Dowel for a bar and not only: features of fasteners and selection rules

It is noteworthy that, despite the German name (“nagel” in translation into Russian means simply “big nail”), this type of fastening was widely spread in Russia. However, in Europe, nails were also used and are used, because wooden housing construction is popular in Western countries..

Despite the name, the nail looks a little like a nail. It is rather a pin, without a tip and a cap, smooth, even, very simple, but at the same time reliable and ideal for wooden houses type of fastening of individual beams and logs.

Nagels, edging, can be not only wooden, but also metal, as well as plastic. The latter type is rare, as it is rather unreliable. Metal pins in the form of an ordinary rod, strings or pipes are most often used in the form of reinforcement, fasteners for concrete structures, but in wooden housing construction they are used with caution. There are several reasons for this:

• The metal is characterized by high thermal conductivity. If a metal dowel is used to connect wooden parts, a cold bridge is guaranteed to appear;
• Due to the difference in the thermal conductivity of wood and metal, condensation will appear at the place of such a connection, and it will cause dampness in the wall;
• The metal pin can damage the wood;
• The metal is too strong, holds the wood rigidly, and we all remember that wooden houses shrink significantly.

Now such pins are allocated in a special position – screws for concrete, and wooden pins are used in the construction of houses from logs and beams, which we will continue to talk about.

Why did wooden pins become so popular? Because the technology was tested many centuries ago on wooden boats. The fastening made of wood under the influence of sea water did not rust; on the contrary, it expanded and sealed the hole, there were no leaks. After such a check on the expanses of water, wooden dowels deservedly became widespread in construction and on land.

We wrote about the process of installing a wooden dowel. Recall that small fasteners of this kind are called dowels and are used during the assembly of furniture..

The most common wood pins are round, but square ones are also used. It is believed that such pins have a smaller area of ​​contact with the area of ​​the hole, and this reduces the risk of rigidly fixing the log. There are pins in the form of a hexagon, as an intermediate option, and also in the form of a star, but they are extremely rare.

When using wooden dowels, it is very important to remember two conditions:

1. The dowel should be slightly smaller in diameter than the hole previously drilled in the log or bar. In addition, the fasteners should be slightly shorter than the hole. Only in this case, the wooden dowel will provide a calm shrinkage of the wooden house, it will change dimensions with it, otherwise the crowns may hang on the mountings;
2. The wood for the dowel should be stronger than the timber itself or the log. If pine is used to build a house, then the dowel should be made of a more durable tree, for example, beech or birch. Larch, oak, ash are also used for the production of dowels..

According to SNiP, during the manufacture of dowels, wood of the first or highest grade must be used, without curl, knots and other wood defects. The moisture content of raw materials should not exceed 12%. It is advisable to treat the pins with antiseptics.

There is GOST 30974-2002, which states that the diameter of the dowel must be at least 1/6 of the diameter of the log. That is, if we have a log with a diameter of less than 140 mm, then a dowel is needed with a diameter of 22–25 mm. In this case, the length of the pins is not regulated. Usually they take fasteners with a length of 120-150 mm.

As for the price, one birch dowel 22 or 25 mm in diameter and 1.2 m long costs about 18–20 rubles. One meter of oak dowel with a diameter of 21-25 mm costs about 32 rubles. Usually, a fastener of the desired size is sawn off already at the place of construction of a log house or a house from a bar.