What to look for when buying drills

Cordless screwdrivers, drills and various similar power tools can be found today in almost every household. While the choice of the correct screwdriver bit is usually determined by the screw, some are over-demanding in choosing the right drill bit and often resort to the wrong drill. Most of the time, the result is that there is simply no drilling progress during drilling. But if you are less fortunate, using the wrong drill and the wrong drilling technique can seriously damage the material and cause high costs.

The large number of special cases when drilling makes it almost impossible to present all drills in a single article. But this article is to cover the two most common in the household situations with the topics of drilling in wood and drilling in stone / masonry at least. In addition, we have hidden a few insider tips that can significantly facilitate drilling.

Drilling in wood

Who wants to drill holes in wood, z. As in the construction of a shelf or piece of furniture, which requires wood drills, as the name easily reveals. But what makes a drill a wood drill and what makes good wood drills?

When we think of drills, we usually mean twist drills . Again, the name does not come by chance, because as seen in the picture, the drill is arranged spirally. But strictly speaking, this spiral has nothing to do with the drill itself. During operation, the spiral acts as a kind of conveyor belt, which carries the sawdust out of the borehole. This task is incredibly important because otherwise the hole would quickly clog and the drill overheat and break it. Nevertheless, the actual task of drilling is the drill head. That's the entire tip of the drill bit. Looking at it more closely, you can see two components: The centering tip and the cutting head. The former is not as pronounced in any other drill as in the wood drill. Wood is a relatively soft material – at least compared to metal or stone – so the thin tip can be quite well pressed into the wood. The actual drilling then makes the cutting head, which is arranged around the outside of the tip. In this case, it is therefore particularly important to have a sharply ground edge. When the twist drill is the right choice becomes clear when we look at the other wood drills.

In addition to the twist drill, you often also find Forstner drills or hole saws . Both have some similarities, but also serious differences. First of all, you always reach for one of the two drills if you want to drill holes with a particularly large diameter. What does big mean? Of course, there is no clear limit, but roughly speaking, it is hard to find twist drills above 15mm and it is just as difficult to find Forstner drills or hole saws below 15mm. So it's clear when to pick these two types of drills, but you take which one? For this you have to take a closer look at how the two drills work. A hole saw is nothing more than a saw blade arranged in a circle. The differences become very clear if you drill only half the thickness of the material with one of the two drills. In the hole saw, we now find a circular depression in front of about the thickness of the saw blade. In the middle but was – except a small center hole – no material removed. Thus we also directly recognize the decisive advantages and disadvantages of hole saws: On the one hand, we can – because we only remove very little material – with very low drilling capacity also "saw" very large bore diameter. On the other hand, such a hole makes little sense if the material has not been completely sawn through.And this is exactly where the Forstner drill comes into play: not only does it cut out a round piece of wood, but it also – like the twist drill – cuts material evenly over the entire drilling diameter. This requires a lot of power from the drill, but at the same time we get a uniform depression. So should z. B. a blind hole to be drilled, one must resort to the Forstner drill urgently.

Shopping tips Wood drill

So let's summarize: If you want to drill thin and deep holes in wood, you should resort to a twist drill. A twist drill suitable for wood can be recognized by the pronounced centering point. Who,

on the other hand relies on larger diameter, should resort to a Forstner drill or a hole saw. If the material is not completely drilled through, but only a blind hole arise, you have to grab the Forstner drill. The following applies to all types of drill: The drill head should be sharpened very sharply, because it does the cutting work!

Drilling in stone and masonry

If wood is drilled in stone or masonry instead of wood, it gets a bit more difficult. Stone is harder and therefore requires higher quality drills, on the other hand masonry can be damaged much easier than one would expect.

Cheap vs. special drills

It is therefore all the more important for the stone drill not to save on its quality. Our picture shows on the left side no-name stone drills from the hardware store and on the right high-quality drills from Bosch from specialist retailers. If you look more closely at the tip, you will not notice a real cutting edge on the cheap drills. The tip is dull and not ground in one direction. So this drill will generate a lot of noise, dust and possibly smoke, but only very little drilling progress. Many would now intuitively compensate with the impact drill function. The correct thing, however, would be the use of a high-quality drill. The drills in the right half of the picture show a distinct cutting edge, the cut of which is clearly visible. This drill will almost slide through the material compared to the other.

How much a high-quality drill makes up, shows the following video from the cordless screwdriver test of werkzeugcheck.com. At 1:59, a high-quality drill is used to drill a concrete screwdriver into concrete that is once again harder than most bricks or masonry.

Another interesting point is addressed in the video: The difference between regular drilling and impact drilling. We will discuss that in the next section:

Drilling vs. Impact Drilling vs. hammer drilling

In addition to the classic drilling, which consists only of a turning of the drill, there is also the impact drilling and hammer drilling. Impact drilling generates impulses to the drill with the aid of a hammer mechanism, depending on the speed. This increases the maximum torque and it can be drilled faster in particularly hard material. In contrast, hammer drilling additionally moves the complete drill back and forth in addition to the rotary motion. One can imagine this imaginatively, as in addition hit with a hammer on the back of the drill, the machine is then again pulled a bit out of the hole and hit again on the drill. Except that this happens very often per minute.

Hammer drilling allows significantly faster drilling progress thanks to the three-dimensional drilling movement, but it also harbors some dangers. Drilling hammers should only be used on concrete or very solid rock. You should never drill into bricks with a hammer drill. These have very fine hollow chambers for purposes of thermal insulation. These fine walls between the chambers are quickly destroyed by a hammer drill.

Shopping tip Steinbohrer:

If there is little drilling progress, the first thing to do is to check the quality of the drills. These should then be replaced by sharp-edged special drills. Never should the missing sharp edge of a bad drill be compensated by the use of more power or even a hammer drill.This damages the material and can cause great damage, especially in modern bricks.

Conclusion to the drill purchase guide

Important is the choice of the drill suitable for the desired application. As so often in life, quality does pay well for the drill. If you look closely at the drill, you should see a clear, sharp mark. If the drill already looks dull when you buy it, it will not be much fun. Never compensate for blunt drills with larger drills. As the video above clearly shows, even a cordless screwdriver can drill in concrete if the drill is sharp enough.