Dowels and the borehole

Dowels are used in almost every household. Nevertheless, little is known about their mode of action. This also means that the efficiency of a dowel depends heavily on the quality of the associated wellbore. What the borehole needs to know about a dowel is summarized below.

The hole for the dowel must be absolutely accurate

Drilled hole, dowel knocked in, screw screwed in. Done for most people is the setting of a dowel. It is quite common that a dowel is not sitting properly or the hole is too big. Then other solutions, such as the setting in of anchors, have to be found.

There are some data that are closely related:

  • Size of the dowel
  • Length and size of the screws
  • required load capacity
  • Type of dowel

The borehole and its requirements

Most commonly used are so-called plastic expansion anchors. The borehole must follow exactly the dimensions of the dowel used. The size of the dowel depends in turn on the required load capacity. This data can be found on the packaging of dowels in tables.

The size of the screw

The screw suitable for the dowel is about 10 mm longer than the dowel. The strength of the screw can also vary. This data can also be found in the above-mentioned table on dowel packaging. The borehole, in turn, should be about 10 mm longer than the dowel. This results in certain minimum requirements.

The size of the drill

The diameter of the borehole must correspond to the anchor size. That is, for a size 8 dowel, you must also use a size 8 drill bit. But now comes an important differentiation: each drill is not equally suitable for every surface. There are significant differences here. Similarly, when drilling itself (only drilling by rotary motion and / or with shock).

The right drill bit for the material to drill

For concrete substrates you need a particularly hard stone or concrete drill bit. For aerated concrete, a conventional stone drill is suitable. However, you do not need a blow for aerated concrete, but you do need concrete. Without a beat you also drill in bricks.

In addition, you should use special brick drills, as they are equipped with a cutting edge. Thus, in particular with hollow bricks uncontrolled breaking of the brick bridges is avoided. But even with bricks this advantage comes into play.

Tips & Tricks

We have summarized detailed information on all the requirements for borehole and size as well as other peculiarities under "Dowel sizes and dimensions".

Video Board: Drilling holes in wood. What drill bit to use. Drill holes in MDF, chipboard, timber, plywood.