How to choose a good cordless drill screwdriver

Punchers, drills, screwdrivers - these tools are sure to find application in the household. Manufacturers are constantly working to improve their products and produce new models. And today, the functions of a perforator, a drill and a screwdriver can be combined in one device, powered by a small battery. You just need to know how to choose a cordless drill driver, and you can forget about the wires and the inconvenience associated with them.

Scheme drill-screwdriver.

Which battery is better?

Being able to work without being tied to a network is a big advantage. But at the same time with the convenience, there are some difficulties associated primarily with the choice of a suitable battery. Drill screwdriver can be equipped with the following types of batteries:

1. Lithium ion
2. Nickel-cadmium.
3. Nickel metal hydride.

Gradually, more modern and improved polymer batteries are entering the market, but they have not yet become widely used due to their relatively high cost.

Lithium-ion battery circuit.

Thus, first of all, you need to understand the features, advantages and weaknesses of each battery, which can be equipped with a drill screwdriver.

Nickel-cadmium batteries are a real veteran of this market. They were among the first to be used as a power source for hand-held power tools. The cost of such batteries is relatively affordable, they feel great in almost any weather. Even under high current loads, such a battery will serve for a long time. On average, a nickel-cadmium battery can withstand 1000 charge and discharge cycles.

These batteries have their drawbacks. First of all, you must strictly observe the conditions of use of the battery. Before you put the battery on charge, it must be discharged to a certain level. If this is not done, the capacity of the product will decrease. This “memory effect” is the main disadvantage of such batteries.

Another serious disadvantage of batteries of this type is their relatively high harmfulness. Gradually, they are abandoned, but you can still find commercially available drills and other power tools.

Instead of nickel-cadmium batteries, nickel-metal hydride batteries are increasingly being used. They are safer for health and the environment. Among the advantages of such products can be identified high charge capacity. Other things being equal, they will have noticeably less weight. Nickel-metal hydride batteries are deprived of the “memory effect”, the instruction does not prohibit keeping them in a charged state, which is very convenient in everyday life when there is a need for a sudden minor repair. However, after some time, the battery capacity is still reduced.

Comparison of nickel-kamidium and lithium batteries.

Among the shortcomings can be identified instability to freezing temperatures and high currents. The average number of charge-discharge cycles does not exceed 500. Thus, in practice, nickel-metal hydride batteries, on average, serve 2 times less than their nickel-cadmium counterparts.

Manufacturers see great potential in lithium-ion batteries. They have an even higher capacity than nickel analogues. Deprived of the "memory effect" and charged for the minimum time. But there are also disadvantages:

1. Inoperability at sub-zero temperatures.
2. Relatively low service life.
3. Higher, compared to nickel batteries, price.
4. Low resistance to high load currents.
5. Fear of complete discharge.

The last 2 shortcomings now allow to solve electronic protective schemes.

Battery capacity and versatility

When choosing a cordless drill screwdriver need to pay attention not only on the type of battery, but also on its capacity. The capacity of the instrument on one charge directly depends on the capacity. This indicator is measured in ampere-hours (A * h). Complete with semi-professional and professional drills usually comes with 2 batteries. This increases the convenience and productivity of work.

Battery comparison chart.

You also need to pay attention to such a characteristic as the voltage on the batteries. Household variations usually work with voltage up to 12 V. The disadvantage of high-voltage units is the presence of a larger number of elements, which increases the overall weight of the instrument and makes the work not as comfortable as with a household level unit.

For a household screwdriver drill, it is recommended to additionally buy a second battery, if it is not included. However, in the presence of several power tools, a lot of batteries simply become inconvenient to store. Manufacturers have taken this into account and made everything much more convenient. Now the power tools of the same manufacturer, presented in the same line, as a rule, are able to work with the same battery and charge from one device. This allows you to significantly save space for storage of components and, of course, money. If, for example, the perforator battery fails, it will be possible to use the battery from the drill without any problems instead. Yes, and monitor the status of 2-3 batteries is much easier than a whole arsenal.

Most modern models of screwdrivers are equipped with 2 batteries at once. The cost of such kits is somewhat higher, but it makes it possible to make the work more productive. However, if you do not plan to use your drill screwdriver too often, there is no point in purchasing such a kit.

Scheme of the device of the professional perforator.

Additionally, you need to pay attention to such an indicator as the battery charge time. Previously, manufacturers have produced such devices that provide a full charge for 3-5 hours. Currently, charging takes much less time. Professional units charge in an hour, and sometimes even in 30 minutes. However, the less time it takes for the charger to fully charge the battery, the more demanding it is for cooling. For this, ventilation ducts are created or miniature fans are installed. They are placed inside the power supply or directly in the battery design and do not interfere with the work.

Torque and other important features

As for the technical characteristics of the drill of a screwdriver, one of the most important among them is such a parameter as torque. This characteristic reflects the rotational force that a particular tool can create. It is expressed in N * m. The higher the torque, the more versatile the tool and the greater the number of different jobs that can be performed with it. If your plans do not include the drilling of steel and concrete structures, you can buy a drill with a small torque screwdriver. Such a tool will weigh less and cost less.

Modern stores of power tools provide a convenient opportunity to test the proposed products in action. For this set of demonstration stands. Anyone can try to work with this or that tool before buying. This greatly facilitates the selection.

Important characteristics also include the maximum drilling diameter in hard and soft materials. Select this parameter individually, taking into account the peculiarities of the forthcoming works. Pay attention to the maximum diameter of the screws.

Drill screwdriver must be equipped with a clutch for switching torque. The ability to adjust significantly extends the scope of work: from simple screwing in screws to drilling holes in concrete and metal products.

Diagram of the internal structure of the drill-screwdriver.

Another important parameter of any drill screwdriver is the speed. The instrument in question is usually a two speed. Screws, as a rule, are twisted at a frequency of up to 500 rpm, holes are drilled at a speed of more than 1000 rpm.

It is better that the drill screwdriver had a reverse. He will allow to start rotation in the opposite direction. This makes it possible to unscrew the screws and with fewer losses to get the drill if it is stuck in the material.

What you need to know about the engine and the cartridge?

When choosing a cordless drill screwdriver, pay attention to the type of engine and its characteristics. Most often, such a tool is equipped with a brush motor. Also on sale are models with more modern brushless motors, they are also brushless. Their design is devoid of brushes that create sparks and are erased. Everything is controlled by electronics. The advantages of brushless motors include:

1. Higher efficiency.
2. Longer service life.
3. No need to periodically replace worn brushes.

The disadvantage is the higher cost of the drill, equipped with this kind of engine.

Special attention should be paid to this element of the design of the cordless drill screwdriver, as the cartridge. Cartridges are single and dvuhfutovymi. In drills with dvuhmuftovymi chucks tooling is established by clamping and tension. The user will have to hold the cartridge with one hand and rotate the wheel with the other. This is quite doable, but not very convenient. Therefore, most modern models are equipped with quick-release single-footed cartridges. In the case of such a drill, there is no need to hold the chuck to clamp the drill. This advantage is provided by a spindle lock. When it is operating, the lock will be absent, but when it is turned on, the electronics must be stopped. This greatly simplifies the process of replacing the drill. You just need to insert it into the cartridge and tighten.

Diagram of the device cartridge drill.

This design of the cartridge improves the convenience and versatility of the power tool, but at the same time, it creates certain inconveniences due to the increase in the overall size of the unit. In order to eliminate this inconvenience, manufacturers complete their products with quick-release cartridges. To remove an item, just pull the ring and set the bits.

Pay attention to such a figure as the maximum drilling diameter. It is indicated in the passport of the cordless drill.

As a rule, the higher the torque, the larger the diameter of the hole that the drill / driver can drill. It is not recommended to exceed the passport indicators: this can lead to breakdown of the power tool.

Additional options and features

Modern drills screwdrivers can have many additional features. Each of them in one degree or another increases the cost of the tool, so be sure to consider whether each of the possible additions will be useful to you in order not to overpay money in vain. The most common and useful additions are as follows.

The possibility of drilling with a blow. It will be useful to those who have to drill bricks, concrete and other solid materials. In battery models is relatively rare. The use of a more powerful engine and battery is not the best way reflected in the size and weight of the tool. If you often have to process solid materials, it is better to buy a separate punch.

The function of the smooth speed control will allow you to change the speed by changing the force of pressing the start button. Convenient when doing some work, for example, creating non-through holes.

If you occasionally have to work in poor light or at night, pick up the model of the drill with a flashlight.

Thus, when choosing a cordless drill screwdriver you need to take into account many important features. Pay attention to each of them so that the acquired cordless drill becomes your reliable assistant. Have a good choice!