How do I learn to drill

Correct drilling: tips for perfect drill holes

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Before moving into the new building, the walls are still intact. But that is changing, because holes have to be drilled to fix cabinets, mirrors and other things. If you drill correctly, you will avoid unnecessary damage to the new walls.

There are holes to be drilled everywhere in the household: a cupboard must be hung in the bathroom, the tall cupboard in the living room needs a wall bracket, the mirror in the hallway needs a hook. But sometimes there is a problem with drilling. has some advice at hand.

The underground

Essentially, a do-it-yourselfer has to deal with three groups of materials when drilling into a wall:

  • Low hardness: lightweight walls. Walls made of plasterboard or chipboard that are screwed or nailed to a stand system. There is partially a cavity behind the drywall. Prefabricated houses or partition walls in solid buildings are often constructed in this way. Old buildings often still have so-called Rabitz walls: a mixture of blast furnace slag and cement was stiffened with wire mesh.
  • Medium hardness. These include above all walls made of burnt mud bricks, huts, sand-lime bricks or aerated concrete.
  • Great hardness. Reinforced concrete, as you know it from prefabricated buildings, tiles, clinker bricks and concrete blocks.

The distinction between the materials or at least the degree of hardness is crucial when it comes to the right tool and the right method. If you have no idea what material the wall to be worked on is made of, you should make a careful test hole. If red drilling dust appears, it is brick, concrete appears gray and white flour indicates gypsum, sand-lime brick or aerated concrete.

The right tool

The selection of the most suitable hand drill and the right drill is based on these three material groups. In the hardware stores these tools are sorted according to the material groups.


A Twist drill for wood is enough to drill holes in plaster, wood or chipboard. Sufficient for most solid walls drill completely off, at the top one ground hard metal piece is soldered on. In terms of price, this is significantly cheaper than a drill made entirely of hard metal. Do-it-yourselfers recommend granite bits for concrete walls. They can also be used to drill into most natural stones.

If you also want to work on tiles or clinker frequently, you should ask Titanium drill bits or those with Diamond tip to grab. Both are the most expensive choices, but justify their use with high durability and easy, precise work.

drilling machine

A simple drill is sufficient for light, wooden or soft walls; it can only do one thing: so-called rotary drilling. In this case, cordless drills can also be used without any problems.

Impact drills are recommended for walls of medium hardness. Not only do you turn the drill, you also use a switchable hammer function to make it move slightly up and down, known as a "blow". To do this, however, you have to press the machine firmly against the wall. The hammer effect is essentially triggered by the user of the machine and in practice is more likely to be perceived as vibrations. This is due to the fact that the beat frequency with these devices is quite high, while the stroke is quite small.

In the case of very hard materials, it can quickly happen that the drill gets too hot, that no acceptable advance can be achieved or that it only takes a lot of force. In such cases a Hammer drill ago, often too Hammer drill called - preferably with a pneumatic hammer mechanism. The impact pulse is transmitted to the drill chuck, i.e. the holder for the drill, by compressed air. The bracket is usually a so-called SDS system, in which the drill is not screwed on, but only plugged in. Longitudinal grooves on the shaft ensure that the drill is held in the chuck and can slide. Such machines have a switch for rotary movements with and without impact, so that they can also be used for normal drilling. If you only set the impact and omit the rotary movement, it can be used for chiseling work and replaces hammer and chisel.

It is very beneficial if the respective machine has a Speed ​​controller disposes. This is either a setting wheel or the speed is controlled via the on / off button.

Correct drilling

When the tool and the substrate are well coordinated, the next step is to drill properly.

  • Before starting the drill, it is important to be precise to measure and mark where the hole should go. If there are several holes, a spirit level must also be used.
  • Anyone who does not have photo documentation of Electricity and water pipes has done, you now have to take other steps to ensure that you do not hit any lines when drilling. Locating devices, also known as line finders or wall scanners, are available in stores for this purpose. Their price ranges are considerable: the simplest device is available for less than 10 euros, the middle price range is 20 to 40 euros and professional locations cost around 250 euros or more.
  • Around exact To stay, you should first work your way forward a few millimeters at a slow speed and without impact. Only then is it continued with impact and higher speeds. Alternatively, you can pre-drill with a thinner drill from about a third to half the planned diameter. The small hole will help center the larger drill bit.
  • In new buildings should erupting drill edges actually does not occur. But this can happen in old buildings. Then soak the drilling site with colorless latex or slightly diluted cold wood glue, let it dry and then drill. This works particularly well if you have first pre-drilled thinly. Chipped areas around the drill hole can also be filled after inserting the dowel.
  • When drilling, it inevitably trickles Brick dust or Concrete dust from the wall. This can be eliminated immediately if a helping hand holds a vacuum cleaner under the borehole. A paper bag or a damp cloth can also help if necessary.
  • The Depth of a borehole depends on the screws and dowels that you want to use afterwards: the screw should be about five millimeters shorter than the dowel and the drill hole in turn about ten millimeters longer than the dowel. Some drills have a depth gauge; This is a movable iron rod that lies parallel to the drill and prevents deeper penetration when it hits the wall. The maximum drilling depth can also be marked on the drill itself with a piece of adhesive tape.

Special case tiles

In the bathroom, it is not always possible to avoid drilling through tiles, for example to hang up cupboards. You should always try to place the drill hole at a joint, but unfortunately that is not always possible. The fine ceramic plates are easy to penetrate with a stone or widia drill - if it weren't for the hard glaze. The drill moves back and forth on them as soon as it turns. It is therefore advisable to pre-drill with a small stone drill with a diameter of two or three millimeters, but never with a hammer! You start with very low speeds and increase these when the drill is securely seated. The larger drill is then also allowed to run very slowly until the glaze has been penetrated. The wall can then be machined again with impact.

Breakthrough special case

If electrical cables or pipes are to be laid, a wall sometimes has to be completely broken through. A twist drill is sufficient for narrow openings, but a so-called drill bit, also known as a core drill, is necessary for sewage pipes, for example. This is a hollow cylinder with cutting edges made of hard metal or diamond chips at one end. As a rule, the diameters for home improvement are between 30 and 200 millimeters. However, it is not worth purchasing such tools for a one-time use. Hardware stores or rental stations help with rental drills.

Steffen Malyszczyk

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