Comparison DeWALT DWS780 vs DeWALT DW717XPS

The maximum speed of the disk, provided by a saw of the appropriate design — disk, cut-off, etc. (see "Device").

Note that most of these saws use gearboxes, so that the blade revolutions are much lower than the engine revolutions (see above). This achieves an increase in torque, which in the case of saws is often more important than the high speed of the blade.

As for the specific number of revolutions, it is first of all worth noting that only saws with the same disc diameter can be compared according to this indicator. In these cases, higher speeds provide better performance, but the trade-off is reduced torque; such saws do better with relatively "light" materials. Conversely, low speeds reduce productivity, but allow the blade to effectively "bite" even into dense, stubborn workpieces. More specific recommendations regarding the choice of a saw according to the number of revolutions of the blade can be found in special sources.

The largest tyre size (in chain saws) or disc (in circular saws and some others, see "Device") that is allowed for this tool. Tyres are sized by working length, rims by diameter.

A larger bar/wheel allows for deeper cuts but requires more powerful motors. Therefore, this parameter cannot be exceeded — this can lead to an overload of the engine with all the corresponding troubles. However, in many models with a disc it is physically impossible to install a nozzle with a diameter larger than the maximum allowable.

Also note that saws with similar bar/blade sizes may differ in maximum depth of cut (mostly due to differences in design or power). As for the specific dimensions, they depend on the type of saw (see "Device"). For example, large discs of 450 – 500 mm are found exclusively in stationary chain saws, the maximum figure for cutting models is 400 – 450 mm, for trimming — 300 – 350 mm, and sizes of 500 – 550 mm or more clearly indicate that speech It's about a chainsaw chainsaw bar. Detailed recommendations regarding the choice of a tool for a given size can be found in special sources.

The greatest depth of cut provided by the saw.

In most types of saws (see “Device”), the depth of cut directly depends on both the engine power and the size of the tyre / disk. The specifications give a value for the maximum allowable size of the working nozzle; when using nozzles of a smaller size, the depth of cut, respectively, will be less. But in band saws, this depth is rather weakly related to the actual length of the tape — it is determined primarily by the length of the open section of the tape, which is directly involved in the work.

Anyway, the greater depth of cut makes the tool more versatile, but comes at the cost of weight, price, and electricity/fuel consumption. So when choosing, it is worth considering the real features of the planned work and the dimensions of the workpieces that are planned to be cut. As for specific values, the most modest tools provide a depth of up to 50 mm ; 50 – 75 mm is considered a low indicator, 75 – 100 mm is average, 100 – 125 mm is above average, 125 – 150 mm is already quite an impressive thickness, and the most powerful modern saws can have a cutting depth of more than 150 mm.

Maximum cutting depth achieved when sawing at a 45° bevel.

This feature is indicated only for those models that are originally designed for sawing at an angle — for example, due to the special design of the attachment for the blade / blade (in stationary models, see "Type") or due to the inclined support platform (in manual) . The maximum angle of inclination of the saw in such models can be different (see below for more details), however, 45 ° is considered the standard option, so it is for this inclination that data on the depth of cut is given.

The general meaning of this parameter is quite obvious. On the one hand, a greater depth of cut allows you to cope with thicker workpieces and generally gives you more options; on the other hand, an increase in depth requires an increase in the size of the disk / canvas and an increase in power, which, accordingly, affects the price, dimensions and consumption of electricity / fuel.

The kerf width determines the maximum size of the cutting line, and therefore the maximum width of the workpiece that the saw can cut through in one go. The value of the kerf width depends primarily on the diameter of the saw blade. Additionally, the stroke of the broach mechanism should also be taken into account. Saws with a pulling mechanism provide a cut that exceeds the diameter of the cutting blade.

The maximum angle at which the working part of the saw can be tilted relative to the vertical. It can be indicated not only for stationary tools, but also for manual ones — in the event that the design provides for a support platform. It is worth paying attention to this parameter if you have to deal with oblique cuts: making such cuts by setting the saw to a certain angle is much more convenient than adjusting this angle manually.

— 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.

The noise level produced by the saw during operation. Note that this parameter is rather approximate, because in fact, the “loudness of the work” depends not only on the tool, but also on the material being processed and the characteristics of the environment. Nevertheless, the data given in the characteristics make it possible to assess the comfort of working with the tool. The lower this indicator, the less discomfort the noise will cause, and at high values, even special hearing protection may be needed.

Note that the noise level is usually measured in decibels, and this unit is not linear: for example, a difference of 3 dB corresponds to a difference of 2 times, 10 dB — to 10 times. Therefore, it is easiest to evaluate the noise level using comparative tables. Here is a simplified version of such a table for the range in which modern saws operate:

70 dB — loud conversation of several people in close proximity;
75 dB — a cry in the immediate vicinity;
80 dB — truck engine, mechanical alarm ringing;
85 dB — loud scream;
90 dB — freight car at a distance of 7 – 10 m;
95 dB — subway car at a distance of 7 – 10 m;
100 dB — industrial shop;
110 dB — tractor engine;
120 dB — demolition hammer, thunder from a close lightning strike (pain threshold of auditory perception).