Almost everyone at least once in life has a desire or need to make a hole in something. For example, we want to attach the cornice in the living room or we need to attach a bookshelf – this requires making holes. Mechanical or electric drill helps in most such cases. About how to choose a drill we will discuss in today’s article.
History of drill is long enough. The ancient people like modern, too acutely aware of the need for making holes. First, they took something sharp and twirling it back and forth until it got the desired result. Then, this process has become a bit more mechanical. Mechanical hand drill and after him electric drill was invented after many upgrades and improvements.
What is a drill? The main principle of the drill is that a special nozzle (drill) makes rotational movements and penetrates the surface of the material, as a result we obtain the required hole.
Let’s look closer at the parameters of drills that can determine the choice of this instrument.
1. Drill types.
Depending on the direction of drill motion drills are divided into two types: ordinary rotary drills and hammer (impact) rotary drills.
Ordinary drill can do different holes only due to rotational movements of its drill (rotary drilling).
What is a hammer drill? Drilling element provides translational (drums) motions in addition to rotational motions in hammer electric drill. This means that the drill except rotation around its axis also moves back and forth.
Due to the hammer motion drill acquires the ability to not only make round holes, but also to make small notches (this could be useful for the installation of various switches, etc.).
Ordinary rotary drill used to work with a relatively soft surface (wood, plastic), impact drill can be used when you want to get holes in hard surfaces (brick, concrete layer, etc.).
Most modern drills are hammer drills, but they have a special switch which allows enabling or disabling the hammer function.
2. Drill power.
Electric motor, which provides a drill nozzle rotation, is built in electric drill. The strength, speed and therefore the productivity of drill depends on its motor power.
Small household models can have power of 250 watts, while the professional drills may have power 1500 watts or more.
We consider the usual drills that are powered from the electrical outlet in this article. In cordless drills that are powered by built-in battery the power is usually lower.
The most common manufacturers produce 550-800 watts power drills. You can pay your attention to this power range.
3. Max speed and beat frequency.
I have already mentioned about speed of rotation in the article about electrical angle grinder. This rate is an important characteristic for drills by analogy. However, the drills speed figures are slightly different from this indicator in angle grinder.
Almost all drills have a maximum rotation speed of 2600 to 3000 rpm.
Greater maximum speed is better, but equally important is the ability to regulate this speed.
Special drill speed regulator, with which you can regulate the speed of drill element, is provided in most models for this purpose. Therefore it can be recommended to choose the drill with only with such regulator.
Beat frequency is an important indicator of hammer drill. With greater beat frequency tool will processed surface faster. The most common beat frequency ranges from 43,000 to 48,000 beats per minute.
If you need a really universal tool, you can choose a drill that has a maximum rotation speed of 3000 rpm and beat frequency of 48,000 beats per min.
4. Maximum drilling diameter.
You may need to make holes of various diameters, for which there are drills of different diameter. However, it should be noted that the process of drilling accompanied with a heavy load on working parts and drill motor.
The larger drilling diameter causes greater load on the tool. The possibilities of drill are not endless and if overloaded will happen it can break down. To avoid this for each model specified maximum drilling diameter for various materials.
For example, a drill Bosch PSB 28 RE maximum diameter for drilling in wood is 20 mm and for drilling in steel – 10 mm. It should be noted that this are the maximum critical parameters and if the drill will continually work with such diameters, it can break down too.
Normal operating drilling diameter are usually slightly less than the maximum.
5. Drill chuck types.
Electric hand drill chuck is a part of the tool that captures drill. There are two types of chucks – key chucks and keyless chucks.
The key chuck fixes drill using a special key.
Fixation in keyless chuck carried out manually without any additional devices. The advantage of the keyless chuck is the possibility of a quick drill change.
If you want to buy a low power drill and will use it to “soft” surfaces, keyless chuck allows you to save considerable time. But if you buy a medium or high power drill and will use it for all occasions it is better to choose key chuck, because it is more reliable.
6. Reverse movement ability.
As we know drill rotates clockwise when drilling, while delving into the surface. In order to pull the drill back we need to make some effort, while it is most easily removed when it rotate in the opposite direction to the direction of drilling.
Reverse function allows you to rotate the chuck in the opposite direction, making it easy to pull the drill. Reverse can also be useful if a drill is used as a screwdriver, because it can unscrew screws in this mode.
Besides these parameters when choosing a drill you can check for such additions as:
– Auxiliary handle. Auxiliary handle allows you to comfortably hold the drill with both hands, thus increasing the efficiency of drilling.
– Drilling depth stop. It’s a small lineup with scale, which is often inserted in the auxiliary handle. This limiter is used most often when you are afraid that something can be drilled through, but it is not required.
– Drill case. Some drills are sold in plain cardboard boxes. These boxes are broken over time and you will not have where to store drill. Major manufacturers make their products complete with a special plastic (sometimes metal) case. You can carry and store your tool quite comfortable in this case.
Well, the main drills characteristics are listed. I hope this article will help you to buy the best electric drill.