Comparison ECHO CS-4200ES-15 vs STIHL MS 250 C-BE 35

The volume of the engine of a gasoline saw (see "Power source"). On the one hand, the power and performance of the tool depend on this indicator, on the other hand, its weight, price and fuel consumption. Accordingly, it is necessary to choose a model taking into account the specifics of the planned work, and it does not always make sense to chase large volumes. In particular, for simple household tasks, an engine capacity of about 40 – 50 cm3 is considered quite sufficient, and in professional models this figure can exceed 100 cm3. More detailed selection recommendations can be found in special sources.

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 power of the saw engine expressed in horsepower (hp). This designation is traditionally used in gasoline models (see "Power Source") along with watts; 1 HP ≈ 735 W.

For more information about power, see the paragraph of the same name above.

The highest speed that the saw engine is capable of delivering in normal operation.

We emphasize that this parameter should not be confused with the maximum disk speed (see below) — here we are talking exclusively about the speed of rotation of the motor shaft. It can be specified for all types of saws, not only for models using discs. However, in general, engine speed is more of a reference than really significant information. In fact, it is needed mainly for some specific tool maintenance tasks; when choosing, it is better to focus on indicators that are more “close to life” — engine power, cutting depth, chain / tape speed or disk speed, etc.

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.

Regular chain pitch for which the chain saw is designed (see "Device"). A step is the distance between two adjacent chain teeth; the greater this distance, the higher the productivity of the saw, however, for a large step, higher power is required, and the cut is rougher. Therefore, this parameter largely determines the class of the saw and the specifics of the work for which it is designed. The current standard options are:

— 1/4". The smallest size, found in a low power tool — 1-1.5 hp. It has not received wide popularity due to poor performance.

— 0.325 ". One of the most popular options among amateur-class tools. Saws for such a chain have a power of up to 3 – 3.5 hp, they are suitable for both cutting branches and felling trees of small thickness.

— 3/8 ". He is 0.375". Slightly larger pitch than 0.325" is better suited for rough scale work. Also considered a household and semi-professional option, very popular.

— 0.404 ". The largest tooth pitch in modern chain saws. Rare, used in the most powerful professional tools designed for heavy work — for example, logging.

Note that it is allowed to install chains on saws with a finer pitch than the regular one, but not with a larger one. The latter is fraught not only with a decrease in the quality of work, but also with a critical increase in loads, with the possibility of tool breakage.

The maximum speed of the chain relative to the material that a saw of the appropriate design can provide (see "Device"). Higher speed allows to achieve faster and cleaner cuts, but requires more engine power; low speed, in turn, reduces productivity, but allows you to achieve good traction with a relatively low engine power. More detailed recommendations regarding this parameter can be found in special sources.

— 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.

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).