How to choose a drill for a dowel?

For the purpose of attaching suspended structures to a surface consisting of a material that is dense or loose in its structure, they are used special dowel fasteners. The reliability of such an attachment largely depends on how correctly the size and diameter are chosen. dowels... But that's not all - if the hole for mounting the dowel attachment is too large, a strong and reliable docking of the dowel with the wall will not work, the device will loosen over time and will soon fall out.

In order to choose the right drill for the dowel, you must be guided by the following principles.

1. First of all, you will need define the structure of the wall surface, with which to work: dense or loose, what material it consists of, and in what state this material is at the time of installation. It is also taken into account whether the work surface has any outer coating. It is also evaluated for density and operational condition at the time of installation.
2. Select the size of the dowel - for this purpose, it is determined how much weight of the structure is to be supported by the installed fasteners. Lightweight suspended structures are installed using the smallest diameters of fasteners, and heavy products, the weight of which reaches 100 kg, must already be installed using anchor bolts - in this case, the dowel is not used.

To select a drill that will make a hole in the wall for installing a dowel attachment, take into account the size of the selected diameter of this fastening device... For ease of completing such a task, the wizard are guided by marking dimensions, which are available for both the dowel and the drill. In addition, the dowel mounts also have ultimate strength information, which also needs to be taken into account when it comes to the installation of heavy suspended structures.

First drill should have a slightly smaller diameter than the dowel. It is fixed in the chuck of an electric drill with a blow and a hole is made in the wall to the required depth. Then take second drill, the diameter of which is equal to the diameter of the dowel attachment, and the expansion of the hole made to the desired size is performed - this work is no longer performed on the shock, but in the usual mode of installing the electric drill.

If you have to work with large drill diameters, then instead of an electric drill it is best to use perforator.

Using 2 drills of smaller and larger diameters for work, you,

• you will not overload your power tool,
• in this way, you can get a mounting hole, which will have the required diameter, which will exclude the possibility of twisting the installed dowel in the wall, which means that it will ensure reliable installation of the suspended structure.

For working with in-situ concrete experts recommend the use of drill bits or diamond-coated products.

This approach gives the possibility of tight fit of the fastener into the prepared hole, and even with small damage inside the wall, occurring in the process of drilling loose material, the dowel will fit as tightly as possible.

Concerning the length of the wall opening, then it is usually made 3-5 mm longer than the length of the dowel. This is necessary so that during the installation process, the tight fit of the fasteners does not interfere with the dust accumulated when drilling the wall in the hole, which cannot be completely removed.

Select the correct drill diameter based on the weight of the suspended structure. The higher this indicator, the more durable the dowel fasteners must be. The ratio of the diameter of the drill and the dowel will help determine the following table.

Thus, according to the above table, we see that for a 6 mm dowel, you need to drill a hole with a drill of the same diameter, that is, 6 mm, and for an 8 mm dowel, you need to take a drill equal to 8 mm.

Carrying out installation of lightweight suspended structures can be carried out using a dowel with a diameter of 4 to 6 mm. Such fasteners will be enough to hang a picture, a mirror, a wall clock, a small bookshelf on the wall. As a rule, such a low weight of the suspended structure is distributed between two attachment points, and sometimes one attachment point can be dispensed with. In this case, the length of the wall hole for inserting the dowel into it is made from 3.5 to 6 cm.

While doing installation of suspended structures weighing more than 5 kg, you will need to take a dowel with a thickness of 8 mm. In this case, the length of the mounting hole should be from 5 to 7.5 cm.If we mount the structure on loose foam concrete, then the drill diameter is chosen 6 mm, and the hole depth is made at least 8 cm.

All suspended structures weighing more than 10 kg are considered heavy. In this case, the dowel diameter can be 8-14 mm. To prepare the hole, a drill with a similar diameter is chosen and a perforator is used in the work, and the drill is taken with a victorious tip. In order to securely fix the suspended structure, it is recommended to make at least 4 attachment points, or even better if there are 6. Heavy suspended structures can only be mounted on solid wall surfaces, as the loose material can begin to collapse due to the heavy load through the dowel.

If the weight of the suspended structure exceeds 60-100 kg, then dowel fasteners are not used for installation, in this case anchor bolts are used, since their degree of reliability is much higher.

Recently, there has been a tendency in the construction market to make a variety of wall surfaces from materials with low strength. This option includes drywall... In addition, low strength is noted and from old brickwork, as well as aerated concrete and wood panels.

If it is required to mount the suspension structure on such a low-strength surface, you will need to purchase a dowel fastener, which consists of a nylon cylinder and a screw. The diameter of such an attachment is more than 10 mm. To obtain a reliable coupling of the structure to the wall, the length of the hole for installation is made at least 60 mm.

Working with loose wall surfaces, the master must remember that an electric shock drill cannot be used in this case, since such a load can cause the destruction of a large section of the wall.Even if external damage will not be noticeable during work, then there is no doubt about the presence of internal violations of the bonds of the material inside the wall.

If we take the diameter of the drill equal to the diameter of the dowel attachment, then a tight fit will not work, and the installed dowel will fall out over time. So that the dowel mount can be driven into the wall hole, it is made a little smaller, but the strength of such a mount will be high and reliable.

When working with an aerated concrete wall, start drilling a hole with a diameter 3-4 sizes smaller than the dowel. Then they take a drill 1 size larger and expand the wall hole, bringing it to the desired diameter. Such drilling with successive expansion makes it possible to preserve the integrity of the loose aerated concrete material and to perform high-quality fastening of the suspended structure without unnecessary destruction.

Watch the video on how to choose a drill for a dowel.