Comparison Makita DJR187RTE vs Makita JR3070CT

By type of power source, all modern saw can be divided into electric and gasoline. The common difference between them is that electrical units are more compact and lighter, less noisy, easy to maintain and do not produce exhaust gases, so they can be used indoors without restrictions. Petrol tools, in turn, combine high power and independence from power grids, but they are heavy, bulky, more difficult to operate and repair, more expensive (both in terms of their own cost and fuel price) and are generally designed for use outside premises. Therefore, most modern saw are made electric, which in turn can use different types of power:

- Power supply (230 V). Connection to a standard 230 V household network, in other words, a regular socket. This option can be used both in portable saw and in stationary tools of relatively low power (up to 3.5 kW). There are sockets almost everywhere where there is electricity at all, and the operating time of such units is almost unlimited (as long as there is voltage in the network). The main disadvantage of such a power supply is the presence of a power cord that does not allow you to go far from the outlet (and with a portable tool, you also have to make sure that the cord does not get under the canvas).

- Power supply (110 V). Tools powered in the American and Japanese manners - from power networks with a voltage of 110...V. Power tools with such an operating supply voltage are produced for the market of North and Central America, the Land of the Rising Sun, Saudi Arabia. Also, 110 V power grids are found in the UK. To avoid tool failure when connected to standard 230 V household networks, you will need an additional link in the face of a step-down transformer or a special 110 V converter.

- Power supply (400 V). Powered by a three-phase power supply with a voltage of 400 V. Such power is suitable even for high-power saw, but it is far from being available everywhere - basically a three-phase connection is available in workshops, workshops and other industrial premises. Therefore, this option is found exclusively in stationary tools (see "Type") of high power, for which a conventional socket is no longer enough.

- Accumulator. Powered by own battery. The main advantages of this option are mobility, the ability to work independently of sockets and the absence of a power cord that can interfere with work. On the other hand, such a power supply is not suitable for high-power saw, other things being equal, a cordless tool turns out to be noticeably heavier and more expensive than a mains one, and the operating time is limited by the battery charge. However, in most cases, the battery is made removable, which allows you to keep several batteries ready and change them as needed.

- Battery / power supply (230 V). Tools that allow two power options - from an outlet and from its own battery. See above for more details on each option, and their combination makes the saw as versatile as possible. So, if there are sockets nearby, you can work from the network, saving battery power (or even recharging it in the process), and if there is a problem with the sockets or the network cable interferes with work, you can switch to the battery. On the other hand, such versatility affects the price, and the tool itself still turns out to be more cumbersome and heavy than a purely network one.

Saw motor power in watts. For petrol tools (see "Power Source"), horsepower is additionally indicated, see below for details.

The higher the power, the better the tool is suitable for voluminous work and hard materials, the greater the depth of cut it can provide and the easier it can cope with significant loads. In addition, for different types of saws and different types of materials, the actual power values \u200b\u200bcan also be different. For example, a power of 2.5 – 3 kW is actually the limit for chain saws, but in chain saws this is an average figure, among such tools there are models of 3 – 4 kW and even more. Detailed selection recommendations for various cases can be found in special sources.

The highest frequency of blade strokes provided by a reciprocating saw (see "Device") in normal operation. A higher frequency, on the one hand, increases productivity and provides a more accurate cut, on the other hand, it increases the load on the blade and requires a rather high power.

The number of operating speeds provided in the tool. Specified only if there are more than one velocities. The larger this number, the more settings the user has at his disposal, the more extensive the possibilities for setting the operating mode for a particular situation.

Note that in some models, instead of several speeds, a smooth adjustment of the number of revolutions may be provided (see "Functions — preset revolutions ").

— Chain brake. A device that ensures the saw stops during the so-called. reverse kick. In accordance with the name, it is used in chain saw (see “Device”). Kickback can occur, in particular, when the very tip (toe) of the tire comes into contact with the material being processed. The bar and chain are thrown towards the operator, which can lead to injury. To avoid this, a chain brake is provided: during a reverse strike, it stops the saw almost instantly.

— Anti-vibration system. Various design solutions that reduce tool vibration during operation. Strong vibrations, especially long-term ones, negatively affect the quality of work and condition of the tool, and also lead to rapid fatigue of the operator; The anti-vibration system allows to eliminate these phenomena to a certain extent.

— Keyless chain tension. Possibility of adjusting chain tension in chain saw (see “Device”) without the use of special tools - wrenches, screwdrivers, etc. This function is especially convenient in light of the fact that during more or less long-term operation, the saw needs to be periodically checked and, if necessary, the chain must be tightened right on the spot - and this is more convenient to do without unnecessary devices.

— Oil-free saw set. Saws that do not require additional lubrication of sawing equipment. Such models...are unsuitable for long, productive cuts and are suitable for minor work. But the absence of the need for lubrication greatly simplifies the maintenance of the device and “keeping it in shape.”

- Smooth start. A special control system used in electric saw (see “Power source”). Without a soft start, the electric motor “starts” very abruptly, which leads to jerking of the saw and creates the risk of letting go of it. In addition, when started in this way, the tool consumes high currents, creating a significant load on the electrical network. The soft start system allows you to avoid these phenomena: the electronics limit the starting currents of the electric motor, avoiding tool jerks and voltage surges in the network.

— Electronic engine protection. A protection system that turns off power to the saw motor in the event of a critical increase in load - for example, when the disk/chain jams. Such systems are used in electric saw (see “Power source”). They help avoid damage to the unit due to overload. At the same time, we note that the electronic protection is reusable; after it is triggered and the problem is eliminated, it is enough to turn on the power again - and the saw can be used again.

— Brushless motor. The presence of a brushless (brushless) motor in an electric saw (see “Power source”). Such electric motors have a number of advantages over traditional commutator motors: in particular, they are more economical in terms of energy consumption, less noisy, and do not spark, which can be important in conditions of increased fire danger. The disadvantages of brushless motors are complexity and high cost.

— Engine brake. A device that additionally brakes the engine when the tool is turned off. The engine itself (and, accordingly, the working attachment) after switching off can still rotate for quite a long time by inertia; the brake stops this rotation almost immediately, so you don’t have to hold the tool suspended for extra time.

— Safety clutch. A device that protects the operator from sudden jerks, as well as the engine from damage due to a sharp increase in load. In such cases, the overload clutch disconnects the motor shaft, avoiding overload. Note that such devices can be either reusable or disposable - the latter are destroyed when triggered, and to continue operation you will need to install a new coupling.

— Laser marker. A kind of “target designator” that allows you to clearly determine where the cut will go. To do this, a clearly visible line is projected onto the workpiece, the location of which corresponds to the location of the future cut.

— Backlight. Lighting system built into the saw. This feature is definitely desirable when working in low light conditions. However, it can also be useful in bright external light: the place of work is often in the shadow (for example, from the tool itself), and without special lighting it can be difficult to work in such conditions.

— Speed regulator. The ability to limit the rotation speed of the saw motor (and, accordingly, the speed of the blade). This function is essentially a smooth speed control; it is especially useful in cases where full speed is not required - for example, when working with soft materials that require delicate processing.

— Maintaining speed. A function that ensures maintaining a constant engine speed (and, accordingly, a constant blade speed) regardless of the load on the tool. To do this, the tool’s automation regulates the output power depending on the current load: when the load increases, the power increases, when it decreases, it decreases. Permanent operating speed has a positive effect on both the quality of the cut and the service life of the blade and the durability of the entire tool.

— Stationary installation. Possibility of installing a portable saw (see “Type”) in a stationary manner. Most often, this feature is provided in circular saw (see “Device”), and for a stationary installation such a saw is usually turned “upside down” and fixed on a workbench or other base - thus, the sole turns into an impromptu work table. In addition, there are reciprocating saw with a similar function. In them, a stationary installation means the ability to secure the saw directly to the workpiece using a clamp - this allows you to make an even cut without the need to hold the saw suspended and constantly control its position in your hands.

— Water cooling (coolant). The saw has a water cooling system. In this case, we are talking about cooling the workpiece and the blade: water is constantly supplied to the cutting site using a special pump. Thanks to this, the heating of the blade is reduced, its service life is increased, the quality of the cut is improved and the amount of dust generated during sawing is noticeably reduced. The method of collecting water supply may be different: some models need to be connected to a water supply, others are equipped with their own water tanks. Note that water cooling is not required for sawing wood; but when working on stone, concrete and other hard and dense materials, it can be very useful.

— Keyless blade replacement. Possibility of replacing the saw blade without using wrenches, screwdrivers or other special tools. In other words, to replace the blade, the user does not have to look for an additional tool - you can open the fasteners, change the blade and secure it manually.

— Pendulum stroke. The presence of a pendulum function in the reciprocating saw (see “Device”). With this stroke, the blade, making a reverse movement, deviates slightly from the cutting line in the direction opposite to the teeth. This increases the cutting speed, reduces the heating of the blade and makes it easier to remove sawdust from the working area. At the same time, the pendulum stroke somewhat reduces the quality of the cut and is not suitable for curved lines. Therefore, this function is usually made switchable, and in some models it is also adjustable: using the switch you can change the amplitude of the pendulum.

— Display. The display shows important information about the operating modes of the saw. This can be: current strength, cutting speed, number of passes, operating time, etc. The information displayed on the screen depends on the modification of the sawing tool.

— Synchronization with a smartphone. The ability to connect the instrument with a smartphone or other gadget (for example, a tablet) via Wi-Fi or Bluetooth. The mobile application can provide information about the condition of the saw: battery charge level, temperature, etc., and proprietary software often warns the user about the need to service the tool or replace parts. Some stationary saw support remote control from a smartphone (turn on/off, adjust speed, select operating mode, configure various parameters, etc.). Finally, the mobile application can be used to set a password for starting the tool or logging work performed.

- Disc. The presence of a saw blade is included in the delivery set of the circular tool. It can be either one or several, which allows you to use the saw “out of the box” without the need to purchase additional consumables. If you already have a saw blade or intend to select it for specific tasks, it is worth taking a closer look at the configurations without a blade - they are usually cheaper.

- Chain. One or more chains included as standard with the saw. The presence of a chain with teeth for cutting allows you to do without purchasing a separate executive body for chain saw. However, there are configurations without a chain - it is assumed that the customer already has a chain or he will select the required option himself.

— Saw blade. The presence of one or more saw blades in the complete set of a reciprocating or band tool. They ensure that the saw is ready for use literally immediately after unpacking. There are also configurations of reciprocating or band models without a saw blade - they are cheaper, and the customer has the right to choose a suitable blade independently.

— Dust collector. A dust collector is included with the saw. The dust collector is a container for collecting sawdust and other d...ebris generated during operation; As a rule, such a container is made removable. Installing a dust collector slightly increases the dimensions of the entire tool, but this is compensated by cleanliness and convenience: dust and other production waste mostly settle in the container and not on surrounding objects.

- Charger. The presence of a charging block in the package allows you to charge batteries. Accordingly, for models with batteries, this accessory is necessary to power the battery. However, there are models without a charger. And saw with it may differ in the charger model, the name of which will allow you to learn more about its characteristics and, if necessary or if required (breakdown), purchase a similar one.

— Case (bag). Availability of a case or bag included with the instrument. A case is a container-suitcase made of hard material; bags are usually made of soft material. This way the case provides maximum protection and the bag can be folded away compactly when not in use. The specific type of case that comes with the saw should be specified separately. However, in any case, a complete case or bag will be more convenient for storing and transporting the instrument than impromptu packaging.

- Stand. The stand makes the saw tool more stable, reliable and safe. The presence of a stand is typical for stationary type saw. Mostly these are powerful, productive, large and heavy models that are located in a separate place. The stand can be implemented either with classic legs (bed) or with a cabinet with a tool compartment. The stand can be equipped with various types of saw: circular saw, miter saw, band saw, cutting saw and even chain saw (with electric drive).

— Wheels for transportation. Transport wheels make it easy to move sawing equipment around the shop. The presence of wheels will come in handy when the saw needs to be moved a little to install some large workpieces or simply when cleaning the workshop. As a rule, wheels are typical for stationary saw with a table top or work holder.

Features of the battery saw package, regarding the presence of a battery in the kit or the design of the tool. For cordless tools in general, see "Power Source", and the options in this case may be as follows:

— Missing. The complete absence of batteries in the delivery set — they need to be looked for separately. This is associated with certain troubles, but it also provides important advantages. Firstly, the model and number of purchased batteries can be chosen at your discretion, depending on your needs and low-cost. Secondly, a suitable battery may already be “in the household” — especially when you consider that some manufacturers produce universal batteries suitable for different types of power tools of the same brand. Thanks to all this, this option is extremely popular — in fact, most cordless saws come without batteries.

— 1 battery. "Classic of the genre": one removable battery included. The main advantages of this configuration are low cost and at the same time the ability to use the saw “out of the box” without selecting power sources for it. At the same time, when the charge is exhausted, you will inevitably have to take breaks for charging — or still buy another battery. Thus, this option is relatively rare — sets with two batteries are more common.

— 2 batteries. The most popular option among saws supplied with batteries included. H...owever, it is worth noting that in this category there are two types of tools. The first, and most common, is saws for one battery. In such models, the second battery plays the role of a spare, its presence allows you to extend battery life and minimize interruptions for charging: while one battery is in use, the second can be charged. The second variety of saws in a similar configuration are models that initially operate on two batteries (see "Powered by two batteries") and are supplied with power supplies in the kit; this case is analogous to having one battery in a simpler tool (see above).

— 3 batteries. A very rare configuration option: in the presence of a charger for 2 batteries, it allows you to practically eliminate interruptions in charging, but it is expensive and rarely needed (and in cases where 3 batteries are really needed, the required number of batteries can be purchased separately).

— 4 batteries. A variant found among individual models powered immediately by 2 batteries. Essentially the same as 2 batteries for a tool powered by 1 battery; see above for details.

— Built-in. A battery built into the body of the saw and not designed to be removed and replaced by the user. This design somewhat reduces the overall dimensions of the tool, but does not allow you to quickly change a dead battery to a fresh one — the only option is charging, which can take quite a lot of time. In addition, if the battery fails, the tool will, at best, have to be carried to a service centre, at worst, replaced with a new one. Therefore, this option is used extremely rarely — in separate low-power tools that are not designed for high loads and long-term operation.

The name of the battery platform supported by the device. A single battery platform is used to combine various power tools of the same brand into one line (screwdriver, grinder, circular saw, etc.). Devices on the same platform use interchangeable batteries and chargers. Thanks to this, for example, there is no need to select a battery for each individual model of a power tool, because one purchased as a spare battery can be used in various power tools, depending on the situation or as needed. Batteries of the same platform basically differ from each other except perhaps in capacity.

The operating voltage of the battery in the saw with the appropriate type of power supply (see "Power supply"). The more powerful the tool, the higher the battery voltage, usually. At the same time, this parameter is usually selected in such a way as to optimally match the characteristics of a particular model; therefore, in fact, voltage data may be required only when looking for a spare or additional battery.

Note that most often in modern saws one of two standard voltages is used — 18 V or 36 V. Batteries less than 18 V are typical mainly for compact low-power models, and 40 V or more — for heavy units, mostly professional ones.