The Government of the Russian Federation has expanded the list of technically complex goods, adding a new position - electrified tools (hand-held and portable electric machines) (Resolution of the Government of the Russian Federation of September 17, 2016 No. 929 "). These, for example, include electric drills, electric grinding and electric cutting machines, electric wrenches, electric hammers, etc. ().

Such a change means a special procedure for regulating consumer rights when defects in goods are detected. In particular, they can refuse to execute the sales contract and demand a refund of the amount paid or exchange the goods for a similar one, but as a general rule, within 15 days from the date of sale (clause 1 of article 18 of the Law of the Russian Federation of February 7, 1992 No. 2300-I ""; hereinafter referred to as the consumer protection law).

But at the same time, these actions can be performed after 15 days, but only in the established list of cases: if a significant defect in the product is found (for example, which cannot be eliminated), if the deadlines for eliminating the defects are violated. This also applies to cases where the product cannot be used during each year of the warranty period in aggregate for more than thirty days due to the repeated elimination of its various defects ().

If the seller, when concluding the contract, agreed that he was selling goods with defects, are the relevant requirements of the buyer subject to satisfaction? Find out from the material "Buyer's rights upon detection of product defects" in "Home Legal Encyclopedia" Internet versions of the GARANT system. Get it for 3 days for free!

By the way, technically complex goods at present, including: digital photo and video cameras and lenses to them, refrigerators, computers, game consoles with a digital control unit, wrist and pocket mechanical watches, as well as electronic, etc. The same applies to some vehicle - cars, motorcycles, floating vehicles with an electric motor and others (Resolution of the Government of the Russian Federation of November 10, 2011 No. 924 "").

December 14, 2016 No comments

The screwdriver has become today one of the most demanded tools among professionals and DIYers. It will come in handy when assembling furniture, assembling plasterboard and plywood structures, roofing with metal tiles and other works. Let's tell you more about this tool.

The screwdriver is manual electric tool for installing or removing fasteners and drilling. A screwdriver looks like a drill, and the principle of operation of these tools is also similar: the motor located in the housing, through the gearbox, drives the nozzle, which does the work. The difference lies in the source of energy (the screwdriver operates on direct current) and the lower rotational speed transmitted to the attachment. The latter is due to the fact that the screwdriver was initially adapted to work with fasteners, at which high speeds are not needed. True, modern screwdrivers are less and less different from drills in this parameter. No wonder that most manufacturers position their tools as multifunctional, calling them drills and screwdrivers.

On the body of the tool there is a start button, a reverse button, a torque setting clutch and a speed switch.

Here, some screwdrivers have a backlight. The battery is inserted into the housing from the bottom of the handle and is securely fastened there with latches. This arrangement contributes to a good balance of the instrument.

SCREWDRIVER DEVICE:

• 1 - keyless chuck;
• 2 - torque setting clutch;
• 3 - speed switch;
• 4 - backlight;
• 5 - power button;
• 6 - reverse button;
• 7 - battery;
• 8 - battery discharge indicator.

The chuck is designed for attaching attachments (bits and drills) and transmitting rotary motion to them. The most common keyless chuck, which allows you to easily clamp the bit without the use of additional tools.

Manufacturers also produce specialized power tools in a line of screwdrivers - for example, today's popular electric screwdrivers, which are small in size and low in power. They will do fine with small repair work in the apartment, in the country. Wrenches, unlike them, have great power, they will help to unscrew, say, a rusty bolt when removing a wheel from the car.

Torque setting clutch and speed switch.

Rotating the torque clutch, the desired value is set opposite the risks on the screwdriver body.

Double sleeve keyless chuck. When installing and removing nozzles, the couplings rotate in different directions.
Additional collar for setting the operating mode of a powerful screwdriver (twisting, drilling, hammer drilling).

The electric screwdriver is perfect for small repair jobs. The impact wrench has increased power and can become a construction assistant.

Main characteristics of the tool

When choosing a screwdriver, first of all, you need to pay attention to two parameters - torque and rotation speed. The torque value shows how much force is applied to the screw (drill) being driven during operation. This will determine, for example, the hole
what diameter this screwdriver is able to drill. In household tools, the torque is 10-16 Nm.

For professional models, this figure can reach 130 Nm. The rotation speed of household tools is in the range of 400-550 rpm. For screwdrivers with a drilling function, it reaches 1,300 rpm. Budget models usually have 1-2 speeds, a professional tool - most often three speeds. In addition, the rotation speed is regulated within one speed by pressing the power button.

The power supply for the screwdrivers is provided by rechargeable batteries. Most often, nickel-cadmium, lithium-ion and nickel-metal hydride batteries are used for these purposes. The output voltage of the batteries can be in the range of 3.5-36 V, but the most applicable range is 9.5-14.4 V. The power of the screwdriver depends on the voltage value, although the dependence here is not direct.

The most important parameter of the battery for screwdrivers is its capacity, measured by the number of hours during which it is able to provide the declared amperage. In addition, the batteries differ from each other in the recharging resource, self-discharge rate, and the presence of a memory effect.

Nickel-cadmium (Ni-Cd) batteries

The recharging resource is within 1000 times, high self-discharge, but they have the lowest price among other types of chargers.

Hybrid (Ni-MH) batteries

The resource reaches 1,500 recharging cycles, they have an increased capacity, are discharged by 1% per month, the price is average.

Lithium-ion (Li-Ion) batteries

They have a reduced discharge time, there is practically no self-discharge, the resource reaches 3,000 recharge cycles, the price is the highest.

Screwdriver bits

When working with the tool, nozzles are used (bits for working with fasteners and drills). The shank of the nozzles is made in the form of a hexagon, which facilitates its installation. The bits can be directly clamped in the chuck or installed in an adapter clamped in the chuck. The working part of the bit is a kind of screwdriver of such a configuration, which depends on what kind of fasteners this nozzle is used for.

Getting started, you need to choose a bit that matches the head of the fastener. The most commonly used cross bits are PH and PZ standards. PH stands for Phillips. PH bits are cross-shaped, universal, they can be used for a variety of fasteners. Sizes - from 0 to A, the most popular is No. 2. The designation PZ is derived from Pozidrive, these are also bits with a cruciform working part. In addition to the main large edges, they have A additional diagonal edges of a smaller size. Thanks to them, the grip area with fasteners is even larger than that of PH-bits. The sizes of such bits are from 0 to A, the most common ones are 2 and 3.

For repairing household appliances and cars, you cannot do without T-bits (from Torx Hole), with which you can unscrew and tighten the screws with a star hole on the head. Flat, or slotted, bits are suitable for working with fasteners in soft material, with not too high a load. Such bits are marked with SL (from Slot).

To work with bolts and nuts, bits with a working part in the form of a wrench are used. They can only be used with fairly powerful screwdrivers (wrenches). Bit sizes are from 6 to 13 mm, but remember that this is the size of the bit itself, not a bolt or nut.

Screwdriver bit sets often include hex shank drills. The angle attachment will help when working in hard-to-reach places. Drill chucks for drills with cylindrical shanks are often used as attachments for screwdrivers.

Additional screwdriver options

Screwdriver options different manufacturers may differ significantly. Their presence increases the convenience of working with the tool, but at the same time they can significantly increase the price of a screwdriver. Therefore, when choosing a tool, you should evaluate the need for one or another option.

• Backlight - one or more LEDs radially located at the front of the housing. Make it easier to work in poorly lit areas.
• Removable handle for easy grip when drilling. It will help when working with a powerful tool, using large diameter drills and drilling with an impact.
• The depth gauge is convenient for serial drilling of the same holes.
• The clothespin makes it easier to fix several attachments on the body or the tool itself on the clothes of the master when moving around the construction site (convenient when working at height).

Models from different manufacturers

High-performance, compact and powerful cordless drill / driver. Suitable for work with fasteners and drilling. Torque can be controlled by presetting the 5-stage torque clutch and drilling position. Has one speed and keyless chuck. The delivery set includes a charger, battery pack, plastic case.

The cordless drill is designed for drilling holes in various materials, as well as screwing and unscrewing screws and screws during assembly work. Thanks to the ergonomic rubber grip and low weight, the screwdriver will become an indispensable assistant in everyday life. The kit includes a rechargeable flashlight, two rechargeable batteries, a charger, a set of bits, a plastic case.

This drill / driver belongs to a new generation of cordless power tools with new Li-lon batteries. The new design of the motor ensures economical energy consumption, which significantly increases the operating time. The ergonomic handle and body are maximally rubberized, which contributes to a secure hold of the tool. For carrying on a belt, the model is equipped with a holster. The kit includes an additional battery, charger and flashlight.

Many of their readers still remember those times when, to work with fasteners or threaded connections, it was necessary to use only screwdrivers and ordinary wrenches. Of course, there is no need to talk about the high productivity of such work. Very often, in order to "drive" the screw into place, it was impossible to do without preliminary, since the efforts of the hand in this case it is not enough forovercoming the resistance of hard wood, not to mention the situation when it was required to "pierce" even the thinnest metal sheet. Several hours of such work - and the inevitable blisters on the hands, and the work barely progressed.

The situation changed radically with the advent of screwdrivers. At first, they were regarded as a kind of instrumental “exoticism” that aroused genuine envy. But very soon these useful tools appeared on the free market, “migrated” to the category of publicly available ones, and today they are included in the obligatory “arsenal” of the overwhelming majority of home or apartment owners. Those who are just now thinking about purchasing such an invaluable assistant should first understand the question of how to choose a screwdriver, that is, what to pay special attention to when evaluating the models presented in a wide range.

The main types of screwdrivers

Under the general name "screwdriver", consumers often mean several types of such tools at once, which, despite the general similarity of functions, still have differences. So, there are three main types:

• Electric screwdrivers.
• Electric wrenches.
• The most versatile - drills... Some models may also be equipped with a shock function.

The most popular demand is for tools that work autonomously, from rechargeable batteries. However, it is quite possible to purchase a screwdriver operating from a regular 220 V / 50 Hz network. Tools with a cord for plugging into an outlet are commonly called “power tools”.

It is necessary to become more familiar with the main types - it will be easier to make a choice, realistically representing the intended nature of the work, their intensity and the load on the tool.

Electric screwdrivers.

Although in terms of their main performance indicators and general functionality, cordless screwdrivers are to some extent inferior to standard screwdrivers, they have their own specific advantages, which make these instruments widely popular among both professional craftsmen and amateurs. These invaluable "pluses" include small weight, compact layout of the device, high ergonomics. This allows the use of cordless screwdrivers in conditions where the use of a larger tool is either associated with great inconvenience or even simply impossible.

Such a tool becomes indispensable on production lines for the assembly of small household equipment, computer and office equipment, it is widely used by masters in the production process or final assembly ... Due to their compactness, ergonomics and low weight, such screwdrivers do not cause quick hand fatigue, and therefore are very convenient for work at height, including, for example, when installing suspended ceilings.

Cordless screwdrivers come in various designs. Many models have a cylindrical body, which, however, is equipped with a swivel joint that allows folding if necessary to concentrate the downforce of the hand.

Other screwdrivers have the usual "pistol" shape, but always very compact, fits comfortably in the palm of your hand.

In addition, very user-friendly models are produced, in which the swivel connection is provided for the working head with a rotating chuck. This opens up the possibility of tightening fasteners or dismantling in the most inconvenient places where it is impossible to start a conventional tool.

The compactness of such power tools is achieved through the use of small batteries, with a voltage usually in the range from 3 to 9 V. Screwdrivers are not exposed to high speeds - as a rule, from 150 to 250 rpm. For their direct purpose, this is quite enough, as well as a tightening torque of about 10 N × m. For the vast majority of fasteners, especially in domestic conditions, such indicators are more than enough. However, there are also more advanced models equipped with a two-speed switch, and allowing drilling work with plastic and wood - the rotation frequency of them can reach up to 600 rpm.

Almost all cordless screwdrivers are equipped with a ”hex bit adapter. Usually, bits for various types of fasteners, as well as small-diameter drills with the same hex shank, are included in the set of the screwdriver itself.

Unlike larger tools, electric screwdrivers are often equipped with a non-removable battery housed in the product body. For charging, a special power supply adapter is used that connects to an outlet.

What's the bottom line? If the owner has a good drill in his toolbox, and he only needs to mechanize the process of working with fasteners, then a cordless screwdriver can be a very useful assistant. In the convenience of such operation, it surpasses a screwdriver, but is significantly inferior to it in functionality.

Electric wrenches

Another type of tool that is very similar to a screwdriver, and even in certain circumstances can be used in its quality, but it still has features that are directly related to its direct purpose.

If the master, according to the specifics of his work, very often has to resort to the installation or dismantling of threaded connections of medium or large diameter, then limiting himself to performing monotonous operations using wrenches means dramatically reducing his labor productivity. A classic example is an assembly production put on stream or, which is closer to private practice, auto repair or tire shops. In addition, in particular, when repairing machines, very often one has to deal with old, "sour" nodes, which are very difficult to unscrew by hand, even after processing with a special compound.

The way out is the use of an impact wrench. Its design is such that, in addition to the usual rotary movement, impulse influences with a certain frequency are transmitted by a special mechanism to the working part of the spindle. In short, these are a kind of "micro-impacts" capable of moving and unscrewing even very rusted nuts or bolts, without violating the integrity of the edges of their head.

Most impact wrenches have a familiar pistol-grip design, but can be additionally equipped with a removable side handle to concentrate the downforce when the connection is pulled off. Nevertheless, there are also "straight" devices, with a working head located perpendicularly - for performing operations in hard-to-reach places.

Of course, such operations require a special drive power - usually it ranges from 350 W for the smallest instruments and even up to 1300 W for professional-grade devices. The rotation speed does not play a decisive role here, and it is usually low. But due to this, a high torque is achieved, which even for "weak" impact wrenches is about 200 ÷ 300 N × m (compare, for example, with the already considered cordless screwdriver!), And in professional-class models with an electric drive power of over 1000 W, this figure can even reach 1000 N × m.

In appearance, nutrunners are very similar to screwdrivers, but they are distinguished by a feature - the absence of a maximum torque adjustment ring ("ratchet"). The working tip of the spindle also differs - most often there is a square adapter for end heads. The dimensions of the square for models of different power can differ - ½ (most often - for models of the household class), ¾ or even 1 inch (for a professional powerful tool), which means that the sets of heads should be purchased accordingly. Although, for this case, there are special adapters.

Some manufacturers immediately provide for increased adapter versatility. So, in the center of the square spindle, there may be a socket for inserting standard ¼ ”hexagons - bit shanks or drills.

But even this does not add much versatility to the wrench. Its specific electromechanical characteristics are still "sharpened" for specific operations. High torque, and even with a pulse mode, can be completely unnecessary and even harmful when working with materials that do not require excessive efforts. And a low rotation speed may be insufficient for drilling.

In a word, an impact wrench, if the specifics of the work of the mother involve its frequent use, will be a good addition to the screwdriver, but it is unlikely to be able to completely replace it in the arsenal of the householder.

By the way, many well-known manufacturers produce tool kits, inwhich includes and drill driver, and impact wrench, which are powered by one set of batteries. Here this is a truly versatile set... True, its cost is quite high, and such a purchase must really be justified.

Drill screwdrivers

This is the most common and most commonly purchased variety of such tools, with increased versatility.

The vast majority of these screwdrivers are made according to the basic "pistol" scheme.

1 - body made of impact-resistant plastic (some professional-grade models have an all-metal body). Inside there is an electric drive with control elements, a well-thought-out air cooling system.

2 - pistol grip. IN quality models has rubberized pads that prevent the tool from slipping in the worker's hand, making the tool as comfortable as possible.

3 - rechargeable battery with a locking mechanism in the handle. In most models, it looks similar to that shown in the figure. However, some modern screwdrivers are equipped with powerful compact-type batteries that are completely hidden inside the handle, making the tool even more comfortable to work with.

4 - start key (trigger). Moving the trigger simultaneously smoothly adjusts the rotational speed of the screwdriver spindle. Usually the trigger is also covered with a rubber or soft plastic pad.

5 - switch for the direction of spindle rotation (reverse). Made so that the switching process is as simple as possible - just enough finger effort.

6 - gearbox switch, which allows you to change the operating modes of the tool - low speed with high tightening force, or, conversely, high-speed rotation required to perform drilling work. This feature is not available on all models.

7 - chuck for clamping the working tool - bit holder or drills. The cartridge design can be different. Some models do not have a chuck - they have a ¼ ”hex socket for standard bit shanks or special drills. The types of cartridges will be discussed below.

8 - chuck clamping jaws.

9 - an essential element of any screwdriver - a mechanism for limiting the torque transmitted to the chuck. Usually it is made according to the "ratchet" principle - when the set tightening torque is exceeded, the clutch slips with a characteristic sound. The number of torque setting positions can be different - from 5 ÷ 6 in inexpensive models to two dozen or more in professional tools. The drilling mode is necessarily provided - when the rotation is transmitted from the gearbox to the chuck without torque restrictions. This mode is indicated by the corresponding pictogram.

10 - modern screwdriver models in They are often equipped with an LED lighting system for the work area. Location LEDs can be different.

Thus, this type of screwdriver is the most versatile, which predetermines its widest popularity among professionals and home craftsmen.

What to look for when choosing screwdriver

When deciding whether to purchase a particular model drill-screwdriver, the future owner of the instrument must clearly understand for what goals it is necessary, what kind operations are planned to be performed by him and with what intensity to exploit. It is these preliminary "outlines" that will become the basic points when assessing the characteristics of devices offered for sale.

Type of batteries and their characteristics

It is advisable to start the consideration precisely with the "energy" of the screwdriver. No matter how wonderful the tool itself is, its performance directly depends on the batteries, the cost of which, by the way, is always more than half the price of the entire set. Surely, many have had to deal with a situation when the screwdriver itself is still quite functional, but the way out of troy power supplies creates a lot of problems. It is far from always possible to find a suitable replacement - many manufacturers do not sell batteries separately, apparently trying to stimulate users to purchase a new set.

The main characteristics of screwdriver batteries are voltage and capacity.

• From voltage directly the power of the electric drive and, accordingly, the maximum torque that determines the functionality of the tool depend. So, on sale most often there are screwdrivers with a battery with a voltage of 9.6; 12; 14.4 or 18 V. This, however, is not the limit - for powerful professional tools accumulators of 20 and even more volts (up to 36 volts) meet. 9 volts still looks a little small even for a household tool. The optimal solution for a screwdriver purchased for household needs is likely to be the “golden mean” - with 14.4 V batteries.

By the way, you can find almost the same from the same manufacturer, differing only in the supply voltage and, as a result, in power indicators. But even in this case, it should be understood that the batteries are not interchangeable - the electric drive is designed for a specific voltage, and exceeding it will lead to its failure.

• Battery capacity is measured in ampere-hours (Ah or Ah - you can find both one and the other designation). Usually, this indicator is indicated on the markings placed on the battery case, next to the voltage.

Basically, battery capacity is a measure of how long a tool can run on one fully charged battery without recharging. Naturally, the larger this value, the less often it will be necessary to interrupt work to replace the power supply and set the cells for recharging.

Typically for household screwdrivers used occasionally, a capacity indicator of 1.2 ÷ 2 Ah is sufficient. For intensive use of this indicator will not be enough - you should look for kits with a battery capacity of 2 ÷ 3 Ah.

Battery performance is directly related to battery types. This issue requires a closer look.

• Nickel-cadmium rechargeable batteries (Ni-Сd )

Due to their low price, such batteries remain the leaders in mass use in middle-class power tools, despite the fact that they are being replaced by more advanced batteries.

Advantages nickel-cadmium batteries are as follows:

• The already mentioned low manufacturing cost.
• High resistance to negative temperatures of operation and storage.
• The only ones in existence, they are not afraid of an absolutely complete discharge. Nickel-cadmium The battery can be stored in a discharged state - and after that it will fully recover after correct charging.

They have enough disadvantages:

• Inability to achieve high specific capacity. The indicator of 2 Ah, at best, will be already limiting.
• Quite short overall "life" - even high-quality Ni-Сd-batteries rarely withstand more than 1000 charge-discharge cycles.
• Such batteries are prone to self-discharge - with infrequent work, you may encounter the fact that a seemingly fully charged battery from storage "sat down" and does not cope with its task.
• The main "disease" of such batteries is the "memory effect". It is unacceptable to charge the battery if it has not fully exhausted its resource. The fact is that when receiving a charge not from "0", the remaining charge level is still perceived by the device as the minimum value. Thus, the capacity of a fully charged battery will spontaneously decrease by the amount of previously unused potential. It is required in one way or another to completely discharge the battery (for example, by connecting a light bulb or a flashlight that is often included in the set of a screwdriver), and only then insert it into the charger. This can be extremely inconvenient, especially in situations when it seems that the power of the tool is already beginning to be insufficient, and "hands reach out" to put the battery on charge.
• Incorrect disposal of waste nickel-cadmium batteries can harm the environment.

Nevertheless , nickel-cadmium Accumulators are considered loyal "workhorses", and are most often installed on household class models. In such operating conditions, their qualities will be quite sufficient.

• Nickel metal hydride batteries (Ni-MH )

Nickel metal hydride rechargeable batteries are an attempt by battery developers to get rid of the main disadvantages of Ni-Cd. But to say with full responsibility that this is a successful step is still impossible.

The advantages of such batteries:

• Their production and disposal are harmless to the environment.
• High charge capacity, which can easily reach 3 Ah. And this is coupled with the more compact dimensions of the battery itself. Accordingly, the power density is also higher.
• The negative effect of memory is no longer so significant, oneako, it was not possible to completely get rid of it.

Negative sides of such batteries:

• Their price is significantly higher than that of nickel-cadmium.
• Short duration of "active life" - the number of recharge cycles rarely exceeds 500.
• Such batteries are distinguished by a high level of self-discharge - the drop can reach up to 10% in the first day of storage after a full charge.
• Battery performance is drastically reduced when working in subzero temperatures.
• It is unacceptable to store such batteries in a completely discharged state.

In short, the high price of such batteries looks unjustified. Better to purchase or a cheaper running option - nickel-cadmium, or do not be stingy and choose a screwdriver with lithium-ion batteries.

By the way, nickel metal hydride batteries have not received much development, and in the sale of tool kits with them are quite rare - due to the low demand for them.

• Lithium-ion rechargeable batteries (Li—Ion)

These are the most modern and, accordingly, perfect accumulators for autonomous power tools.

The advantages of such batteries are as follows:

• There is practically no memory effect, that is, the battery can be recharged at any level of its discharge.
• Among all other batteries, lithium-ion batteries have the maximum charge capacity and power density.
• The charging speed is the fastest.
• But the self-discharge effect is very weak. It is considered the norm that for a year of storage under normal conditions, high-quality lithium battery may lose no more than 20% of its charge.
• The active life, the permissible number of charging cycles of such a battery three times, or even more, exceeds similar indicators nickel-cadmium.

There are also several disadvantages:

• High cost is a rather conditional drawback, since high performance indicators justify this.
• The operating temperature range of lithium-ion batteries is wide enough, and they can be used in frosty conditions (although they lose some in their characteristics). But they will not perceive charging at negative temperatures.
• Complete discharge of the battery is absolutely unacceptable - it will not be charged from "zero". Manufacturers take this drawback into account and equip their products with special built-in electronic circuits that will not allow a full discharge. Moreover, very widespread The trend is to equip batteries with charge level indicators - this makes it easier to visually inspect them.

When choosing the right model, it is best to purchase a kit that includes two batteries. This way you can ensure the continuity of large-scale work - while one battery is on the screwdriver, the second gets charged. However, when using Ni-Cd batteries, you should always keep in mind the need to completely discharge them, so as not to cause a "memory effect".

Very often in the technical documentation of the product, the manufacturer indicates the average duration of charging the batteries - the shorter it is, the more convenient the tool will be to use.

Well, for those users who do not want to mess with batteries, and who are not afraid of the power cord drawn from the tool, it remains to advise to purchase a network model.

The performance of the tool does not suffer from this, but the convenience, of course, somewhat smaller... When choosing, it remains to pay attention only to the length of the cord - so that it is enough for the specific conditions of the intended operation.

Electromechanical qualities of a screwdriver

• A few words about the drive. Most models in the lower price range use the old and proven brush collector circuit. Such engines are quite reliable, but still not without drawbacks. And the main one is significant frictional forces at the place where the brushes adhere to the collector lamellas. Naturally, this is accompanied by a significant release of thermal energy, and the drive heats up quickly enough. In addition, sparking of the brushes on the collector is not excluded, especially if you have to work in conditions of high air humidity.

The electronically controlled brushless motor lacks all these disadvantages. The absence of an additional friction area leads to a sharp increase in tool performance. So. The tests carried out on similar models with completely identical power batteries showed that a screwdriver with a brushless motor performed almost three times more work than with a collector motor.

Some manufacturers (for example, DeWalt) decided to get rid of the motor housing as well - all of its components are located directly in the screwdriver's housing. And this is not a trifle at all - there was a significant gain in the total mass of the instrument, which became much more convenient to work with.

So, if there is a choice between a conventional and a brushless drive, it would be wiser to decide in favor of the latter. True, this is reflected in the price of the instrument.

• When choosing, it is imperative to clarify what materials the screwdriver gearbox is made of. This mechanical assembly bears the greatest stress, and its quality will determine the functionality and overall life span of the entire tool.

This is not to say that plastic gears are of poor quality, but still their resource is less than that of solid metal gears. And deformation of even one tooth on any of the gears entails jamming or complete destruction of the entire kinematic diagram of the gearbox. So it's better to make a choice in favor of metal ones.

• The characteristics of the rotation speed of the working spindle - they are always indicated in the product passport. Chasing too high rates, probably, does not make sense - to perform assembly and dismantling operations with fasteners with an excess of 500 rpm is enough, and for drilling wood or metal - about 1200 ÷ 1500 rpm. Higher speeds are inherent in a professional tool for performing specific operations, and are unlikely to be in demand at the household level.

Speed \u200b\u200bcontrol from scratch to the maximum is produced by changing the pressure on the trigger (key). For a more comfortable performance of basic operations, you should choose a screwdriver that has the ability to switch the gearbox to high and low speeds. Usually the switch is located on top of the case.

• Maximum torque is an important characteristic that will envy the functionality of a screwdriver.

So, for work only with small fasteners, 10 Nm is enough, but it will rather be an electric screwdriver. In order for the screwdriver to perform simple drilling operations, it is better to select a model with a maximum force of at least 25 Nm. Respectively. in the case when more is expected from the tool - for example, drilling wood with crowns of large diameter or metal, choose a screw rt with a torque of 36 Nm and more.

For many consumers, the torque values \u200b\u200bexpressed in newton meters... They can say little. Therefore, in the technical documentation of screwdrivers, the maximum diameters of the drills are usually indicated additionally, separately - for processing metal and wood. This will make it much easier to make the choice.

• Adjustment of the torque (tightening torque) - is available on almost all screwdrivers. As a rule, this is a rotating ring with a scale applied - from the minimum value to the maximum value used for drilling.

When the set force is exceeded, a jib or slip clutch is triggered, and excessive torque is not transmitted to the fastener.

The numbers on the scale show only the ordinal number of a specific switch position as the tightening torque increases, but they have nothing to do (as some inexperienced users mistakenly believe) with the diameters of the fasteners. The drill symbol indicates the maximum torque required to complete the drilling.

• There is a switch for the direction of rotation on all, probably, models - without it, the screw rt just cease to be. Usually located above the trigger. In some miniature screwdrivers (like a cordless screwdriver) two different keys can be provided - for forward and reverse rotation of the spindle.

Chuck type

Most modern screwdrivers are equipped with keyless chucks for easy bit or drill changes.

Keyless chucks can be single or double sleeve.

In a double-sleeve chuck, when installing and removing the working tool, the lower sleeve is held by hand, and the upper sleeve is tightened or, conversely, released. It is even easier to work with a single-foot one - the whole operation is performed with the movement of one hand. True, in this case the screwdriver itself must be equipped with a spindle lock function. Such blocking can be automatic, triggered when rotation stops, or forced (there is a special button).

By the way, when choosing a screwdriver, it is imperative to clarify whether the tool has the option of forced braking of the spindle - when the trigger is released, the rotation should stop immediately. Almost all modern tools are equipped with such a function, but if you still come across an outdated model, the cartridge of which continues to rotate by inertia after the power is turned off, you should not purchase it, since it will cause a lot of inconvenience in work.

Cam chucks, which require a special wrench to tighten, are rarely used with screwdrivers. The key tends to disappear somewhere forever in the course of work, and the process of changing the drill requires a lot of time and additional effort. Nevertheless, many craftsmen include such a chuck in their kit, since sometimes the tightening force of the sleeve chuck may not be enough for drilling requiring significant efforts.

If the choice is made based on the minimum dimensions of the screwdriver and with its predominant use for screwing fasteners, then you can purchase a model without a chuck at all - with an adapter for a ¼ inch hexagon.

In this case, if any small drilling operations are required, you can use a small chuck with an adapted hex shank.

Additional criteria for choosing a screwdriver

Many models of modern screwdrivers are equipped with additional useful functions.

• In addition to the rotational force, an impact force on the tool holder can be provided. This allows drilling holes in some building materials... These screwdrivers have a switch for normal and impact modes. It can be located either on the tightening torque switching ring or separately.

Many hammer screwdrivers come with an optional removable side handle to emphasize the forward drilling force.

By purchasing a similar screw rt, It should still be quite realistic to imagine that he can cope with a brick wall or made of some kind of lightweight concrete (gas silicate). If you need to drill holes in reinforced concrete structures, for example, in the walls or ceiling of a panel house, then it is better to have a perforator for such operations.

• The presence of a pulsed mode of operation of the tool can be of great help in work - by analogy with impact wrenches. This allows you to cope with sour threaded connections or precisely mark the beginning of the drill entry into dense material.

The switching on of the impulse mode can be on the torque adjustment ring, or it can be performed as a separate button, which is pressed as needed.

• Additional convenience during work will be the presence of built-in backlight. LED "flashlight" can be located coaxially to the body, under the cartridge. However, as practice shows, this is not always convenient - the cartridge itself can shade the area of \u200b\u200bwork.

Another location of the flashlight is at the bottom of the pistol grip. The light flux is directed in this case so that it completely illuminates the working area from below.

The convenience of a particular lighting scheme can be appreciated when choosing a tool.

• The most important selection criterion is the mass, balance of the instrument, and the convenience of its position in the palm of your hand. If work is expected at height, then more attention should be paid to lightweight compact models. And in t For frequent drilling operations, the weight of the tool even becomes a certain help in the work.

But in any case, when assessing the "throttle response" of a screwdriver in the store, the location of the center of gravity of the tool should be assessed - displacement forward or backward gives quick fatigue of the hand.

Experienced craftsmen advise to evaluate the place of transition from the handle to the trigger - it should be with a smooth transition at an obtuse angle. A rectangular or acute-angled transition will lead to quick fatigue of the middle finger during large-scale work, and can even cause the formation of calluses on it.

• The equipment of the delivery set must be assessed.

- The set must include a charger with a power cord. Modern "chargers" are a well-thought-out electronic circuit that will not allow the battery to overheat, and will automatically turn off when the upper charging limit is reached.

As noted above, you should not purchase a screwdriver with only one battery. - this is extremely inconvenient to work with.

- The kit may include a flashlight - as additional lighting during work or as a device for the necessary complete discharge nickel-cadmium batteries.

- Often, screwdrivers are equipped with special belts or even holster covers for the convenience of placing the tool on the master's belt when working at height.

- To included bits and drills m Many professionals are very skeptical, preferring to purchase the required types separately. However, leading manufacturers equip their kits with equipment enough high level... True, the specification is not always sufficient, and the need for an additional purchase often arises.

- Professional-grade screwdrivers can be additionally equipped with replaceable gear units. Example - model “ FESTOOL C15» .

In addition to the adapter for hexagonal bits, a keyless chuck can be installed on the tool. In addition, the kit includes a geared nozzle that allows drilling and tightening fasteners at an angle of 90 °. Yet it is a replaceable nozzle - this is an eccentric that transfers rotation to a drill or bits with an offset from the axis of the screwdriver. A very convenient function for working in a corner, where the body of a conventional tool does not allow for perpendicular force application.

True, the price for such kits is very high.

Brands you can trust

An important selection criterion should always be the manufacturing company and availability in a particular region. service this brand. For example, the dynamically developing European company KRÜGER.

Prices and range of KRÜGER screwdrivers

The German brand KRÜGER offers three models of screwdrivers: 12, 18 and 21 V. KRUGER tools are increased in power, equipped with various functions and are supplied with a rich package. The 12 and 18 V units work for drilling / tightening, the 21 V drill / driver is also equipped with an impact mode.

Kruger professional cordless screwdrivers (https://shurupovert.krugerpro.ru) show excellent technical characteristics. A large capacity lithium-ion battery is installed inside, which allows the tool to be used for a long time. The drill-screwdriver provides illumination of the working area, so it can be used in the dark or in places with poor lighting.

Using the tool, they not only drill holes, but also screw or unscrew the fasteners. The Kruger cordless drill comes complete with a set of 13 bits and 7 drills, as well as a charger that charges the screwdriver in just one hour. The reversing function allows you to quickly reach the stuck drill.

It is compact and light tool, which should be in the arsenal of every master. Depending on the modification, prices for Kruger screwdrivers vary in the range of 4000-8000 rubles.

• Without a doubt you can purchase Makita screwdrivers - this company has always been a leader in the production of power tools.

• Bosch offers a wide range of products, from inexpensive household tools to professional tools. Regardless of the class of screwdrivers, they all differ highest quality and reliability.
• The AEG tool is not cheap, but it fully justifies the money invested in it.

• DeWalt brand power tools are always distinguished by the most innovative developments in this field.

• Screwdrivers "Metabo", as a rule, are saturated with electronics, including regulating and torque value.

• Hilti brand tools offer high functionality, but still their price looks unreasonably high, despite the tempting manufacturer's warranty obligations.
• The affordable screwdrivers "Hitachi", "Sparky", "Skil" are in wide demand and good reviews are received.

• Among domestic manufacturers, it is quite possible to include Interskol, Caliber, Zubr in this row. Perhaps, in certain positions they lose to the novelties of the world's leading manufacturers, but in terms of reliability, service availability and price level, they are a very attractive choice.

But to acquire a "pig in a poke", under unknown delusion, most often made in China, is, of course, a "lottery". It is quite possible that such a screwdriver will serve a lot, and will fully cope with the tasks assigned to it. However, in the event of a failure, there is no need to count on any technical support or warranty. And big problems can arise with spare parts for self-repair.

And at the end of the publication - a very voluminous and informative video lecture on the choice of the optimal screwdriver.

Video: the right approach to choosing screwdriver

During repair and construction work, you cannot do without a good quality screwdriver. Such a tool is a must if you need to assemble furniture, unscrew an old screw, or hang a cornice or wooden shelf. Since there is a huge assortment of such devices on the modern market, it is quite difficult to stop a solution on one model or another. But how to choose a cordless screwdriver for home? What functional characteristics are of particular importance, and what may well be overlooked? How not to make a mistake when choosing? This is discussed in more detail in our publication.

The cordless home screwdriver is used equally by apartment owners and those who live in their own cottage. Basically, such a device is used for:

• Tightening and unscrewing fasteners (bolts, screws, screws, screws);
• Assembly work (to tighten anchors and dowels);
• To drill wood and metal surfaces;
• To cut threads in metal parts.

This device consists of several elements:

• An electric motor that rotates at a specific speed;
• A planetary gearbox, which is equipped with a clamping chuck and transfers the force to the spindle;
• A torque-regulating clutch attached to the gearbox;
• Clamping chuck for attaching attachments (bits) to the motor shaft.
• Electronic control system equipped with a special button for starting the device and a reverse switch;
• A battery that is used as a power source.

Varieties of screwdrivers

The name "screwdriver" is often used to refer to several types of tools, the functionality of which is very similar. The following main types of home screwdrivers can be distinguished:

• Electric wrenches;
• Electric screwdrivers;
• Drill drivers (the most common type of these devices)

Torque

This indicator determines the force with which the screwdriver resists the load or applies it to the screw being screwed. Typically, for domestic purposes, this device is equipped with a torque in the range of 10 to 15 Newton meters. Professional screwdrivers have a torque of up to 130 Newton meters. This functionality allows you to drill hard enough materials. The motor shaft of professional screwdrivers makes 1300 revolutions per minute, while for household data devices the indicator is 500 revolutions.
The range of standard sizes (diameter and length) of screws to be screwed in depends on what the torque is, as well as the hardness of the available working surfaces. An important difference between a screwdriver and other power tools is that you can adjust the torque due to the presence of a special limiter (a ring that is located after the chuck). Thanks to this functionality, it is possible to reduce to an absolute minimum the likelihood of bit wear, sinking too deep into the surface, as well as breakage of the slot at the self-tapping screw. The screwdriver protects the ratchet at the motor coupling against overloads. It is she who allows the twisting shaft to slip freely. Thanks to the set maximum torque, it is possible not to overload the engine and unscrew the tightest screw.

Good battery

When thinking about how to choose a screwdriver, be sure to carefully consider the battery. After all, it is not entirely comfortable to run to recharge such a device every half hour. In principle, it is not difficult to stop the decision on one option or another. It is enough to choose a more powerful analogue. Ideally, you can buy a spare battery as well. In some models, such a battery is included. The time required for recharging differs depending on the device. For example, for a professional screwdriver it is about an hour, for an amateur - about seven hours.

Varieties of batteries

As a rule, several types of batteries are used in screwdrivers:

• Li-ion;
• Nickel-cadmium;
• Nickel metal hydride.

The most popular at the moment are screwdrivers equipped with ecological Ni-MH batteries. In addition to environmental friendliness, they have several advantages: compact size, low weight, no memory effect. But there are also disadvantages: such batteries do not like electrical overloads and low temperatures. Besides, their cost is quite high. But they are more powerful and do not have as great a memory effect as nickel-cadmium. The number of recharges with stable capacity is 1500 times. Important: you cannot store these batteries in a discharged state, only in a charged state.
Another battery option is nickel-cadmium. They are more toxic. The number of recharges here is twice that of Ni-MH (nickel-metal hydride). This option is cheaper, it is not afraid of frost at all. But there are also disadvantages: batteries of this type suffer from strong self-discharge and memory effect. For storage, it is better to completely discharge them. Otherwise, there is a risk of getting a battery with a lower capacity.

Sometimes there are models with lithium-ion batteries. This type is sensitive to low temperatures. They are not powerful. The number of recharges is within 3000. There is no memory effect. The cost of such batteries is quite high, although this option is quite convenient to use. The service life and the permissible number of charging cycles in this case are at least two or three times higher than those of nickel-cadmium batteries. When deciding how to choose a good cordless screwdriver correctly, take the time to choose a battery. After all, just such a component of the device is almost half of its cost. Therefore, it is important to compare the following parameters:

• Battery capacity and voltage;
• Absence or presence of a memory effect;
• Absence or presence of self-discharge.

The battery is a removable element consisting of several power supplies concentrated in a common body. Such elements are fastened together using plates. At the output, the total voltage is summed up, making up 18, 24, 12, 10 volts. The capacity depends on the volume of the cell installed inside the battery. It is she who determines the operating time and the total number of recharges. The capacity decreases over time. The charge memory effect is the ability to lose capacity when the battery is not discharged and then fully charged. That is, you need to completely discharge it before charging. A charged battery lying idle loses its charge anyway. In this case, not only the output voltage of the battery is important, but also the ratio to the operating time of the amperage. This value is measured in amperes per hour. Higher rates provide a longer period of time for the battery to hold a charge.

How to choose a chuck for a screwdriver?

There are several types of chuck for screwdrivers: key and keyless. For the key, a special gear type key is used. Such a cartridge can have either one or two couplings. In the second case, we are talking about a quick-release mechanism. Keyless chucks can be two- or one-sleeve (this option is much easier to work with, because the entire operation can be performed with the movement of one hand). We recommend taking screwdrivers with a keyless chuck, they are much more convenient and easier to use.

Reverse

Reversing or reversing helps to pull a hopelessly stuck drill out of hard material or unscrew a tight screw. For convenience, the switch to the reverse mode is located directly with the start button of the device. He has two provisions. Thanks to the position between them - the device can be locked.

Design and comfort of use

If it is important for you to purchase a good device, you should not trust viewing beautiful photos, because comfort is difficult to determine visually. It is better to hold such a device in your hand, check if the buttons are tight, whether it is convenient to switch them.

Equipment

The complete set of the screwdriver may differ depending on this or that model. IN the best option - the presence of several nozzles for different screw heads. This way you can save both time and money on their subsequent purchase.

Key findings

For a household screwdriver, several parameters are important:

• Torque indicator from ten newton meters;
• Revolutions per minute 400-500;
• Two operating modes (drilling and twisting);
• Reverse function;
• Rechargeable device type;
• Nickel-metal hydride or nickel-cadmium battery type:
• Voltage ranging from 10 to 14.4V;
• It is better to opt for a higher ampere / hour value;
• The presence of a flashlight (as additional lighting when working or as a device to ensure the complete discharge of nickel-cadmium batteries);
• Special belts for comfortable placement of the device on the master's belt.