Cordless drill driver. Portable Power Tool Requirements Maximum RPM

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Screwing a screw is one of those tasks that seem to appear out of nowhere, but with enviable constancy. Fixing a warped closet door, hanging a mirror in the hallway, attaching a shelf in the bathroom are minor everyday problems that need to be solved daily. It is possible to tighten a bolt, screw or self-tapping screw with a screwdriver, but not always. Those who have tried it know that it is a thankless task, a long one, and the result is often zero. And you need to quickly and efficiently.

Buy electric for everyday domestic work homework is the best way. Not to mention that it is indispensable in the work of professionals. It is used at construction sites, during repairs and in furniture workshops. Using a screwdriver, they install drywall structures, install windows and doors, fix skirting boards and assemble furniture.

Choosing a screwdriver, focusing solely on its cost, is a gross mistake. They differ in power and various functions. In order not to make a mistake when choosing, you should carefully study it specifications before the purchase. The main ones are rotation speed, torque and battery type (in a cordless tool). But reading digital data is half the battle, you still need to be able to navigate what indicators are needed specifically for you and for the planned work.

1. Don't Overestimate: Buying a Household Screwdriver for Professional Work

The screwdriver can work from the mains or from the built-in battery. Not only the mobility of the tool, but also its power depends on the type of power supply. Small and handy cordless tool is the best helper for the DIYer. It has all the necessary functions, and it weighs very little, and the hands do not get tired. But the main disadvantage of a cordless screwdriver - low power - will play a cruel joke on those who plan to use it as a professional tool. That is, a lot and often. For the pros, you need a completely different power. The price of a professional is higher. Most often it is tied to an outlet, but it tolerates intense loads well.

2. Wrong battery selection

The most expensive part of the tool. More than half the price you pay for the battery. In order not to run every 20-30 minutes with a cordless screwdriver to the outlet for recharging, read the battery passport. We recommend that you carefully consider these parameters.

• Voltage (defines power)
• Capacity (affects run time)
• Memory and self-discharge effects (much better when none)

3. Buying low-capacity batteries for long-term work

Battery capacity directly affects the duration of work. The higher the capacity, the more time it can work without recharging. Capacity is measured in ampere-hours and depends on which element is installed inside the battery. Cadmium batteries have the smallest capacity, and lithium-ion batteries have the largest. Therefore, for long-term work, choose a lithium-based screwdriver. It costs 2-3 times more expensive, but gives a guarantee of work for several hours.

4. Long battery life

Charging times vary by model. A professional tool needs about an hour. Amateur - 5-7 hours. Buying a screwdriver that takes more time to charge than it works is a forgivable mistake for a home master. This tool is rarely used. And its long recharging does not bring inconvenience. For the "pros" - a long charge time nullifies all his work. The charging time depends on the specifications of the battery and charger.

5. Purchase a single speed screwdriver for drilling and screwing

A screwdriver is a versatile tool. Usually, in addition to "twist-unscrew", he is also able to drill. But not all models have this feature. Often the customer assumes that when purchasing a single speed tool, they will be performing screwdriving and drilling tasks. This is a common mistake. To work in screwing mode and in drilling mode, it must be equipped with a speed controller. Drilling is performed at a different speed than twisting. Work with different materials means different turns.

6. Buying a cordless screwdriver for very rare jobs

If you take a screwdriver once or twice a year, then it is better to buy an electric tool that works from an outlet. After all, each battery has its own shelf life. It needs to be charged and discharged, if not constantly, then often. Otherwise, it loses a lot of capacity. If the storage period is exceeded, the electrolyte stratifies, metal plates covered with salt inside.

7. Wrong choice of battery type

Having made a mistake with the choice of a battery and not knowing the features of its operation, you will eventually realize that it does not suit you at all. Therefore, keep in mind that three types of batteries are used in screwdrivers:

• nickel-cadmium (Ni-Cd). Inexpensive. But small and toxic. Suffer self-discharge and "memory effect". You can not store for a long time without charging. And the biggest disadvantage is that you can not charge an incompletely planted battery. That is, the possibility of recharging during a smoke break is excluded.
• nickel metal hydride (Ni-MH). Initially developed to replace nickel-cadmium batteries, but due to the same shortcomings, they could not take their rightful place in the assortment of batteries for power tools. More powerful, with the same dimensions, compared to Ni-Cd batteries. The charge cycle varies in the range of 200-300 recharges. The developers have eliminated the problem of the memory effect, so they can be recharged. The only negative is the high degree of self-discharge compared to other types of batteries.
• lithium-ion (Li-Ion). Most Popular. Large capacity and power. Do not lose capacity in the cold. The number of full recharges is 3000. You can charge at any time without waiting for complete discharge. There is no memory effect. Self-discharge too. But their price is much higher.

8. The most powerful is not always the best.

A powerful screwdriver is needed for long-term work with maximum load. If these are not planned, you should not choose a large power. Powerful has its drawbacks:

• He's heavy. It is inconvenient to work on weight, hands get tired.
• Large dimensions. You will not be able to work in hard-to-reach places.

For home work, it is better to take a screwdriver less powerful, compact, but with good torque.

9. Buying an impact driver instead of a hammer drill

If it has a shock mode, then this does not mean at all that it will be able to hammer a wall or a stone. A screwdriver is not a hammer drill. Run-out mode is used to drive bolts and screws more efficiently.

10. Wrong cartridge selection

There are two types of cartridges:

• Keyless (quick cartridge). Requires no clamping tools.
• Key. To clamp them, you need a special gear-type key.

Quick-release - much easier and more convenient. If you have to work with a frequent change of consumables (for example, a drill, a bit), then it is recommended to take a screwdriver with a quick-release chuck. The key cartridge greatly slows down the work.

11. One battery is good, but two is better

If there is another battery in the kit, this is a huge plus for your screwdriver. A spare battery gives you more options. While working on one battery, the second can be charged, and then vice versa. It turns out continuous work. But for household chores, one battery is enough, you should not overpay for an extended package. But for professional work - this is great option, in some cases, you can stock up on one more battery for future use.

12. Wrong choice of packaging

The cheapest packaging option is cardboard. But he won't last long. The packaging will break. Then there will be nowhere to store a screwdriver. For an amateur who bought an instrument for an apartment or house, this will not be a problem. But a professional master needs a case. You should choose it in a plastic case. It is convenient for storage and transportation. There are also thoughtful modular cases. They are attached to each other, can be transported on a wheelbarrow. These are optimal plastic suitcases for professionals like L-boxx or MetaLoc. Cases with such a system are often used by popular tool manufacturers: Metabo, Bosch.

13. Opt for smuggling

To buy a screwdriver from an incomprehensible manufacturer - to be left alone with a broken tool. No warranty, no service, no parts. Never be tempted by the too low price of China-under-China power tools. Please note that the "gray product" does not have an official guarantee, and reliable brands provide both a guarantee and service in service centers.

Many of their readers still remember those times when, to work with fasteners or threaded connections I had to use only screwdrivers and ordinary wrenches. It is clear that it is not even necessary 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, not enough overcoming the resistance of solid wood, not to mention the situation when it was necessary to "pierce" even the thinnest metal sheet. A few hours of such work - and the inevitable calluses on the hands, and the work progressed barely.

The situation has changed radically with the advent of screwdrivers. At first, they were referred to as a kind of instrumental "exotic", causing genuine envy. But very soon these useful tools appeared on the free market, “migrated” to the category of public ones, and today they are included in the mandatory “arsenal” of the vast majority of owners of houses or apartments. Those who are just now thinking about acquiring such an invaluable assistant should first understand the question of how to choose a screwdriver, that is, what to look for Special attention when evaluating a wide range of models.

The main types of screwdrivers

Under the general name "screwdriver", consumers often mean several types of such a tool 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 drill drivers. Some models can also be equipped with a shock function.

The most popular tools are those that work autonomously, from rechargeable batteries. However, it is quite possible to purchase a screwdriver that runs on a conventional 220 V / 50 Hz network. Tools with a cord for connecting to an outlet are commonly called “network”.

It is necessary to get to know the main types better - 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.

Despite the fact that in terms of their main performance indicators and overall functionality, cordless screwdrivers are to some extent inferior to standard ones drill drivers, they have their own specific advantages, which make these instruments widely popular among both professional craftsmen and amateurs. These invaluable "advantages" include a small mass, compact layout of the device, high ergonomics. This allows you to use cordless screwdrivers in conditions where the use of a larger tool is either more inconvenient or even simply impossible.

Such a tool becomes indispensable for production lines for the assembly of small household equipment, computer and office equipment, they are widely used by craftsmen in the production process or final assembly. Due to their compactness, ergonomics and low weight, these screwdrivers do not cause rapid hand fatigue, and therefore are very convenient for working at heights, including, for example, when installing false ceilings.

Cordless screwdrivers are different in their layout. Many models have a cylindrical body, which, however, is equipped with a swivel that allows you to fold if necessary, to concentrate the pressing force of the hand.

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

In addition, very easy-to-use models are available, in which the swivel 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 not possible 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 of 3 to 9 V. Screwdrivers do not have high rotation speeds - usually 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 more advanced models equipped with a two-speed switch, and allowing you to perform drilling work with plastic and wood - their rotational speed can reach up to 600 rpm.

Almost all cordless screwdrivers are equipped with a ¼" hex bit adapter. Usually bits under Various types fasteners, as well as drills large diameter with the same hex shank are included with the screwdriver itself.

Unlike larger tools, electric screwdrivers are often equipped with a non-removable battery located in the product body. For charging, a special power adapter is used that plugs into a power outlet.

What is the result? If the owner has a good drill in his tool kit, 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 the type of tool that very similar to a screwdriver, and even in certain circumstances it can be used as it, but still has features that are directly related to its intended 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 using wrenches to perform monotonous operations means drastically reducing the productivity of his work. A classic example is an assembly production put on stream or, which is closer to private practice, car repair or tire shops. In addition, in particular, when repairing machines, it is very often necessary to deal with old, “soured” nodes, which are very difficult to unscrew manually, even after processing with a special compound.

The way out is to use an impact wrench. Its design is such that, in addition to the usual rotational movement, impulse actions with a certain frequency are also transmitted to the working part of the spindle by a special mechanism. In a word, these are a kind of “micro-shocks”, capable of moving and unscrewing even very rusted nuts or bolts, without violating the integrity of the faces of their head.

Most nutrunners have the usual "pistol" design, but can be additionally equipped with a removable side handle to concentrate the clamping force when breaking the connection. 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 special drive power - usually it ranges from 350 W for the smallest tools and even up to 1300 W for professional-grade devices. The rotation speed does not play a decisive role here, and it is usually small. 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, wrenches are very similar to screwdrivers, but they are distinguished by a feature - the absence of a maximum torque adjustment ring (“ratchet”). The working end of the spindle is also different - most often there is an adapter-square for socket heads. The dimensions of the square for models of different power can vary - ½ (most often for household models), ¾ or even 1 inch (for a professional powerful tool), which means that sets of heads should be purchased accordingly. Although, there are special adapters for this case.

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 inch hexagons - bit shanks or drills.

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

In a word, impact wrench, if the specifics of the work of the mater involves its frequent use, it will be a good addition to the screwdriver, but it is unlikely that it will be able to completely replace it in the householder's arsenal.

By the way, many well-known manufacturers release tool kits,which are included and drill driver, and an impact wrench that run on a single set of batteries. Here it's a really versatile set. True, its cost is quite high, and such a purchase should be really justified.

Drills

This is the most common and most frequently purchased variety of such tools, which has increased versatility.

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

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

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

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

4 - key (trigger) start. Moving the trigger at the same time smoothly adjusts the speed of rotation of the screwdriver's spindle. Usually the trigger is also covered with a pad of rubber or soft plastic.

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

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

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

8 - clamping jaws of the cartridge.

9 - an indispensable element of any screwdriver - a mechanism for limiting the torque transmitted to the chuck. It is usually 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. A 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 icon.

10 – modern models screwdriver in more often they are equipped with an LED workspace illumination system. Location LEDs may be different.

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

What to look for when choosing screwdriver

Deciding to purchase a particular model drill driver, the future owner of the instrument must clearly understand, for what goals it is necessary what kind operations are planned to be performed by them and with which exploit intensity. It is these preliminary "bastings" that will become the base points when evaluating the characteristics of the devices offered for sale.

Type of batteries and their characteristics

It is advisable to start the consideration with the "energy" of the screwdriver. No matter how wonderful the tool itself is, its performance directly depends on batteries, the cost of which, by the way, is always more than half the price of the entire kit. Surely, many have had to deal with a situation where the screwdriver itself is still quite functional, but the way out of troy power supply 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 encourage users to purchase a new set.

The main characteristics of batteries for screwdrivers are voltage and capacity.

• From voltage directly the power of the electric drive and, accordingly, the maximum torque, which determines functionality tool. So, on sale most often there are screwdrivers with batteries with a voltage of 9.6; 12; 14.4 or 18 V. This, however, is not the limit - powerful professional tools have batteries of 20 or even more volts (up to 36). 9 volts still looks not enough even for a household tool. The best solution for a screwdriver purchased for home use is likely to be the "golden mean" - with 14.4 V batteries.

By the way, you can find almost the same ones 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 meet both one and the other designation). Usually this indicator is indicated on the marking made on the battery case, next to the voltage.

In fact, battery capacity is a value that shows how long the tool can operate 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 put the elements on recharging.

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

The performance of batteries is directly dependent on their types. This issue requires closer consideration.

• Nickel-cadmium batteries (Ni-Cd )

Due to the low price, such batteries remain the leaders in the 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 operating and storage temperatures.
• The only ones that exist, they are not afraid of an absolutely complete discharge. Nickel Cadmium it is quite possible to store the battery in a discharged form - and after that it will fully recover after proper charging.

They have a lot of disadvantages:

• Inability to achieve high specific capacitance. An indicator of 2 Ah, at best, will already be the limit.
• A rather short overall "life" - even high-quality Ni-Cd-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 “sat down” from storage and does not cope with its task.
• The main "ailment" 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 level of charge is still perceived by the device as the minimum value. Thus, the capacity of a fully charged battery spontaneously decreases by the value of the previously undeveloped 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 with a screwdriver), and only then insert it into the charger. This can be extremely inconvenient, especially in situations where it seems that the power of the tool is already beginning to be lacking, and “hands are reaching out themselves” to put the battery on charge.
• Improper disposal of used nickel-cadmium batteries can harm the environment.

However , nickel-cadmium Batteries are considered true "workhorses", and are most often installed on household-class models. In such operating conditions, their qualities will be quite enough.

• Nickel metal hydride batteries (Ni-MN )

Nickel metal hydride 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 good step is still impossible.

Advantages of such batteries:

• Their production and disposal are environmentally friendly.
• High charge capacity, which can quite reach 3Ah. And this, coupled with a more compact size of the battery itself. Accordingly, the specific power of the power supply is higher.
• The negative effect of memory is no longer so significant, oneako, it was not possible to completely get rid of it.

Disadvantages of such batteries:

• Their price is significantly higher than nickel-cadmium.
• Low duration of "active life" - the number of recharge cycles rarely exceeds 500.
• Such batteries are characterized by a high level of self-discharge - the drop can reach up to 10% on the first day of storage after a full charge.
• The performance of batteries is sharply reduced when working in conditions of negative temperatures.
• These batteries must not be stored in a fully discharged state.

In short, the high price of such batteries looks unjustified. It is better to purchase or a cheaper running option - nickel-cadmium, or don’t be stingy anymore and choose a screwdriver with lithium-ion batteries.

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

• Li-ion rechargeable batteries (Li—ion)

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

The advantages of such batteries are as follows:

• The memory effect is practically absent, that is, you can recharge the battery at any degree of its discharge.
• Among all other batteries, lithium-ion batteries have the highest charge capacity and power density.
• Charging speed is the fastest.
• But the effect of self-discharge is extremely weak. It is considered normal that for a year of storage under normal conditions, a high-quality lithium battery can lose no more than 20% of its charge.
• The term of active life, the allowable number of charging cycles of such a battery is three times, or even more, exceeds similar indicators nickel-cadmium.

There are also several disadvantages:

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

When choosing desired 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 standing on a screwdriver, the second one is being charged. True, when using Ni-Cd batteries, you should always keep in mind the need to fully discharge them so as not to cause a “memory effect”.

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

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

The performance of the tool does not suffer from this, but the amenities, 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. In most models of the low price range, the already old and proven scheme with a brush collector is used. Such engines are quite reliable, but still not without drawbacks. And the main one is significant friction forces at the place where the brushes fit to the collector lamellas. Naturally, this is accompanied by a significant release of thermal energy, and the drive heats up quite quickly. In addition, sparking of the brushes on the collector is not excluded, especially if you have to work in conditions high humidity air.

All these shortcomings are deprived of a brushless motor with electronic control. The absence of an additional friction area leads to a sharp increase in tool performance. So. tests carried out on similar models with batteries of exactly the same characteristics showed that a screwdriver with a brushless motor did almost three times more work than with a commutator one.

Some manufacturers (for example, DeWalt) decided to get rid of the engine housing - all its components are located directly in the housing of the screwdriver itself. And this is not a trifle at all - it turned out to be a significant gain in the total mass of the tool, which has become much more convenient to work with.

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

• When choosing, be sure to clarify what materials the screwdriver gearbox is made of. This mechanical assembly is subjected to the greatest loads, and its quality will determine the functionality and overall life of the entire tool.

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

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

Rotation speed adjustment from zero to the maximum is made by changing the force of pressing the trigger (key). For a more comfortable performance of basic operations, you should choose a screwdriver, which has the ability to switch the gearbox to high and low speeds. Usually the switch is located on top of the housing.

• Maximum torque - important characteristic, from which the functionality of the screwdriver is envied.

So, to work only with small fasteners, 10 Nm is enough, but it will be more like 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 large-diameter crowns or metal, choose screws rt with a torque of 36 Nm or more.

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

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

If the set force is exceeded, the ratchet or slip clutch is activated, and the excessive torque is not transmitted to the fastener.

The numbers on the scale show only the serial number of a particular switch position as the tightening torque increases, but are in no way connected (as some inexperienced users mistakenly believe) with the diameters of the fasteners. The drill symbol indicates the maximum torque required to drill.

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

Cartridge type

Most modern screwdrivers are equipped with quick-release chucks, making it easy to change bits or drills.

Keyless chucks can be single or double sleeve.

In a two-sleeve chuck, when installing and removing a 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 sleeve - the whole operation is performed with the movement of one hand. True, at the same time, the screwdriver itself must be equipped with a spindle lock function. Such blocking can be automatic, triggered when the rotation stops, or forced (there is a special button).

By the way, when choosing a screwdriver, be sure to clarify whether the tool has the option of forced spindle braking - when the trigger is released, the rotation should immediately stop. 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 turning off the power, you should not purchase it, as it will cause a lot of inconvenience in work.

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

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 cartridge at all - with an adapter for a ¼ inch hexagon.

In this case, if you need to make any small drilling operations, 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 features.

• In addition to rotational, it can also be provided for impact force on the tool chuck. This allows holes to be drilled in some building materials. Such screwdrivers have a switch between normal and impact modes. It can be located both on the torque switching ring, and taken out separately.

Many models of hammer drills come with an additional detachable side handle to accentuate forward force when drilling.

By purchasing a similar screw rt, it should still be quite realistic to imagine that he can cope with 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, it is better to have a perforator for such operations.

• A great help in the work can be the presence of a pulsed mode of operation of the tool - by analogy with impact wrenches. This allows you to deal with soured threaded connections or accurately mark the start of the drill in dense material.

The inclusion of the pulse mode can be on the torque adjustment ring, or it can be performed in the form of a separate button that is pressed as needed.

• An additional convenience when working will be the presence of a built-in backlight. The LED "flashlight" can be located coaxially with the body, under the cartridge. However, as practice shows, this is not always convenient - the cartridge itself can obscure the area of ​​\u200b\u200bwork.

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

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

• The most important selection criterion is the weight, balance of the tool, the convenience of its location in the palm of your hand. If work at height is expected, 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 “acceleration” of a screwdriver in a store, one should evaluate the location of the center of gravity of the tool - moving forward or backward gives a 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 under obtuse angle. A right-angled or acute-angled transition will cause the middle finger to quickly fatigue during large-scale work, and may even cause the formation of calluses on it.

• Be sure to evaluate the equipment of the delivery set.

- The kit includes a charger with a power cord. Modern " chargers"- This is 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 buy a screwdriver, equipped with only one battery. - it is extremely inconvenient to work.

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

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

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

True, the price of such kits is very high.

Brands you can trust

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

Prices and the lineup KRÜGER screwdrivers

The German brand KRÜGER offers three models of screwdrivers: 12, 18 and 21 V. KRUGER brand tools are increased in power, equipped with various functions and come with a rich package. The 12V and 18V units work for drilling/tightening, the 21V drill/driver also has 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 you to use the tool for a long time. The drill-screwdriver provides illumination of the working area, so it can be used at night or in places with poor lighting.

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

This is a compact and lightweight tool that should be in the arsenal of every master. Depending on the modification, the prices for Kruger screwdrivers vary in the range of 4000-8000 rubles.

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

• A wide range of models, from inexpensive household to professional tools, is offered by Bosch. Regardless of the class of screwdrivers , they are all of the highest quality and reliability .
• The AEG tool cannot be called cheap, but it fully justifies the money invested in it.

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

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

• Hilti brand tools are a high functionality, but still their price looks unreasonably high, despite the tempting manufacturer's warranty.
• are in great demand and good feedback get affordable Hitachi, Sparky, Skil screwdrivers.

• Among domestic manufacturers, it is quite possible to put Interskol, Caliber, Zubr in this series. 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 an unknown delirium, most often made in China, is, of course, a “lottery”. It is quite possible that such a screwdriver will last a long time, and will fully cope with the tasks assigned to it. However, in the event of a failure, it is not necessary to rely on any technical support or warranty. And with spare parts for self-repair, big problems can arise.

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

Video: the right approach to choosing screwdriver

December 14, 2016 No comments

The screwdriver has become today one of the most popular tools among professionals and home craftsmen. It is useful when assembling furniture, installing drywall and plywood structures, laying roofs from metal tiles and other works. Let's talk about this tool in more detail.

A screwdriver is a hand-held 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: an engine located in the body drives a nozzle through a gearbox, which does the work. The difference lies in the energy source (the screwdriver runs on direct current) and the lower speed transmitted to the nozzle. The latter is due to the fact that the screwdriver was originally adapted to work with fasteners, at which high speeds are not needed. True, modern screwdrivers and in this parameter differ less and less from drills. It is not for nothing that most manufacturers position their tools as multifunctional, calling them drills-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 body from the bottom of the handle and 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 fastening nozzles (bits and drills) and transferring rotational motion to them. The most common keyless chuck, which allows you to easily clamp the nozzle without the use of an additional tool.

Manufacturers also produce specialized power tools in the screwdriver line - for example, electric screwdrivers that are popular today, which are small in size and low in power. They will do a great job with small repairs in the apartment, in the country. Nutrunners, unlike them, have great power, they will help to unscrew, say, a rusty bolt when removing a wheel from a car.

Torque setting clutch and speed switch.

By 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 cuff for setting the operating mode of a powerful screwdriver (twisting, drilling, drilling with impact).

An electric screwdriver is great for small repairs. The impact wrench has increased power and can become an assistant during construction.

Main characteristics of the tool

When choosing a screwdriver, first of all, you need to pay attention to two parameters - torque and rotational speed. The torque value shows how much force is applied to the screw (drill) being screwed during operation. From this will depend, for example, a hole
What diameter can this screwdriver drill? In household tools, the torque is 10-16 N m.

For professional models, this figure can reach up to 130 N m. The rotation speed for 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 is most often three-speed. In addition, the rotational speed is adjustable within one speed by pressing the power button.

Batteries serve as a power source for screwdrivers. 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, although the dependence here is not direct.

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

Nickel-cadmium (Ni-Cd) batteries

Recharging resource - within 1,000 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, they 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. Bits can be clamped directly into the chuck or fitted into an adapter clamped into the chuck. The working part of the bit is a kind of screwdriver of such a configuration, which depends on which fastener this nozzle is used to work with.

Getting started, you need to choose a bit that matches the head of the fastener. The most commonly used are cross bits, which come in PH and PZ standards. PH is short 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 PZ designation is derived from Pozidrive, these are also bits with a cross-shaped working part. In addition to the main large ribs, they have A additional smaller diagonal ribs. Thanks to them, the area of ​​adhesion 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 repair household appliances and cars are indispensable without T-bits (from Torx Hole), with which you can unscrew and tighten the screws with a star hole on the cap. Flat, or slotted, bits are suitable for working with fasteners in soft material, at not too high a load. Such bits are marked SL (from Slot).

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

Screwdriver bit sets often include drill bits with a hex shank. The angled nozzle will help when working in hard-to-reach places. Drill chucks for drills with cylindrical shank are often used as nozzles for screwdrivers.

Additional screwdriver options

Screwdriver options from different manufacturers can vary 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 a particular option.

• Illumination - one or more LEDs located radially in front of the housing. Makes it easier to work in poorly lit areas.
• Removable handle for comfortable holding of the tool while drilling. It will help when working with a powerful tool, using large diameter drills and drilling with impact.
• The depth gauge is useful for serial drilling of identical holes.
• The clothespin makes it easier to fix several nozzles on the body or the tool itself on the master's clothes when moving around the construction site (convenient when working at heights).

Models from different manufacturers

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

The cordless drill/driver is designed for drilling holes in various materials, as well as screwing and unscrewing screws and screws during assembly work. Thanks to the ergonomic handle with a 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 belongs to a new generation of cordless power tools with new Li-lon batteries. New design engine provides economical energy consumption, which significantly increases the operating time. The ergonomic handle and body are rubberized to the maximum, which contributes to the reliable holding of the tool. The model is equipped with a holster for carrying on a belt. The kit includes an extra battery, charger and flashlight.

Please check the portable power tool requirements before purchasing. They are regulated state standards and specifications on electrical safety.

You can get acquainted with them, for example, on the Energokontakt website.

First of all, we list what applies to portable power tools. These are electric soldering irons, electric drills, screwdrivers, wrenches, furrow cutters, electric hammers, grinders, portable electric heaters for technological needs, step-down transformers for powering power tools, local lighting fixtures, portable electrical panels and other current collectors.

Classes

Portable power tools are divided into classes.

The zero class includes a power tool with working insulation, without grounding elements, not belonging to the second and third classes.

The first class power tool has a working insulation and an element for grounding. Its wire leading to the power source must be equipped with a grounding conductor and a plug with a grounding contact.

Class 2 power tools have double or reinforced insulation, but no grounding elements.

The power tool of the third class is designed to operate at extra low voltage (not more than 42 volts) and does not have any electrical circuits operating at a different voltage.

Voltage for tools of the first and second classes - no more than 220 volts at direct current, 380 volts at alternating current.

room

The voltage of the tool must not exceed 380/220 volts when working in rooms without increased danger and 36 volts in other rooms or outside them.

In rooms with increased danger, there is one of the following factors: high dampness (relative humidity more than 75%); temperature above 35ºС; conductive floors; conductive dust; the possibility of simultaneous contact with the metal structures of the building that are connected to the ground, or with technological equipment - on the one hand, and with the metal case of electrical equipment - on the other.

Particularly dangerous are rooms with a relative humidity of about 100%; with a chemically active or organic medium; containing two or more risk factors.

The main thing general requirement for individual users - to work from the mains only if the power tool has a non-removable flexible cord with a plug. The cord must be protected from damage and contact with damp, hot and oily surfaces.

When the plug is turned on, its design must ensure the early closing of the grounding contact, and when turned off, the subsequent opening. It also needs to be protected from moisture. The power tool must be quickly connected to the network and disconnected from it (but not spontaneously).

Faults

And super important! If any, even a minor malfunction is detected, work must be stopped immediately!

Typical malfunctions of a portable power tool include: damage to the plug or cord; fuzzy operation of the switch; leakage of lubricant from the gearbox; sparking of the collector brushes with the appearance of a circular fire on the surface; the appearance of smoke, the smell of burnt insulation, hanging noise, knocking or vibration.

To ensure safe operation, it is very important that the body of the power tool is grounded.

Man

Power tools may only be operated by persons specially trained in safe handling. In the event of a malfunction, you cannot repair the tool or its cord and plug yourself - such repairs are usually not of high quality.

When working with power tools, depending on their type, you need to use tools personal protection, which include a cotton suit or dressing gown, dielectric gloves, galoshes, rubber and rugs, etc. In especially dangerous rooms, the use of personal protective equipment is mandatory!

Before starting work, it is necessary to carefully inspect the power tool for proper grounding and insulation of wires, the absence of bare live parts and defects. Defective power tools must not be used!

At the end of work, do not forget to unplug the power tool from the mains.

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