Comparison Grand DA-21U/Li vs Grand DA-12U Pro

The speed of rotation of the working nozzle provided by the tool.

If a single number is indicated in this paragraph (for example, 1800), it can be either a standard, constant, or maximum rotation speed. This refers to the maximum speed if the tool has more than one speed (see "Number of speeds") and/or a speed controller (see "Functions"). In turn, two or three numbers through an oblique line (for example, 1100/2300/3400) are indicated only for models that have the corresponding number of individual speeds. Each of these numbers indicates the standard (and in the presence of a speed controller — the maximum) number of revolutions at one of the speeds.

Anyway, when choosing a tool by the number of revolutions, it is worth considering both its general type (see "Device") and the specifics of the intended work. Detailed recommendations on this matter are quite extensive, it makes no sense to give them in full here — it is better to turn to special sources. We note only a few general points. So, high -speed drills nowadays are considered to be drills capable of delivering more than 3000 rpm. In general, high speed contributes to productivity, but there is also a downside: increasing the speed (for the same power) reduces torque — accordingly, the efficiency of working with stubborn materials and large diameter nozzles decreases. Therefore, it makes sense to specifically look for a "high-speed" tool only if speed is of key impor...tance; it doesn’t hurt to make sure that the model you choose can provide the required efficiency and torque.

Torque is the maximum force with which this model is capable of turning the working nozzle.

Higher torque gives more options, it allows you to cope with complex tasks such as drilling in hard materials, unscrewing stuck screws and nuts, etc. On the other hand, a lot of force requires corresponding power — and this, in turn, affects the dimensions , weight and cost of the tool itself, and also puts forward increased power requirements (mains power, battery capacity or pressure / compressor performance). And for some tasks, excessive torque is basically unacceptable, so for maximum versatility, it is desirable to have torque control — and this affects the cost even more. And the more steps, the more optimally you can configure the tool to perform a particular type of work. So the general rule is this: when choosing, it is worth considering the specifics of the planned work, and not chasing the greatest working effort.

Detailed recommendations on choosing the optimal torque for different types of tools (see "Device") can be found in special sources. Here we note that it is of key importance primarily for screwdrivers, although it is also given for other types of tools. At the same time, in the “weakest” models, the maximum working force does not exceed 15 Nm, in the most powerful ones it is more than 150 Nm.

The total weight of the tool is usually the device itself, without attachments. For battery models (see "Power Source"), usually, the weight is indicated with a standard battery installed; for battery-powered models, the weight can be given both with and without batteries, but in this case this point is not particularly important.

Other things being equal, less weight simplifies work, increases accuracy of movement and allows you to use the tool for longer without tiring. However, note that high power and productivity inevitably increase the mass of the tool; and various tricks to reduce weight increase the price and can reduce reliability. In addition, in some cases, a massive design is more preferable. First of all, this applies to work with a large load — for example, drilling holes of large diameter, or making recesses with impact: a heavy tool is more stable, it is less prone to jerks and shifts due to uneven material, vibration of mechanisms, etc.

It is also worth noting that specific weight values are directly related to the type of tool (see "Device"). Screwdrivers are the lightest — in most of them this figure does not exceed 500 g. Screwdrivers and drill drivers are more "heavy": their average weight is 1.1 – 1.5 kg, although there are many lighter ( 0.6 – 1 kg) and heavier ( 1.6 – 2 kg or more ) models. And clas...sic drills and wrenches have the greatest weight: such a tool must be quite powerful, so for them 1.6 – 2 kg is an average, 2.1 – 2.5 kg is above average, and many units weigh more than 2, 5 kg.

The largest diameter of holes that the tool can make when drilling with a conventional drill in wood.

The larger the hole diameter, the higher the resistance of the material, the more power the tool must provide and the higher the load on it. Therefore, the maximum allowable drilling diameter must not be exceeded, even if the chuck allows you to install a thicker drill bit — this can lead to tool breakage and even injury to others.

It is worth noting that some types of wood can have a fairly high density, and for them the actual allowable drill diameter will be, accordingly, less than the claimed one. However, this is true mainly for exotic breeds, which are extremely rare in our area.

The largest diameter of holes that the tool is capable of making when drilling with a conventional drill in metal.

The larger the hole diameter, the higher the resistance of the material, the more power the tool must provide and the higher the load on it. Therefore, the maximum allowable drilling diameter must not be exceeded, even if the chuck allows you to install a thicker drill bit — this can lead to tool breakage and even injury to others.

Also note that the drilling diameter for metal is usually indicated based on medium hard steel and other similar materials. For metals and alloys that have a significantly higher hardness and density, the allowable drill thickness will be less; however, such situations occur infrequently, and if you wish, you can find out about the features of working with various alloys x in special sources.

- Corner nozzle. A nozzle that allows you to rotate the axis of rotation of the cartridge by 90 ° relative to its original position. Such a device is indispensable for making holes, as well as twisting and unscrewing fasteners in some hard-to-reach places (for example, in narrow grooves or a profile).

- Eccentric nozzle. Replaceable nozzle designed to shift the axis of rotation of the cartridge slightly away from its original position. In this case, the direction of the axis remains the same. Like the corner nozzle, such a device is intended mainly for working in certain hard-to-reach places (in particular, near walls and edges of workpieces).

- Additional handle. A modern tool, even a relatively low-power one, can be quite massive, and for maximum accuracy and reliability it may be necessary to hold it with two hands at once. Using an additional handle for this is more convenient and safer than looking for a place to grip on the body. The handles themselves are usually mounted near the cartridge perpendicular to the axis of rotation and may have different design features.

- Depth stop. A device that allows you to limit the depth of drilling. The most popular version of such a limiter is a rod in a special mount, installed parallel to the drill. Before starting work, this rod is shifted so that when the desired depth is reached, its end rests on the surface of the material,...preventing the drill from moving further.

- Store nozzle. It looks like a kind of store or disk, into which a tape with self-tapping screws is “charged”; and a special block is installed in front of the cartridge, designed to supply self-tapping screws. This design allows you to tighten the screws as quickly as possible and without unnecessary movements: just load the tape from the magazine into the feed unit, start the engine and alternately press the working part of the tool to the desired points on the material.

- Lantern. A classic flashlight for illumination in low light conditions, in contrast to the built-in illumination system, is a separate device. Such a separate device is not very convenient to hold in your hand during work - in such cases you can’t take the tool with both hands, and this creates problems in some situations. On the other hand, often the situation allows you to put or hang a lantern without taking up your hands; and sometimes in this way you can even organize the lighting more successfully than using the built-in backlight. In addition, the flashlight can be used independently.

- Case (bag) included. The presence of a case or bag in the delivery set of the drill. Cases are usually called hard suitcases; bags, unlike cases, are soft, which allows them to be packed more tightly together with other things, but reduces the degree of protection. In any case, this feature makes the tool more convenient to store and carry: the complete bag or case is optimally suited for this model, in addition, they can hold drills, spare batteries and other additional accessories.

- Rack. Mostly professional drills for diamond drilling are completed with racks(see "Purpose"). This design is a stand (base) with a guide rail fixed on it, along which the tool can move using a special mechanism. According to the fastening of the rail, the racks are divided into two types:

• Non-inclined stand. A structure with a rigidly fixed rail, which is usually located vertically, perpendicular to the base; accordingly, the axis of rotation of the installed tool also remains always vertical. Such racks have more limited capabilities than inclined ones. On the other hand, they are simpler, cheaper and more reliable (there is no movable mount in the design that can become loose); and for most work, the vertical position of the tool is fine.
• Tilt stand. Stands in which the rail is fixed on a swivel mount and can deviate from the vertical at a certain angle. Accordingly, such a device allows you to direct the crown not only vertically, but also at an angle; this can be important for some non-standard tasks. On the other hand, a movable structure is more complex, expensive and less durable than a fixed one; therefore, it is worth paying attention to this option if the possibility of inclined drilling is fundamental for you.

- A set of drills. The presence of drills in the kit eliminates the need to purchase them separately and allows you to use a drill (or other tool with drill functions) right out of the box. True, the specific assortment of drills can be different - besides, it is often an entry-level set of 5 to 7 devices for the simplest tasks like drilling wood. However, even such a set will be useful if the tool is purchased for domestic use or simple work that does not require specialized nozzles. We also note that such equipment is especially convenient when buying a “first tool for a beginner”, when there are no drills on the farm yet and one way or another you will have to buy them.

- A set of bits. Bits, we recall, are nozzles in the form of screwdriver heads, which are also used in screwdrivers. As in the case of drills, the presence of such nozzles in the kit eliminates the need to purchase them separately and makes it possible to use the tool immediately after purchase. The specific set of bits is worth specifying further, but most often it includes at least flat and cross bits in a fairly large variety of sizes. And in general, such sets are quite extensive - even in relatively inexpensive tools, the number of complete bits can be measured in tens.

- Equipment. The term "equipment" means at least several types of working nozzles, and sometimes additional accessories. For example, if such equipment is indicated for a drill-driver, then this model is almost guaranteed to be equipped with both drills and bits (and possibly more specific accessories). A specific set of equipment should be specified separately.

- Extension. The purpose of such an accessory is clear from the name: it allows you to increase the working length of the tool. In other words, when you install an extension bat or other equipment, it is further from the body; the extension itself is made quite thin. This accessory is used mainly in models with the functions of a screwdriver or wrench: it allows you to reach deep-seated fasteners that are inaccessible in the usual configuration. And in many models, the extension cord is also made flexible, which further expands its capabilities.

- Magnetizer. Device for magnetizing bolts, screws and other similar fasteners. Found in individual screwdrivers; the working tooling of such tools is also made of magnetic material, due to which the magnetized fastener effectively “sticks” to the tooling and does not need to be supported separately.

- Case insert. Interchangeable insert (or several inserts) to adjust the complete case to the specific situation. For example, a regular insert can only have space for a tool and a charger, and a replacement one can also accommodate a second spare battery. Specific features should be specified separately.

- Charger(charger). A device for charging the batteries used in the tool with the appropriate power supply. For models supplied with such a device, the charger model may be additionally specified in the characteristics. This information can be useful not only for finding a spare or replacement charger, but also in case the household has other cordless tools and / or batteries for them. The fact is that many manufacturers nowadays use universal batteries that are compatible with a whole set of tools from the same brand; so, for example, a complete charger for a drill may be quite suitable for a cordless grinder from the same manufacturer.
On the other hand, a lot of modern cordless tools come without a charger at all. This option will be optimal, first of all, if a compatible memory is already available, and there is simply no need to overpay for a second device. In addition, the lack of a charger will be appreciated by those who want to choose this accessory separately, without relying on the manufacturer's decision.


Note that the above list is not complete - modern tools can be supplied with other additional items, including very unexpected and original ones - like a fitness tracker or even a radio-controlled car.

Rated battery voltage for which the cordless tool is designed (see "Power Source").

Manufacturers select the battery voltage taking into account the performance characteristics of the tool and the power supply required to achieve these characteristics. In fact, this means that most often this parameter can be ignored at all when choosing. The only exceptions are some specific situations — for example, if the "household" already has a battery of the same company and you want to evaluate its compatibility with the selected model, if the selected tool is supplied without a battery and you want to immediately order a power source for it, or for accurate comparison of batteries by capacity (see below for more details). But after the purchase, the voltage data can also be useful for finding chargers in addition to or to replace the "native" charger.

As for specific values, in many models the voltage does not exceed 10 V — this is often quite enough. However, much more popular options are 11 to 15 V and 16 to 20 V. There are also higher voltages, but much less frequently.

The time to fully charge the battery that the tool is equipped with from a standard charger (when using other batteries or a “non-native” charger, this time may vary both in one direction and in the other).

For cordless tools in general, see "Power Source". And charging time data gives you an idea of how you'll need to organize your workflow and how long breaks you'll need to charge your batteries. The specific duration of the process will depend both on the capacity of the battery (ceteris paribus, a more capacious model takes longer to charge), and on the technologies used by the manufacturer that increase charging efficiency. However, in general, it is customary to refer to tools with a good charging speed as models where this procedure takes no more than 45 minutes.

We also note that the specific meaning of this parameter also depends on the number of batteries in the kit. Recall that there are often several of them at once (see "Complete battery"), and while one battery is working, the rest can be charged. This allows you to reduce interruptions to a minimum, and even completely do without them. But if there is only one battery, charging breaks will inevitably be required in full. This is especially true for tools with a built-in power source (in models with replaceable batteries, the situation can be corrected by purchasing additional batteries).