Construction dowel - what is it? Nagels for fastening timber - an indispensable component in the construction of wooden structures Nagels in which cases are used

Any structure needs fasteners. Dowels are used for fixing window and door frames to a concrete base, for many other concrete and wood work. What is a concrete screw dowel, how is it used?

Foma and varieties of nagel

Nagel - what is it? Translated from German simply "nail". Initially, this was the name of wooden nails used to fasten beams and logs in the construction of houses. Wooden nails are sometimes used now, but they have serious disadvantages: insufficient strength, susceptibility to decay.

In addition, wooden fasteners are only suitable for connecting wooden parts. The iron dowel for concrete is universal: they can fasten metal, wood, plastic to concrete, brick, stone, foam blocks, etc.

Today, metal turboscrews are widely used in construction. This is a galvanized steel self-tapping screw with unevenly applied threads (uneven threads resist pushing out better when the structure shrinks). From the inside, the cap has a conical bevel and there are notches for countersinking. From above, the hat is most often flat, the slot is a cross or an asterisk.

Metal screws

Other forms:

• conical head with cross slot;
• hexagonal hollow with internal thread and cross slot;
• head with a rectangular or rounded profile;
• self-tapping screw for concrete in the form of a stud with a threaded drive for a nut, etc.

The standard diameter of the dowel is 7.5 millimeters. The most popular screws are from 5.2 to 20.2 cm long. They can be used with and without dowels.

Dowel nail

Manufacturing nuances

In addition to the shape, concrete screws have other differences. According to the type of protective anti-corrosion coating, they cover:

• galvanized. This type is suitable for most construction operations: interior work, facade work, basements, roofs, etc.;
• coppered or blackened. Both types have a reduced resistance to moisture, they are unsuitable for use on facades and in basements. Apply to internal works in dry rooms.

An example of how the size of the dowel for a 6 mm drill can vary:

• outer section - 7.35-7.65 mm;
• threaded diameter - 6.3-6.7;
• thread pitch - 2.55-2.75;
• internal section without thread - 5.15-5.45;
• head height - 2.8-3.2;
• cap diameter - 10.82-11.82;
• slot depth Torx 30 - 2.3-2.7;
• rod length - 50-184.

Forms of dowels

The choice of hardware and the calculation of the required quantity

Application dowel screws:

• fixing PVC windows;
• wooden windows;
• door frames;
• metal profiles for drywall;
• hanging shelves, mirrors, paintings;
• fastening to the facade wall of a batten for a ventilated facade, etc.

The dowel for concrete is selected based on the expected load on it. For a load of 100 kg, a suitable screw length is 15 cm. For 10 kg, 7 cm is enough.

Usually the pitch between the screws is from 7 to 10 cm. When installing PVC windows, the maximum pitch is 6 cm. The distance from the edge / corner depends on the type of work. For example, windows are fixed 5-6 cm from the edge of the frame or further.

Mounting Features

How to use pins:

1. Attach the structure to be fixed to the surface, level it and mark the fixing points on the surface through the mounting holes.
2. Drill holes. The diameter of the drill must be approximately 15% smaller than the section of the screw in order for it to be firmly fixed.
3. Clean dust from drilled holes.
4. Attach the structure again and screw the dowel screw. The size and shape of the screwdriver / screwdriver bit must match the size and shape of the slot.

Fastening metal profile sheets

Conclusion

The dowel for concrete is a reliable, strong, durable fastening. It is inexpensive and easy to use. The only thing that is required is accuracy. When screwing, do not apply excessive force so as not to damage the hardware. Too fast rotation must also be avoided: the head can overheat and break.

The density of concrete in many respects is very high, which makes it an ideal building material for the construction of walls and ceilings. However, it is very difficult to mount fasteners for shelves, chandeliers and other “hinged” interior details in it. In this article, we will look for a solution to this problem, and the pin will help in this.

What is it and where is it used

It is a conventional self-tapping screw with a reinforced stem and a hex head that can be screwed into concrete.

In addition to small items, they can be used to strengthen:

• door frames ;
• frames;
• fences;
• pipelines;
• heating radiators.

Below we will deal in more detail with the varieties of such fasteners, as well as with how to use the dowel on concrete correctly.

Kinds

Hardware products used for installation in concrete surfaces are usually classified according to the following criteria:

The shape of the head directly affects the installation of the self-tapping screw. For example, screws in the form of hooks and studs can only be installed in a hole that is pre-drilled and with a dowel. Others without drilling or with it.

For example, screws with a hexagonal or countersunk head are screwed in without reaming the mounting hole. However, not every concrete is suitable for such installation.

Tip: cellular concrete is the best, and reinforced concrete for this method mounting is not suitable.

The price of self-tapping screws depends on the scope of their application, the shape and pitch of the thread, and the length of the hardware also affects it. With a herringbone, products will cost less than dowels and universal ones, and a 12 mm long screw will cost less than 200 mm, since less material and working time will be spent on it

Choosing and installing screws

Typically, concrete screws are selected according to the amount of load that they will have to withstand due to the weight of the interior part. For example, to support 100 kg, you need a self-tapping screw with a length of 160 mm and Ø10 mm, but a shelf weighing 5 kg will hold a self-tapping screw up to 25 mm long and Ø3 mm.

After determining the type and size of the product, you can proceed to the installation procedure. In this case, pins and universal screws can be screwed into the wall (floor or ceiling) immediately, without pre-drilling the base, at the same time, you will have to tinker with a self-tapping screw with a herringbone thread.

Tip: the herringbone screw should be installed in the mounting hole, the diameter and length of which must exceed its dimensions by 5 mm.

This is due to the fact that after drilling, it is required to install a dowel in it (preferably in tension). He may be from polymer materials or wood, its main duty is to accept and hold fasteners. You can screw the self-tapping screw into the dowel with your own hands with an ordinary screwdriver.

Tip: After drilling a hole, remove dust from it.

It is important to use the self-tapping screw correctly, otherwise it can simply be broken off. It is necessary to tighten a screw with a countersunk head with a certain force, making sure that during the process it is not broken by simply pulling it. You can also break off the head due to high temperature body heating

So what is a nagel? Simply put, a dowel is a pin (fastener) made of wood or metal. Nagels are round, square or rectangular. The main task of the dowel is to prevent the displacement of building structures from each other, in particular beams (logs) in a log house. For the manufacture of wooden dowels, as a rule, denser wood (for example, birch) is used without knots and external flaws with preferably less moisture by 4-5%. The surface of the dowel must be smooth so that it allows the crowns of the frame to sit down without hindrance.

The very technology of assembling houses without a single nail using wooden dowels has been known since ancient times. Many of these buildings are kept by the historical complex of Kizhi, demonstrating the professionalism of ancient architects. In Rus', nagels were called kukses, and performed exactly the same role. The name nagel (nagel) came to us in the 17th century from Germany along with wooden shipbuilding. Wooden pins helped to tightly dock ship elements. When swollen from sea water, the dowels tightly filled the mounting holes, preventing leaks. Attempts to use metal dowels were not successful, because. sea ​​salt had a detrimental effect on the metal, corroding it in the first years of the ship's operation. So it was the wooden dowel that firmly got used to our everyday life, displacing the metal counterpart. In other matters, in vain, because the strength characteristics of iron are many times higher.

Installation of dowels round section

As it was written earlier, the main task of the dowel is to prevent the transverse displacement of the crowns relative to each other. The holes for the dowel are made strictly vertically in order to exclude the hanging of the crowns of the log house and not to prevent dense shrinkage. The diameter of the hole and the dowel is selected so that the dowel does not hang out and does not go in tightly. Driven into a tight dowel, it can prevent the shrinkage of the log house. The length of the dowel is calculated from the thickness of the two crowns, moreover, it should be a couple of centimeters less than the length of the hole. The first dowel is installed at a distance of 50 cm from the corner of the log house. All subsequent pins are mounted in increments of 1.5-2 meters. On all subsequent rows, the dowels are mounted in a run-up, excluding coincidences with the previous crowns.

The assembly of a log house on a square dowel is a rather rare case, due to the difficult selection of a comfortable combination of dowel thickness and hole diameter. The very same technology for mounting square pins is completely identical to the technology for mounting round pins.

Installation of flat (rectangular section) dowels

A distinctive feature of this technology is the more frequent arrangement of pins with a step of 50-60 cm in a run-up, alternating holes along the street and inner sides. The holes are made with a chainsaw and sawn to the full width of the chain bar. Wooden strips from a board or plywood are used as dowels. This technology is more budgetary and easier to install, since the cost of a set of dowels is much lower than the cost of factory-made round birch dowels.

Although “nagel” means “nail” in German, this is a slightly different type of fastener. Unlike screws, and screws in joints, it weakly resists external pressure, working more on shear and preventing bending of structures. It is usually used in the construction of wooden structures from logs, timber or boards.

What is

Dowels differ from most types of fasteners: they have no hats, no threads. Outwardly, these are straight wooden or metal pins 12–15 cm long and 10–30 mm in diameter. They are designed to work with wood, although there are dowels for concrete structures. The rods placed in the drilled holes prevent horizontal shifts of the fragments.

Wood tends to change in volume with fluctuations in temperature or humidity.. This is especially true for fresh materials. Depending on the structure, timber or logs can grow and shrink in size. As soon as the wood fragments begin to diverge, the surface of their contact with the dowels increases: the pins slightly bend under pressure, and the resistance to further movements increases. When the tree dries out, the pin stops experiencing high pressure and returns to its original position.

In order for the fasteners not to be destroyed during operation, it is necessary to correctly select the dowels, combining them in diameter with the holes in the wood. As a result, the walls remain smooth, deformation does not occur. Nail joints are more flexible than those provided by nails.. Fasteners prevent loosening and displacement of buildings.

Kinds

Since pins are used primarily for working with wood, they are often made from wood. Metal rods are also used. One or more types of fasteners from various materials are allowed.

Wooden dowels

Wooden pins or dowels are whips with a smooth cylindrical surface. The diameter of their section is from 10 to 35 mm. Length can be any: up to 1.5 m and more. When hammering into logs, segments of 10-15 cm are usually used. Fasteners from thin edged bars of square or rectangular section are less commonly used. The best raw materials for the production of dowels are hardwoods: or . Due to the relative high cost of these materials, or is more often used. Coniferous species are not suitable for these purposes because of their suppleness. Pins are turned only from dry material with a moisture content not higher than 12%. Used for both soft and hard woods.

Advantages of wooden dowels:

Wooden dowels are suitable for building boats, rafts, outbuildings, bathhouses, one-story houses from a log house, street furniture and other wood structures.

Disadvantages of wooden pins:

• low biostability;
• susceptibility to destruction;
• inability to withstand high pressure.

This type of fastener does not so much tighten structural fragments as it serves as a mortgage element, providing stability relative to each other. Working with wooden pins takes a lot of time, requires certain skills, and is quite difficult to perform.

Rounded dowels create a better grip on the surface, it is recommended to use it during construction bearing walls. Square fasteners are less durable, as they rest against the material only at the corners. It is used in the assembly of light parts or walls that do not experience massive loads.

Metal dowels

To provide a more rigid connection that can withstand high loads, a material stronger than wooden pins is required. When building walls of large structures, metal rods are used to fasten logs. The production of a similar dowel made of steel is almost impossible due to the high cost - dowel fasteners with a diameter of 25–30 mm for building a house would cost several hundred thousand rubles. Iron bars of this volume serve as powerful cold bridges when the temperature drops.

Greater strength than that of beech or birch dowel allows the use of metal rods when working not only with wood, but also with concrete structures.

Metal pins have more options in size and configuration, depending on the purpose:

• rods of circular cross section, hollow inside, resemble wooden dowels in shape, but have a smaller diameter;
• lamellar are designed for fastening several logs at once;
• bars of hexagonal or star-shaped section - fasteners for special purposes, rarely used;
• spring-loaded capercaillie: a type of galvanized self-tapping screws with a diameter of 10 mm, a length of 20 to 28 cm, the design of the fasteners provides for the use of springs clamped with washers, which allows the elements to withstand a load at the joints of more than 150 kg per 1 cm²;
• U-shaped hardened brackets and studs are used to tighten and fix logs from the end sides;
• dowels for working on concrete have the form of screws with variable threads, 7.5 mm in diameter, 70 to 200 mm long. They are screwed into the canvas with impact screwdrivers, pre-drilling of the material when working with them is not required.

Often, during construction, conventional pieces of reinforcement or pipes with a diameter of 10–12 mm are used as dowels.

Metal fasteners are stronger and more durable, stable, prevent wood from warping, do not fall out of drilled holes. The variety of forms of produced pins allows you to choose them for any type of screed. The lack of metal products is too rigid fastening. Because of this, for some time, the bars and logs can hang, gaps appear between them. Iron corrugated pins often split and spoil the surface of the tree, the difference in thermal conductivity leads to the accumulation of condensate.

Manufacturing

Industrial wooden dowel is produced from dry material of the highest or first grade, which does not contain frizz or knots. The structure of the finished fastener must be completely homogeneous. The parameters of industrial pins are regulated conditionally.

Common sizes:

• diameter 20, 25, 30 mm;
• length 120, 150 mm.

According to GOST, in the course of work, the diameter of the dowels should be ⅙ of the diameter of the log. Standard length pins are used to connect two logs, longer dowels are required to fasten several.

At the end of the manufacture, the dowels are treated with antiseptics.

If you have suitable wood, dowels can be machined on your own at home on a woodworking machine. Fasteners made in this way can have any parameters. It is recommended to make a long one, and later cut as needed. It is better to use a well-dried non-hygroscopic material.

Square dowels are made simply: the board is sawn along the fibers into long bars 20-30 mm in diameter, the edges of the segments are polished.

To get rounded pins, square bars are slightly larger required size fixed in lathe and grind with a cutter. In the process, the specified diameter is verified several times with a caliper, otherwise there is a risk of excessively thinning the material. Sharpened bars are cut and chamfered at the ends of the pins.

Mounting Features

It must be remembered that the dowels must necessarily be stronger than the material being joined. For example, larch pins are suitable for fastening pine logs, and birch wood must be fastened with no less heavy material: birch or oak. Logs and fasteners must be of the same degree of dryness, otherwise the mechanism for changing pressure and bending will be broken, the fastener will crack.

It is problematic to build a bathhouse or a log cabin for a house alone. To work with pins, you need to attract several workers.

Basic requirements to be observed during installation:

1. Holes in the central parts of the crowns are drilled strictly vertically - along the axis of the walls. The upper log is usually stitched through, the underlying one is ½ of its thickness. In cases where long dowel joints are used, 3 logs are drilled at once. The diameter of the holes should be such that the pins do not enter freely, but do not get stuck, they penetrate with little resistance.
2. For the first hole, they retreat from the corners of the building by approximately 40–50 cm, further holes are made every 1.5–2 meters. At the next level, they should be staggered.
3. In depth, the holes should exceed the length of the pins by 2–3 cm. This feature will protect the bars from hanging during seasonal swelling, and the dowels from deformation and destruction.
4. When hammering fasteners, it is advisable to use not a hammer, but a wooden mallet, carefully driving the pins with it.

The biggest difficulty in assembling wood structures is the correct direction or size of the holes produced. For inexperienced builders, they often turn out to be curved or not corresponding to the diameter of the dowels. Making the right connections in such cases can be problematic.

Concrete has a very high density, which meets the requirements for materials for the construction of walls and ceilings. It can be problematic to hang a shelf or other heavy structure on such a wall. However, there are special screws for concrete walls and partitions. They are suitable for different types designs and easy to use.

What is concrete dowel

Such screws are most often used for fastening heavy structures - frames, door jambs, cabinets, shelves, fences, radiators and other communications. The screw is firmly held by uneven two-start threads and notches along the entire length. This form ensures a secure fixation even in a concrete wall. On the head of the screw there are notches for countersinking.

The dowel for concrete looks like an elongated self-tapping screw with a thread in the center. On one side there is a head with a hexagonal groove, on the other side there is a sharp end. For their manufacture, carbon steel is used with a protective galvanized or anodized coating, which provides protection against corrosion and other influences. For screwing in, TORX T30 bits are used.

Fasteners can be reused, which is a big advantage for temporary structures. They are chosen for low price, resistance to moisture and stress and secure fixation of objects regardless of the material.

Benefits of using

The main advantage, compared with other concrete screws, is that it is used without a dowel. Before screwing something to a concrete wall, beam or partition, it is necessary to drill a hole with a diameter of 6 mm, then a dowel is screwed into it. The density of concrete does not matter. The screw can be used for dense or cellular concrete. In the walls of some types of cellular - you can screw self-tapping screws without pre-drilling.

Varieties of dowels for concrete

Head shape

• Hidden. A flat head that allows the screw to be driven deep into the structure without leaving a bulge on the surface. There are cross slots on the head. There are notches for countersinking.
• Rectangular. They are hook-shaped. May be round.
• Hexagonal. The thread is inside with a cross slot. For these types, open-end and box wrenches are used.
• Hairpin. There is a nut threaded drive.

The type of head affects the way the dowel is screwed into the concrete wall. A screw with a hook or a stud is mounted only with a pre-drilled hole. Other types can be screwed directly into the wall.

Coating type

• blackened. Self-tapping screws in black with an oxidized finish. They are used only for rooms with normal humidity. It is not used on the street or in basements.
• Copper-plated. Yellow color. Sensitive to various influences. Used for indoor work only.
• Galvanized. Silver color. Can be used inside and outside. Do not collapse or deform.

Nagel is used where other fastening is impossible: the base is too fragile, or installation causes certain difficulties.

The main sizes of screws that can be bought in stores

The dowel diameter always remains the same - 75 mm. The length of the working part is different - from 52 to 202 mm in increments of 20 mm, except for the 30 mm gap between 150 and 180 mm. Pins are sold in boxes of 20, 100 and 200 pieces. On some construction sites you can order from 1000 pieces. Between screws with different coating there is no price difference. The cost depends only on the length of the working part.

Drill for dowel on concrete: is it necessary

Before screwing the fastener into the concrete wall, a hole must be drilled. To do this, use a drill with a diameter of 6 mm. The width and length of the hole should be 15-20% less than the dowel itself. If an electric drill is used in the drilling mode, then a universal or special drill for concrete is suitable.

Using impact drill or a perforator, a drill is used that has grooves located on a cylindrical surface. For expanded clay concrete, foam or aerated concrete, it is not necessary to drill a preliminary hole. This is done in order to create complete contact between the screw and the concrete.

How to screw a dowel into concrete

Is it possible to mount heavy structures

Concrete dowel is used when working with structures made of different materials. It is used for metal, plastic or wooden products. Also, with its help, aluminum and plastic windows To concrete walls and beams. The notches made on the working surface of the self-tapping screw exclude arbitrary twisting.

They fasten with dowels aluminum profiles, door frames, roofs, stairs, canopies, fences, fire doors. When choosing the length of the working part, it should be borne in mind that a screw with a size of 7.5x72 mm can withstand a structure of 10 kilograms. To fix a structure weighing more than 100 kilograms, it is necessary to use a dowel of at least 152 mm. The bearing capacity of the self-tapping screw depends on the length of the working part. The material from which it is made allows it to be used in apartment renovation, construction and industry.

For concrete, the dowel is the most reliable fastening. Its low price and ease of use will be an excellent assistant in construction and repair. Minimum tools for installation and Various types screws will simplify repairs and make the fastening reliable and strong.