What do the numbers on the screwdriver mean. How to use a screwdriver ratchet, why is it needed at all? Eliminate errors during selection
Based on the types and technical properties necessary for many species construction works tool. Having basic information about what screwdrivers are for and how they are used in everyday life or in professional activity, you will not go wrong with your choice when buying a tool.
Where is a screwdriver used?
A screwdriver will perfectly replace a drill, drill through metal and even concrete. The moment will come when the screwdriver will almost replace the screwdrivers.
Screwdrivers are needed to:
. It is easy to tighten or unscrew various fasteners: self-tapping screws, screws, bolts.
. Drill holes in the most various materials. Screwdrivers can make holes in metal, wood, drywall, brick.
But the people found other uses for screwdrivers, sometimes completely unexpected. For example, with this tool you can perfectly mix mortars and paints, as well as drill holes in the ice if you went ice fishing.
What types of screwdrivers are on the tool market
There are enough classifications of screwdrivers. Manufacturers produce household and professional tools, which, in turn, may differ in batteries, in particular, in their power, in the diameter of the cartridge, in the materials from which the gears of the gearbox are made. There are screwdrivers additional functions. It is clear that the price various kinds screwdrivers are also different. The price also depends on the brand.
Consider how screwdrivers differ in terms of batteries. Devices are divided into two large groups: cordless screwdrivers and electric.
Li-Ion batteries
Li-Ion batteries are extremely common and popular today. They are used in many tools, portable devices, etc. What explains such a demand for these batteries? Their advantages include:
. Three thousand battery charge cycles.
. Batteries are very lightweight and very light.
. The battery charges very quickly.
. The battery does not have a memory effect on the charge.
But the modern Li-Ion battery also has negative qualities. For example, such a battery only works for three years, which means that it must be used to the maximum during this period, otherwise it will be a pity for the money spent. Li-Ion batteries are quite expensive. Li-Ion batteries are afraid of frost, so if frost resistance is important, then it is better to choose Ni-MH batteries.
Conclusion:
. Data rechargeable batteries you need to buy if you have a constant, and not one-time work with a screwdriver.
. Fully charging and discharging is not recommended for Li-Ion batteries in order for the battery to last as long as possible (discharge - at least 15%, charge - no more than 90%).
. To calibrate the battery, it is enough to perform three charge-discharge cycles (the cycles are performed in a row).
Ni-Cd rechargeable batteries
These batteries have been used for a long time in screwdrivers and other tools. The number of charge-discharge cycles is one and a half thousand. Such rechargeable batteries serve longer than Li-Ion - five years. The use of Ni-Cd batteries allows you to use the tool when low temperatures(at frosts no more than 15 degrees). The popularity of these devices is also facilitated by the fact that their cost is the lowest for batteries.
The disadvantages of Ni-Cd batteries include:
. Charging the battery lasts quite a long time, at least an hour, or even more.
. The battery has a memory-to-charge effect.
. The Ni-Cd rechargeable battery has a significant weight.
Conclusion:
. Insofar as Ni-Cd batteries Due to the memory effect of charging, batteries need to be fully charged and discharged to allow them to last a long time.
. Full charging is carried out using a conventional charger.
. A full discharge can be performed using a flashlight, which is often included in many screwdriver kits.
Voltage and capacity in batteries
Batteries differ from each other in such important parameters as capacity and voltage.
The unit of capacitance is ampere times hour (Ah). The charge of the battery directly depends on its capacity. Accordingly, with an increase in capacity, the duration of work that can be performed without recharging the battery increases.
The battery voltage, the unit of which is Volt (V), determines the power of a screwdriver or any other battery-type tool. In the language of professionals, this means that it depends on the voltage, what indicators will have both soft and hard torques of a screwdriver.
Mains (electric) screwdrivers
These screwdrivers are connected to the mains and are similar to electric drills. The main difference between such a screwdriver and a drill is that it can adjust the torque.
Screwdrivers¸ that are powered by the mains are great for work at home, which is performed from time to time, and for professional builders. The screwdriver does not need to be charged, it works as needed from the network, and this is its undoubted advantage. But there is also back side network tools, created precisely by the presence electrical network: firstly, you need electricity to work, and secondly, the wire of the tool often interferes, limiting mobility and getting under your feet.
About the chuck and gearbox in a screwdriver
The screwdriver can have either a three-jaw keyless chuck (with a tool clamping range of 1/2-13 millimeters), or a chuck that has a hex socket with a 1/4 inch shank. The larger size of the keyless chuck makes the screwdriver more versatile.
The tooling changes very quickly with a hex chuck, which is a great convenience if changes are made frequently. Often, in the presence of such a cartridge, drills with a hex shank are used. A combination of a conventional chuck and a hex shank is possible.
The gearbox is needed to transmit the momentum of rotation of the engine to the cartridge. The torque parameters depend on the gearbox. Reducer gears are either made of metal (usually steel) or plastic. Professional screwdrivers use only metal gears.
Power
Important technical specification screwdriver is its power, depending on the torque (soft and hard). Torques are measured in Nm (Newtonometers). The tool is more powerful if the number of torque is greater, that is, the screwdriver can drive thicker and longer self-tapping screws or drills into hard or viscous material.
. Soft torque characterizes the maximum twisting or loosening of the screwdriver. The soft torque range is 0-350 rpm.
. An indicator of the maximum effort when drilling is a hard torque. Its range is 0-1000 (maybe much more than 1000) revolutions per minute.
The performance of a screwdriver depends on the maximum torque settings. For example, with a torque of 25-30 Nm, it is usually easy to screw a self-tapping screw up to 70 millimeters long into a tree. For self-tapping screws up to 100 millimeters in length, a torque of more than 40 Nm is required (for wood). If the screws are even longer, you first need to, as a rule, drill a hole for it in the material.
Additional features found in screwdrivers
Many brands produce screwdrivers equipped with additional features. Many arguments can be made in favor of both specialized and multifunction tools but usually well-known manufacturers Screwdrivers are equipped with a number of additions:
. The impact mechanism is useful if you have to work with socket heads, and also, if necessary, make a hole in brick or concrete with a drill.
. The pulsed mode (temporary torque amplification mode) will make it easier to drown the fasteners into the material, easily unscrew the stuck self-tapping screw or drill if the puncher cannot cope. In addition, the pulse mode is very important if you can not rest against the tight pressing of the screwdriver.
. The possibility of backlighting, which is a relevant addition when working in places where there is poor lighting or none at all. The backlight is usually placed above the battery.
. Battery charge indicators and automatons that turn off charging.
Clearly the more additional features, the more expensive the screwdriver. As you can see, there is no universal tool suitable for any task. And you should choose a screwdriver, always assuming the purposes for which it will be used.
What should be guided by when choosing a tool for work at home or in the country
Usually for home or dacha works enough network model. Its weight is small, there is no particular need for mobility. When choosing a battery version, it is better to buy Ni-Cd or Ni-Mh if frequent work is not expected. If you have to work often, a modern Li-Ion battery will justify itself.
As for torque, 25-35 Nm is quite normal for home use. A more powerful screwdriver can also be taken if your financial capabilities allow.
A battery with a capacity of one and a half to two amperes per hour with occasional use at home or in the country is quite suitable for you.
What should be guided by choosing a tool for professional use
If you have to use a screwdriver in hard-to-reach places, it is better to purchase compact model. With long and frequent continuous use of the tool, it is logical to stop at the Li-Ion battery. The maximum torque of the screwdriver must not be lower than 40 Nm. But of course, the torque can be more, depending on the type of material you will be working with (of course, drywall and brick require different torques).
Why choose Li-Ion batteries? They ensure the continuity of the workflow due to the fact that they can be quickly charged. In addition, their weight is quite small, which becomes a very important factor with prolonged use (the arm gets tired less).
To select additional features, you need to clearly understand the nature future work. If you have a hammer drill as well as a drill, you are unlikely to need all the possible additions that modern screwdrivers are equipped with. Therefore, there is no need to overpay for multifunctionality if it is not needed for the application.
There are many models of screwdrivers on the market now, so you can always find a tool that is suitable for solving your particular tasks. We hope that the article you read will help you as much as possible. good choice screwdriver.
Very often on the forums, people wonder what power they should choose a screwdriver to calmly wrap self-tapping screws or screws of such and such a diameter and length? Or, in other words, what torque should a screwdriver have in Nm for certain tasks?
People get different answers to these questions. Most often, there are offers from "all-knowing specialists" to buy expensive semi-professional 18-volt models. Like, they are definitely on the shoulder. But is it worth paying twice as much if it suddenly turns out that the younger 10-14 volt models are also good? And if there is a difference, what is it?
We will try to briefly talk about the theory and move on to practice.
Theory
Looking at the table, you might think that any of the commercially available screwdrivers is suitable for 5x90 screws. But this is not entirely true, which is discussed in the practical part of the material.
Let's summarize the theory:
- we do not know from which "ceiling" the figures for the torque characteristics of screwdrivers indicated by the manufacturer are taken;
- also Captain Evidence suggests that the material used has a noticeable effect on the whole process, as well as the parameters of the screws.
Practice
For practical exercises, we took three different screwdrivers and two different types screws / self-tapping screws and we will twist them into a dry pine beam, simultaneously fixing the success of the operation and the time spent.
Here are the names of the models of screwdrivers and their brief technical characteristics:
Two "old men" (Bosch and DeFort) were not accidental here. These few powerful models they will immediately make it clear how true all of the above theory was, and whether absolutely any screwdriver is enough to successfully work with 5x90 mm self-tapping screws and the like. And the average Hitachi will simply complete the picture and play the role of a modern instrument.
With regard to the screws, we did not waste time on trifles and took a thin black 4.8 x 127 mm for testing and, for completeness, a powerful white 6 x 150 mm. To screw the latter into a pine beam, a maximum torque of about 11 Nm is presumably required.
So, as a result, we suggest you watch a short video in which we captured the whole process.
A thin self-tapping screw (4.8 x 127 mm) turned out to be a feasible task for all screwdrivers without exception, although it was clear that Bosch did not come so easily. The time spent by the screwdrivers was: 5.3 seconds for DeFort, 7 seconds for Bosch and 2.9 seconds for Hitachi. We did not set the task of an exact comparison of time and repeatability, only the final result was important to us. Therefore, we made only one take for each of the models.
The white "strong man" turned out to be too tough for everyone. As in the previous case, DeFort started very cheerfully, but he did not submit to the last centimeter.
Bosch, although it solved the task, but the smell of burnt windings made it clear that such loads are categorically contraindicated for this tool.
Well, for the powerful Hitachi, both self-tapping screws are like toys. Here's what the stopwatch showed: 13.3 seconds for DeFort (did not turn 1 cm), 20.7 seconds for Bosch and 4.3 seconds for Hitachi. In addition, we note that Hitachi worked during the test at the second speed, where the torque is at least a third lower than the maximum stated in the specifications.
We have one more thing for the practical part important note A: Our test included older screwdrivers (Hitachi not included) that don't have an overload protection system. Majority modern models they have such a system, therefore they will not let them mock the tool like that, as can be seen in the video with the Bosch screwdriver. This also means that the protection system will not allow such a screw to be completely screwed the first time. You will have to turn on the tool several more times until the next protection is triggered (usually 1-2 seconds), until the screw is tightened. But in order not to mock the tool like that, of course, you need to buy a screwdriver with a certain power reserve!
The scope of the screwdriver is very large, because it is universal tool. For example, disassemble the lock, attach a baseboard or bookshelf, drill a hole in wood or stone. A similar tool to a screwdriver is a drill. Due to the lack of reverse and speed control, a screwdriver is chosen. Let's talk about how to choose the tool that best meets your requirements.
When choosing, you should pay attention to only three parameters: manufacturer, power and type of battery. Because the device and the principle of operation of a screwdriver are the same for everyone.
Manufacturer's choice
It makes no sense to focus on a specific manufacturer. All manufacturers have a quality control system. Major manufacturers they spend a lot of money on advertising, their screwdrivers are of high quality, but sometimes unreasonably more expensive than analogues. Small manufacturers spend on advertising less money but the quality doesn't suffer. The conclusion is that it is not necessary to chase after a famous brand if the budget is running out.
We distinguish three types of cordless screwdrivers: Lithium-Ion (Li-Ion), Nickel-metal hydride (Ni-Mh), Nickel-cadmium (Ni-Cd) and network, we will analyze each in more detail below.
Power
Torque - the force applied by a screwdriver to twist / drill (measured in Newton meters, further N * m). This parameter determines the length and thickness of the screw that can be driven, and when drilling, the maximum hole diameter in hard materials. In domestic use, use a screwdriver with a torque of 10-20 N * m, for more serious work from 25 to 50 N*m. The maximum torque in such tools can reach 130 N * m. Screwdriver speed - you are going to drill, you should look at the speed parameter from 1200 to 1500 rpm. For tightening screws, 400-550 rpm is required. A screwdriver can have two speeds, this choice is universal.Battery type
Li-Ion batteries.
The most commonly used battery type today is Lithium-Ion (Li-Ion). It has three thousand charge-discharge cycles.
Pros:
- Light weight;
- fast charging;
- High capacity;
- Not affected by charge memory.
- The most high price from all types;
- Dislikes negative temperatures.
If we talk about a 10.8 V battery, it uses three of these cells. At 14.4 - four. At five. If we are talking about home use, then in no case store long time in a discharged state this battery. Otherwise, you will have to buy a new one, and they are not cheap.
Voltage(unit Volt V). This indicator affects the power that can be obtained from a screwdriver. in plain language, voltage directly affects the maximum performance. In practice, this indicator is not so important, for example, if you take two screwdrivers that give out 25 N m, one is powered by a 14.4 V battery, and the other from 18 V, then you will not see much difference in work, and the latter will work not much longer .
If you do not need a cordless screwdriver, and the budget is very limited, a corded one will suit you. Their choice consists of determining the torque. 
Corded screwdriver useful for both occasional work at home and for professional use in repair and construction. But here, there are both pluses and minuses.
The advantages include:
- Does not require charging;
- Power is always at the same level and does not depend on the battery.
- Dangling wires underfoot when other devices are connected;
- Attachment to the place of the outlet.
- One of the features of the screwdriver is cartridge type. There are both quick-clamping (single-sleeve and double-sleeve), and cam. Clamping diameter from 0.5 to 13 mm.
With the installation of equipment in a quick-clamping single-sleeve chuck, you can easily handle it even with one hand. In the case of two-sleeve, you will have to hold the shaft with one hand and twist with the other.
For cam, it is also required special key. This is not always convenient if you need to quickly change equipment.
- The presence of a percussion mechanism useful if, when tightening the screw, resistance increases and the screwdriver tightens with a higher torque. When drilling stone or concrete, it does not allow the drill to get stuck. 
- Presence of momentum, temporary increases the torque. Suitable for smoothly screwing fasteners into the material, unscrewing stuck fasteners or drills, saves slots on screws. Does not require a tight pressing of the tool, which affects the smoothness of the work. When drilling, it also prevents the drill from getting stuck in the material.
- Availability of 3 speeds of work, allows you to abandon the drill at home, since you can always increase the number of revolutions, thereby screwing in the screws "with a whistle", and the first speed always gives a decent torque.
- The presence of backlight, this feature is very useful in low light conditions. It happens that during work you do not notice how evening has come and quickly darkened. It didn't take long to work, but it's hard to see. This is where the built-in flashlight comes in handy to finish the job without being distracted by the search. additional sources Sveta.
- Battery indicator, some models have an indicator (located on the battery) to show the charge level. This function is not mandatory, but its presence will help determine how long the screwdriver will last. 
- adjusting ring– when the screw is fully tightened, the chuck stops rotating. Thus, the fastener does not sink into the material, and the tooling is not damaged.
Ergonomics and equipment.
For convenient use of the tool, some manufacturers cover the surface of the screwdriver with rubber pads. The screwdriver does not slip in the hand. If you put it on a slippery surface, it will not go anywhere. The presence of a hook on the handle allows you to hang the screwdriver when it is not needed. In some models, there is a holder for bits on the handle, protection against accidental activation.
The tool is usually sold in a plastic case or bag for storage and transportation. More expensive models, are equipped with a set of bits and a second battery. If possible, be sure to hold / twist the screwdriver in your hand before buying, as it is for you to work with this tool. 
Summarizing
- A screwdriver for home / cottage: a network one is quite enough. It is more affordable, has a small weight, and the socket is always nearby. But if you want a cordless screwdriver, then you should choose Ni-Cd and Ni-Mh. If you use it infrequently, the battery will last much longer.In such cases, when regular use is necessary, not a day without downtime, the presence Li-ion battery 100% return on investment. The life of a Li-Ion battery is shorter, but, in this case, lying idle is a waste of money.
At home, a torque of 10-20 N * m will be enough. If a wider range of work is planned and finances allow, then 25-35 N * m. Capacities of 1.5-2 Ah are enough for all occasions.
Screwdriver for professional use: the way you have to work is not always in convenient places, it would be better to choose a smaller device. A justified purchase would be a Li-Ion screwdriver with a large torque of 35 N * m and above, depending on the type of material.
If a man is a jack of all trades and likes to spend repair work in his house, then he probably has a complete set necessary tools. Among them, a screwdriver - depending on its power, it can also be called an electric screwdriver and a drill - occupies a significant place. Those who make often or do such work all the time have long appreciated the undoubted advantages of a cordless screwdriver, its convenience, mobility and ease of use. Do you know how to choose the right cordless screwdriver so that it becomes your reliable assistant in household chores?
What is this tool and what is it for?
Whether you live in an apartment or a private house, you still have to carry out minor repairs from time to time. And this is where a screwdriver comes to the rescue - manual electric tool with adjustable torque, that is, the force with which it can:
- drill holes in surfaces of almost any material - drywall, soft and solid wood, concrete and metal;
- screw and unscrew any fasteners- screws, self-tapping screws, nuts, screws, bolts;
- drag out anchor bolts when mounting;
- cut a thread into small details from metal.
Professional builders and repairers use screwdrivers regularly. It's hard to imagine more handy tool to fix, for example, drywall sheets when finishing works, installation of windows and doors. In general, a screwdriver is necessary in any home where they are used to solving construction and repair issues on their own.
Cordless screwdriver consists of the following elements:
- housing with an electric motor that provides rotation;
- clamping cartridge;
- a rotary coupling attached to the gearbox, which regulates the twisting force, with a scale applied to it, in the common people - a ratchet;
- nozzle bits (screwdrivers), which are fixed in the cartridge, as well as additional nozzles for drilling holes and threading;
- tool start button;
- rotation speed switch;
- reverse switch (reverse);
- removable battery.
With a cordless screwdriver, you can work anywhere in the apartment
Why is it worth giving preference not to the usual, but to the cordless screwdriver? Devices powered by a wall outlet are not limited in operating time, you do not have to charge them. But they have a significant disadvantage: with such a screwdriver, you will not go far from the outlet. Of course, you can use an extension cord, but you have to adjust to the constantly interfering cords. Cordless screwdriver will not cause such inconvenience. You can easily work with it anywhere in the house, yard or take it with you somewhere where there is a need for work, but there is no electricity. Mobility is an indisputable advantage of such a tool. True, the operation of such a screwdriver directly depends on the battery charge level, but high-quality batteries significantly increase the operating time of the device.
Any power tool is a device with certain functions necessary for work, and this significantly affects its price. The cordless screwdriver is no exception. If you buy it for regular use, you need to pay attention to the characteristics of the device, which will become the main selection criteria:
- the shape, ergonomics and size of the tool, as well as its weight;
- type of battery and its capacity;
- indicator of maximum torque (effort);
- the presence or absence of a shock function;
- the maximum possible diameters of drilling in wood and metal;
- device equipment.
In addition, of course, you should take into account the price of the product and the name of the manufacturer. But we will talk about these parameters later, and now we will consider in detail the listed criteria.
The indicator of the number of speeds, according to experts, is not decisive when choosing a tool. Most screwdrivers have two speeds, but due to the presence of other working settings, the difference in the course of work is not always noticeable.
Most modern models of cordless screwdrivers have keyless chucks, which are suitable for any bits and drills. Some models have sockets for hex bits. The choice of cartridge, as a rule, is motivated by individual criteria for ease of use, it cannot be said unequivocally that one type is better and the other is worse.
Shape, size and ergonomics
These characteristics may not seem the most important to you if you do not classify yourself as a home craftsman. But for professionals who work with a screwdriver all the time, they are very relevant. For example, tool size. Its importance can be seen from two sides.
Screwdrivers are not big size very comfortable due to the relatively low weight. With such a device, you can easily get into hard-to-reach places, and your hands do not get tired at all. But small screwdrivers do not have much power, and therefore it will be more difficult for them to screw a self-tapping screw into a hard material.
Cordless screwdrivers of the most small size- hammerless screwdrivers - light and easy to use
Instruments bigger size, unless these are the simplest cheap models of unknown brands, as a rule, they are heavier and more powerful. The relative inconvenience of their use is offset by the ease of working with durable materials. If you often have to drill, then large powerful models are your choice.
Large, powerful cordless screwdrivers suitable for professional construction and repair work
Before buying, think about how often you will use a screwdriver. If you need it several times a month for small domestic work, you should not purchase an expensive large-size model with high power. It is better to take a compact tool from the budget line.
The ergonomics of the tool is also very important. In some cases, you may have to hold a working screwdriver in your hand for several hours, and its weight, as well as vibrations, will affect your hand fatigue. The location of the barrel relative to the handle largely determines how comfortable it will be for you to use the tool. Before buying, hold the screwdriver in your hand, twist it to the sides, simulating work.
When choosing a cordless screwdriver, consider what duration and intensity of work you will perform with it.
In some models, the angle between the handle and the barrel is sharp, after long work with such a screwdriver, calluses on the palm of your hand may occur. The location of the handle at a right or obtuse angle is much more convenient.
Battery type and capacity
Since we are talking specifically about cordless screwdrivers, then the heart of the tool - the battery - needs to be discussed separately. The quality of the device depends to a large extent on it. On the modern market tools are available with three types of batteries:
- nickel cadmium (NiCd),
- nickel-metal-hybrid (NiMH),
- lithium-ion (Li-Ion).
Naturally, each type has its own advantages and disadvantages. How significant they are in a particular case is a purely individual matter, but it is worth considering them in detail.
Table: comparison of batteries of different types
| Battery type | Advantages | disadvantages |
| Nickel Cadmium (NiCd) |
|
|
| Nickel Metal Hybrid (NiMH) |
|
|
| Lithium-ion (Li-Ion) |
|
|
Of course, for home use, buying an expensive tool with a lithium-ion battery is not always advisable. The most objective choice would be a screwdriver on a nickel-metal-hybrid or nickel-cadmium battery. But if you are professionally engaged in repair and finishing works, it is better to pay attention to models with a lithium-ion battery: the price will pay off quickly, and you will get a convenient and maximum reliable tool.
Li-ion batteries different long work, high capacity and no "memory effect"
Battery capacity too important parameter. Often inexpensive models screwdrivers are equipped with a 1.3 A / h (Amp / hour) battery. For example, if you are building plasterboard ceiling at an average pace, one charge of such a battery will be enough for 3-4 hours. And since the charging time is not more than an hour, you can not be afraid of downtime at work. Mega-power impact drivers are equipped with 2 or 3 Ah batteries. Many of these models do an excellent job of drilling metal and hard rock tree.
In the simplest screwdrivers intended for use in everyday life, maximum speed the rotation of the cartridge is about 500 rpm, then for professional powerful tools it reaches 2000 rpm.
The optimal battery voltage for a screwdriver is in the range of 10-14.4 volts. The larger it is, the higher the maximum torque will be.
Torque - adjustable ratchet force
The concept of torque defines the force applied by the tool relative to the screw being screwed, or the force of resistance to the load. For domestic use screwdrivers with a torque of 10–15 N m (Newton meters) will be optimal. At professional models this figure reaches 130 Nm, so they do a good job even with drilling in very hard materials.
The higher the torque of the screwdriver, the better it will cope with drilling in hard materials.
For screwing conventional self-tapping wood screws up to 150 mm long, a force of 10–15 N m is sufficient.
According to the simplest logic, the higher the battery voltage, the more torque the tool has. However, this is not the case with professional models, for example, many 12-volt models have high torque - from 24 Nm and above. Whereas for simple household models, in order to achieve a force of 20 N m, the screwdriver must have increased power, most often this is the level of 18–24 volts.
A clutch for adjusting torque, with a scale applied to it, usually from 1 to 20, is called a ratchet. It works on the same principle as shifting gears in a car. The smaller the number set on the ratchet, the less force the tool uses to tighten the screw. With the help of a ratchet, you set the tightening force limit, above which the engine starts to idle, and the rotation of the cartridge stops. You need to know that the scale of numbers on different screwdrivers indicates different levels of torque, that is, position “3” for one tool does not match the position “3” for another in terms of force.
It is worth making several test runs before starting work, changing the ratchet indicator, and only then, having chosen the right position, get down to business.
Impact function and drill diameters
Both the length and diameter of the screw being screwed depend on the torque indicator. The more powerful the tool, the thicker and longer screws they can tighten. In addition, you can drill with such a screwdriver hard materials. For example, a device with a torque of 36 Nm will perfectly drill wood with a drill with a diameter of up to 25 mm. A torque of 80 Nm indicates that the tool will cope with drilling holes with a diameter of 65 mm.
The overpayment for the impact function of a screwdriver is relatively small, so it makes sense to purchase such a tool for working at home. It will perfectly cope with drilling not only wood, but even metal in small volumes.
If you are engaged in construction and you need to drill a lot of holes in concrete, then it is still better to buy a hammer drill: even the most powerful screwdrivers will not cope with such work.
Equipment
The standard minimum set in which screwdrivers are supplied usually includes:
- plastic case;
- the screwdriver itself;
- batteries in the amount of 2 pieces;
- Charger;
- bits (from 1 or more pieces);
- instructions.
Some manufacturers may add a flashlight and an extra set of bits as a bonus.
Some manufacturers offer an extended set of screwdrivers with a convenient case, a flashlight, additional set nozzles
Rating of cordless screwdrivers from different manufacturers
The modern power tool market offers a huge range of cordless screwdrivers from both worldwide famous brands, and from less popular firms. We offer you a rating of these devices, compiled based on the materials of the Yandex.Market resource.
Table: popular models of screwdrivers
| Model, manufacturer | Specifications | Max Torque | RPM | Battery | approximate cost | User rating |
| Makita DDF343SHE |
| 36 Nm | 1300 |
| 7700–13000 rubles | 5 out of 5 |
| DeWALT DCD730C2 |
| 57 Nm | 1900 |
| 12500–19000 rubles | 5 out of 5 |
| Interskol DA-10/14,4M2 |
| 17 Nm | 1400 |
| 4000–6000 rubles | 5 out of 5 |
| Makita TD090DWE |
| 90 Nm | 2400 |
| 7500–11500 rubles | 4.5 out of 5 |
| Bosch PSR 7.2 Li Case |
| 10 Nm | 240 |
| 4500–6500 rubles | 4.5 out of 5 |
| Hilti SFC 14-A |
| 45 Nm | 1700 |
| 17000 r. | 4.5 out of 5 |
| Black & Decker EPC12CA |
| 11 Nm | 750 |
| 2300–4100 rubles | 4 out of 5 |
| Hitachi DS12DVF3 |
| 26 Nm | 1200 |
| 4800–10000 rubles | 4 out of 5 |
Screwdriver torque is a significant parameter that you need to pay attention to when choosing. It must be taken into account whether the tool will be used for homework or professional. On sale today there are various models that differ in their characteristics.
There are many models of screwdrivers from various manufacturers on the construction market, which differ depending on the power source, parts and functions.
Screwdriver models
A screwdriver is the most commonly used tool, which is indispensable for construction and repair types activities. Today, manufacturers offer a variety of models that can be used for various conditions. This tool is useful for handmade, it is necessary for tightening / unscrewing screws, screws, self-tapping screws, for drilling and even for stirring building mixtures.
According to the power source, the tool is classified into:
The cordless screwdriver is powered by the battery included in the kit.
- Rechargeable models powered by special batteries. They increase the weight of the tool, but make it easier to work in hard-to-reach places.
- Network devices that require connection to the electrical network. They have a limited reach due to the length of the cord, although extensions can be used.
According to the purpose, the equipment can be divided into:
- models for construction/repair work;
- for production shops, workshops, auto repair shops;
- for industrial enterprises;
- for domestic use.
There are professional, semi-professional, household models on sale. When choosing, attention should be paid to the torque, which shows what kind of work the screwdriver can handle.
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What is meant by torque?
Torque is a value that allows you to determine the level of load on the equipment. Which option to choose? It is usually equal to 5-10 Nm, this is quite enough for the safe and high-quality operation of the tool. This parameter is provided for most household and semi-professional models that can easily cope with tight self-tapping screws, drilling steel, concrete.
What should be the torque? You should pay attention to what the instrument will be. For example, for a universal device, rather high torque values \u200b\u200bmust be selected so that the tool can equally well cope with any type of work, be it self-tapping screws or structurally rigid materials. If you need a tool only for drilling wood, then you can prefer a model with a small moment from among the household ones. When choosing, pay attention to the number of revolutions. For example, 400-500 is enough for screwing screws. For drilling hard surfaces, it is best to use devices with a speed of 1200-1300 per minute.
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Torque to screw diameter ratio
When choosing a battery or corded screwdriver it is important to correctly determine the ratio of the screw diameter and speed. Such a dependence is not too difficult to determine:
For driving screws different diameter needed different speed rotation.
- If the screw diameter is 6 mm, then the rotational speed during screwing will be 10 Nm. For structurally soft or hard materials, the frequency will be 25 Nm.
- If the screw diameter is 7 mm, then the torque when working with hard materials will be 27 Nm, and for soft materials- 11 Nm.
- At maximum diameter screw in 8 mm, the torque will be equal to 30 Nm.
What does this ratio show? It is possible to determine exactly what torque can be used for a certain working screw diameter. Right choice will not only make the work more efficient, but also improve the quality, reliability, and durability of the equipment. The operation will be completed much faster, the operator will spend less effort.
For network equipment, high power has little effect on the operation process, and batteries run out quickly. Therefore, it is necessary to have spare batteries and the ability to charge those already planted. Usually for professional tool manufacturers provide spare batteries, but for more simple models at least one battery will have to be purchased separately. When choosing a screwdriver, it is necessary to take into account the presence of another function - reverse. It is necessary in the event that the drill is stuck in the material. Such a reverse is usually electronic; to control it, you should use a two-position switch, which is located near the start button.
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Which torque is better?
A screwdriver is a tool that is necessary for carrying out various kinds works. This is not only construction, but also many home repairs, such as assembling furniture, installing communications. To choose the right equipment, you should pay attention to the torque, which affects the comfort and quality of work. For example, to assemble furniture, too powerful a tool is not needed. If you plan to install interior partition, then you need to take more professional equipment that will perfectly cope with the task.
Drills and screwdrivers are used for mixing building mixtures, you just need to purchase a construction mixer nozzle.
The torque of such tools must be sufficient to be able to mix even the most viscous mixtures and solutions, to ensure their uniformity and high quality.
For mixing concrete and other viscous mixtures, special nozzles are used.
If you want to use nozzles for mortars, then the torque must be sufficient to cope with mixtures of not only low viscosity, but also high. The choice of model depends on the planned work. If a screwdriver is required to be used for mixing liquid mixtures, then the torque may not be too high. If the tool is purchased to work with viscous mixtures, then it is already necessary to prefer professional fixtures, whose turnover is high.
Equipment that will be used for a variety of jobs must have a speed controller. Then the torque can be changed depending on what kind of work needs to be done. When choosing a screwdriver, you need to make sure that the lock for the control button always works, and not only at maximum effort. In the first case, the tool can be used for any work with the most convenient conditions. The torque value can be changed. It is recommended to buy models that have manual or electronic control. They have a special step-down transformer that works great with liquid mixtures when the voltage goes down.