniture bolt. Bolts form a connection using a nut or a prepared threaded hole in the product to be joined. Bolts come with full or partial threads.
Screw- one of the fasteners designed to form a connection and fixation. It is made in the form of a cylinder with an external thread and a structural element on the other, to transmit the translational movement of torque. Heads come with a spitz, knurled or just a slot in the end of the rod in the absence of a head.
Screw (Wood screw)- a popular fastener, in everyday life it is called a self-tapping screw. It has the form of a pointed, conical rod with an external special thread, and a head at the other end. The screw thread has a large root width compared to the width of a tooth with a triangular pointed profile. A thread is formed in the hole of the wooden or plastic product to be connected by screwing.
Hairpin (Stud)- a fastener in the form of a rod or a cylindrical rod with an external thread cut along the entire length of the product or only at the ends on both sides.
Pin- a special fastener having the form of a cylindrical or conical rod. It is intended for fixing various products in the assembly process.
Nut- a fastener with a metric threaded hole. For a constructive transmission of torque, nuts can be multi-sided, hexagonal, knurled on the side surfaces, with a slot, end and radial holes, etc. The design of the nut can be different: cap, extension nut (coupling), mustache, etc.
Washer- type of fastener, a product with a hole placed on the head of a bolt, screw or nut to increase the supporting surface of the fastener structure and prevent self-unscrewing.
Split pin- a special fastener is a form of a wire rod of a semicircular cross section, folded in half at the bend to form a head.
Rivet- a fastener of a smooth cylindrical shape in the form of a rod with a head, used to obtain a permanent connection, forming a head at the opposite end of the rod through plastic deformation.
Hardware- abbreviated phrase "metal products". The concept of Hardware, combines a very wide range of different goods obtained and made of metal. Conditionally divided by purpose: general purpose and industrial.
General purpose hardware- metal products used in everyday life: scissors and knives, agricultural items: pitchforks, shovels, rakes, various saws, hacksaws and much more.
Industrial hardware- metal wire, steel ropes, steel tape, nails, metal mesh, spring washers, split pins, crutches and rivets used in railway construction, railway rails, telegraph hooks.
fasteners- this is a type of product that allows you to fasten parts together. The more durable the material from which the various fasteners are made, the strength and durability of the product as a whole depends.
In general, such a concept as fasteners appeared long before the reckoning and our birth. For example, historians and archaeologists say that the first nail was not metal at all, but from fish bone, sometimes from plant thorns, or simply carved from hardwood. By the way, the original building fasteners were wooden and at the same time quite strong, as evidenced by the structures of Kizhi that have survived to this day and still amaze tourists with their fortress. At the same time, until the 15th century, inclusive, all threaded connections were made individually, manually. At the same time, the bolt and nut were quite expensive and one nut fit only one bolt. Bolts and nuts, as the most effective and time-tested fasteners in the form of a bolted joint, became widespread along with the development of electrical metalworking.
The main types of building fasteners and fasteners indispensable in the construction of buildings and repair work in the premises.
Construction fasteners- the direction of fasteners used in construction to connect building structures and various structures. This group includes such fasteners: self-tapping screws, bolts, screws, anchors, studs, nuts, clamps, couplers, nails, screws, dowels, screws, cotter pins, washers and similar products.
Metric fasteners- these are fasteners of a product that have a thread pitch of a certain size (thread pitch is a rule for determining a particular distance between any two points). This type of fastener includes bolts, nuts, screws, studs.
Stainless fasteners has a high degree of corrosion resistance and thus has an advantage over other types of fasteners. Corrosion resistance under adverse conditions for stainless fasteners is much higher, in addition, it perfectly resists oxidation in alkaline, acidic environments, and in chloride solutions.
Due to the long service life of hardened stainless steel fasteners, they are classified as high-strength fasteners. High strength fasteners one of the types of machine-building fasteners, so called because it can withstand more significant loads and has a strength class of 8.8, 10.9, 12.9, does not lose its strength characteristics at high temperatures.
Anchor- a fastener of the category of building fasteners, there are varieties: anchor bolt and anchor nut. The anchor is able to stay inside foundations or a solid wall, (strong, inelastic, non-fragile construction). Designed for fastening construction and other equipment as well as various designs. Anchors are usually used in all construction subjects, from dams, nuclear power plants, to a typical building, inclusive.
Classical dowel used for fastening any parts in a solid, non-fragile and durable wall or ceiling panel. The principle of fixing the dowel is a thrust during installation from a screw or screw, which causes a holding force of friction.
collar- another type of fastener. Clamps are mostly made for connecting any types of pipes made of metal and plastic. Plastic clamps are used for fixing less durable material than metal clamps, however, they provide greater pipe mobility.
Modern construction rigging makes it possible to choose fasteners for various types of construction work. Such a type of rigging as an eye nut and an eye bolt are used to organize the lifting and movement of goods during lifting and rigging operations. A steel rope or cable is used for lifting heavy objects in construction, these positions are an important part of the current hoisting mechanism, both for hand hoists and for cranes. The chain is also one of the types of rigging. Steel chains are used in various lifting mechanisms, from manual to cranes. Steel chains, like steel ropes, are used to lift and move loads for various purposes and structures.
Each fastener is made for specific purposes, so there are a great many types of fasteners, because fasteners are developed and used for a specific material and from specific parts. For example, using certain types of fasteners, you can connect metal to drywall, metal to metal, metal to gypsum fiber, and metal to wood.
Alternative types of connections have both advantages and disadvantages. For example, the so-called "liquid nails" - due to the ease of fastening, it is really easy to connect the parts together. However, what is glued together cannot last happily ever after. Glue - has a chance to peel off in one day, that's why it's glue! Fasteners or hardware has not been canceled!
