A dowel screw is fastener, intended for securing any objects and structures in solid solid materials. The operating principle is based on the friction that occurs when the dowel is pushed apart by a screw, screw, nail, etc. installed in it. Let's consider the main representatives of this attribute of the construction process.

Mounting dowel - from what and for what?

It is unknown who invented the dowel and when, but the first patent for the invention was received by John Joseph Rawlings on January 14, 1913 in London. Today, not a single renovation is complete without the need to nail something to the ceiling or walls. And if in houses with wooden walls The problem is easily solved with a hammer and nails, but attaching anything to concrete walls without a dowel will not work. There are a huge number of such devices, they differ in material and retention principle. There is also plenty to choose from for the length and weight of the dowel-nail.

Until recently, a dowel was most often cut from pieces of wood and inserted into a drilled hole in the wall. Now hardly anyone uses this archaic method - the industry produces a lot of dowels, for any materials and for all occasions. They are made from plastics (polyethylene, polypropylene) and metal. The most commonly used standard nylon dowel is that it allows you to solve almost all household problems. Such devices in combination with self-tapping screws can be used in any wall material.

The mounting dowel is made from both propylene and nylon. Polypropylene can only be used indoors, because... This material does not serve well at low temperatures - it cracks. Products made from nylon work well in any conditions. The spacer device can be used when working with solid materials (concrete, brick) and with hollow blocks. It is fixed with the help of special antennae, which hold it firmly and do not allow it to rotate in the hole.. Some types of fasteners are a dowel for a mounting gun, the principle of its fastening and appearance They are somewhat different from standard ones with manual installation, but the efficiency does not suffer from this, and in some cases this will even be the most reliable option.

Dowel screw - features of fastening to various surfaces

The construction expansion dowel with a locking collar is made of nylon. These varieties are used mainly for the installation of building structures. The locking collars prevent the dowel from falling into the hole; this device is used primarily for outdoor work. The product without a collar is made of high-quality polyamide. This dowel has a through hole, longitudinal ribs and a non-expandable upper part. Thanks to this design, screwing in the self-tapping screw is simplified, the expansion of the dowel is increased, and the stationary upper part protects the plaster layer from cracking and falling off. This option is weather resistant and has increased durability.

The dowel is made from both plastic and metal. It is intended for fastening any elements to slabs of plasterboard, gypsum fiber or porous concrete. For metal products, you do not need to pre-drill a hole - their tip looks like a feather drill, and the spacer part looks like a large thread. This dowel is screwed into the body of drywall or porous concrete using a screwdriver.

The mounting dowel-nail is designed for quick fastening of windows, baseboards, sheathing, etc. to any surface. It is sold complete with a nail that is knurled for retention. The knurling is made in the form of a thread with a reverse cone. Such a nail-screw can be screwed in with a screwdriver, or it can be driven in with a hammer. The reverse knurling cone securely fastens the part into the wall. It is rational to use such a device in mass production, because the ability to drive a screw speeds up the work significantly. The adjusting dowel is intended for installation of wooden structures with interior decoration premises. The split dowel allows you to level out the unevenness of load-bearing walls without the use of wedges and blocks.

A universal dowel in a thick wall works as a simple spacer, and in a thin wall, after passing through the wall and entering the cavity, the product is wound around a screw and tied into a knot, resulting in a reliable fastening.

To fasten home appliances (air conditioner, range hood, etc.), you can safely use the fasteners supplied in the kit. They are always calculated with the necessary safety margin. When choosing dowels yourself, you need to be guided by the material of the walls and the weight of the element being fixed. For fastening, for example, Swedish wall, the mounting depth must be at least 80 mm, and the wall material is concrete or brick; it is strictly forbidden to attach heavy objects to plasterboard walls. For fixing chandeliers, suspended ceilings etc. you need to choose special dowels with deep transverse notches and spacer ribs. In specialized stores, in case of difficulty, sales consultants can provide qualified advice.

Construction dowel – special types of fasteners

The butterfly dowel is used when working with thin walls. The cut part goes right through the wall and opens up when the screw is tightened on the reverse side. To prevent the product from turning, a cuff is provided. The fastening is immovable and durable. Frame dowels are used for fastening door and window frames. They are produced in two types - for solid solid walls and for hollow soft walls. The length of the dowel must be chosen so that it passes through several jumpers, then the spacer part will ensure reliable fastening. Varieties with a length of 60-360 mm are available.

A separate group consists of dowels, which are called facade connectors. They are designed for attachment to any surface. This is also a spacer product that has an enlarged collar with a plate so that the soft material ( mineral wool, fiber boards) did not slip off the fastening. Facade dowels are made from reinforced polyamide with increased impact strength.

Anchor dowels consist of two parts: a sleeve with slots (collets) and a rod. The rod is screwed into the sleeve, pushing the collets apart and rigidly securing the structure in a pre-drilled hole. They can be used for hard, durable materials. Collets that are loose and porous under mechanical action can be destroyed, and the required joint rigidity will not be achieved. The protruding part of the rod can have both an external and internal thread. Accordingly, fastening is carried out using a nut or screw (bolt). The thread is most often metric.

Chemical types of construction dowels

Chemical anchors are divided into two groups: injection and ampoule. Injection anchors are more common. The role of the dowel is performed by the adhesive composition, which is squeezed out of the cartridges into the drilled hole. Cartridges are available in capacities up to 800 ml. The work is carried out using construction syringes, similar to those used to fill sealants. Fasteners can be very different - screws, screws, nails, anchors. The cost of such dowels is commensurate with the cost of conventional ones, but they significantly benefit in production speed installation work. In addition, the composition fills all voids, which is convenient when working with porous materials, because this increases the strength of the connection.

An ampoule dowel is a hermetically sealed cylinder with an adhesive composition. The ampoule is placed in the prepared hole, then a metal anchor is screwed or driven in there with force. The ampoule collapses, the glue fills the space and hardens upon contact with air. Synthetic resin is used as an adhesive. The resin can consist of two components, in which case the ampoule must be double. With the help of such a dowel, installation is very convenient and quick. The fastening is strong and quite rigid. The disadvantage is the high cost; it makes sense to use it only in very important work.

Are anchors suitable for wood? How to securely attach a chandelier, hanging bed or other massive thing to wooden beam? What other means can be used when merging wooden structures? Let's find out!

Types of anchors

The word “anchor” is of Germanic origin, its main meaning is “anchor”. Anchor fasteners are used when installing various products on a base made of wood or concrete.

There are several types of “anchors”:

• spacer;
• persistent;
• adhesive;
• Bolt Molly.

The expansion anchor is held in the workpiece by frictional force. To maximize it, the rod installed in the hole is expanded plastic dowel or a wedge stop with a thread inside.

The fixation of the thrust bolt is ensured by the ribbed or expanding part of it embedded in the base. This is exactly how the fastenings used when installing heavy production plants on a concrete foundation are designed.

Adhesive “anchors,” as the name implies, adhere to the surface due to the sticky composition entering the void between the walls of the hole and the ribbed rod. Most often, the role of an adhesive mixture is performed by a polymer resin with a hardener.

The Molly bolt is used when hanging products on low-strength partitions made of gypsum fiber board, chipboard, gypsum board and hollow brick. In the process of tightening, Molly pushes the outer shell apart. As a result, a stop appears that is in extensive contact with the base.

Note: craftsmen often call adhesive anchors “chemical”.

Now let's figure out what type of anchor bolts are suitable for in various ways fastening to wooden structures:

• The Molly Bolt can only be used on surfaces that have voids inside large area. That is, this method is only suitable for hanging relatively light objects on partitions made of boards, chipboard and lining;
• thrust anchors are used only in the process of creating a massive foundation. In the case of wood, this is the growth stage of the tree trunk, so such fastenings will not suit us;
• glue “anchors” can be used when working with wood, but this is not always advisable due to the high price of this product.

Important: large changes in humidity can lead to a loss of adhesion between the body of the chemical anchor made of hardened resin and the walls of the hole, which will cause the fastening to become unusable.

Based on the above facts, we can conclude that the anchor fasteners for wood must be spacer. However, another important factor should be taken into account here: depending on where the force is directed, the strength of the wood may vary:

1. If the force vector runs parallel to the fibers, the material is more tensile;
2. If the force vector is perpendicular to the fibers, the destructive force will be several times less.

Speaking in simple language, wood is more likely to split if wedged between the grain. At the same time, typical expansion fasteners produce a radial expansion force, which can pose a danger to the wooden base.

To reduce the pushing force, craftsmen resort to a simple maneuver:

• The wood itself is used as a dowel (propping element);
• The hole for the rod is made only slightly smaller than the diameter of the ridges of its thread.

The design that matches this description is probably familiar to you - it’s... an ordinary screw!

Wood fasteners

Fasteners suitable for connecting wooden structures have several features:

Manufacturing options

The most common types of wood anchors are:

• hex head bolt. It is used for attaching various brackets, plates and other flat and large structures with lugs to wooden bases;
• a stud with a nut, which is screwed in with a wrench (open-end or adjustable);
• a hook that acts as a strong suspension and is suitable for mounting chandeliers, hanging shelves, lanterns, and so on;
• the ring performs the same functions as the hook. Home it distinctive feature- the ring prevents the suspended product from jumping off it when moving in space (for example, the ring can be used when creating a children's swing). To attach a suspended structure to it, threaded or spring carabiners are used.

Installation

How to screw a wood anchor with your own hands so that the fastening is as reliable as possible and the base does not split?

The procedure in this case is not at all different from the technique of screwing in a large diameter screw:

• drill a hole at the mounting point. Its diameter must correspond to the diameter of the fastener along the thread recesses. So, a channel for a 10 mm rod must be made with an 8 mm drill;
• Apply some liquid or solid soap for lubrication;
• screw the rod in to its full depth.

Important! The depth of the hole should correspond to the length of the rod. If the depth is less, then the bursting force on the wood will increase sharply, which can lead to the appearance of cracks (if not immediately, then as the structure is used).

Other types of fasteners

In addition to the "anchors", wooden structures can be connected using conventional bolts, studs, perforated plates and angles.

Bolts

With their help, you can fasten two or more overlapping parts (however, the joined products must be quite thin). This method fastenings are convenient to use when building up rafters: two boards are laid overlapping by three of their widths and, through pre-drilled holes, are tightened with two or three fasteners with nuts and wide washers.

Hairpins

The stud is similar, but has the advantage of having nuts on both sides. This fastener design allows you to tighten the fastener without turning the rod. This is convenient if the pin is jammed by the connected parts. In addition, if the rod is long, the force required to rotate it can be very large.

Corners and overlays

Perforated steel plates and angles should not be considered as competitors to anchors.

These types of fasteners complement each other:

using corners, you can join the floor joist boards with beams or crowns without cutting (butt-joint);
plates allow you to connect boards in a similar way when splicing rafters or joists.

Important! To make such a connection reliable, choose a plate with a length of at least five times the width of the board. In addition, to fasten boards with overlays, you should use not “anchors” or self-tapping screws, but bolts with wide washers.

Conclusion

Understanding how to interact with wood various types anchors will help you choose the optimal solution to your tasks.

Video: how to install anchors

To use various wood compounds in the field of construction, you cannot do without just tools, but also without the appropriate experience. That is why inexperienced craftsmen do not always make such connections accurately. One of best options— professionals use various types of fasteners for the array, which are made of metal.

Many surviving architectural monuments made of wood were built without nails, using only an ax. This fact causes true pleasure to this day. However, centuries later, the fasteners made of metal, used to build solid wood buildings, have changed radically, and it is for this reason that today it makes no sense to repeat the experience of our ancestors.

It is preferable to build quickly and without complications. Let's talk in more detail about the fasteners offered by manufacturers, taking as an example details that make it possible to simplify as much as possible the connection of beams with floor joists or solid wall surfaces.

Perforated fasteners

When beams, as well as floor surface logs, are hidden in the interior space, they can be connected using beam shoes. This fastener for wood structures is suitable for fastening solid wood not just to wood, but also to concrete and brickwork. It is created from durable steel.

Manufacturers advise attaching such fasteners to the parts being connected with special screws, and in case of excessive load, or fixing to a stone material, use the holes for the necessary bolts. In addition to anchor shoes, today you can purchase special clamps and much more.

Tenon and groove

This galvanized wood fastener consists of a tongue and groove section that fit together to provide better transfer of horizontal as well as vertical forces.

The connection can be visible or hidden; for these purposes, the steel parts are recessed into special grooves in advance.

Three-dimensional slats

The modern Italian company produces fastening elements that are placed perpendicularly and vertically at an angle, using T-shaped slats created by extrusion from a high-strength steel alloy. They are produced in several modifications designed for different levels of loads.

The fastening system must be selected according to the size range of sections of the combined beams and the dynamic as well as static loads acting on them.

During installation, the slatted base is attached to the beam using self-tapping screws. Then a groove of the same size as the slatted shelf is created on the end part, attached to the base of the joist beam. If there is no perforation, the shelf is equipped with a log and the connection is secured using self-tapping screws.

Hidden details Hedgehog

These connectors are steel washers, the base of which is equipped with holes drilled under the slope. These holes are for self-tapping screws. In the center of the washer there is a threaded hole into which a pin is inserted. Its free end is threaded into a special hole and secured on the back side of the beam with a piece with an enclosed washer.

The created connection functions perfectly not only in pull-out, but also in shear. If there is excessive load in the area of ​​the end part of the joist, it is possible to install several elements at the same time.

Fasteners with complex threads

Unusual self-tapping screws that make it possible to save time, cash, since this option does not require metal parts. Self-tapping screws are equipped with threads, which help create a high degree of resistance when pulled out, and are also tightly screwed into an array, which completely changes their traditional functioning.

In this case, the work of the screws occurs exclusively by pulling out, which gives them the opportunity to absorb most of the forces that fall on the connection. So, you can fasten elements at an angle, combine parts, minimizing their deflection, as in the photo of wood fasteners below.

Special purpose self-tapping screws

Using similar elements, fairly massive wooden products are attached. The cap has milled ribs and is easily recessed into the product, while the tip is created like a drill. In the middle of the screw, the cutter makes a larger hole, helping to tighten the element as tightly as possible.

An adjustable self-tapping screw will be useful for fastening door frames, window openings, and solid wood sheathing to wood and metal. The self-tapping screw is screwed directly into the box, as well as the wall surface located behind it, or the power part.

The self-tapping screw acts as a weather vane for high-quality fastening of solid wood cladding to a base made of steel. It has a tip in the form of a drill and wings placed above it to expand the hole in the tree.

When drilling metal products, the wings break. As a result, having made a thread in a metal part, the self-tapping screw fits tightly to it, while the solid element is attracted by its head to the metal.

Photos of wooden fasteners