Comparison Grand APC-20V/8-4 Professional vs Edon UCS-21/25BL

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.

— 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.

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 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.

The time required to fully (from zero to 100%) charge the battery in the cordless saw (see "Power supply"); this refers to the complete battery and standard charger. The shorter this time, the shorter the breaks will have to be done for recharging; however, higher capacity batteries inevitably take longer to charge than smaller ones. This can be compensated by the use of fast charging technologies, but they, in turn, affect the cost of the tool.

The handle in the upper plane of the saw body for the convenience of carrying the tool and holding it when performing work. Also , the top handle helps guide the saw in the right direction during work.

The volume of the oil tank provided in the tool.

In this case, we mean a tank from which oil is supplied to the saw chain (see "Device") to lubricate it during operation. In general, this is a reference parameter that allows you to estimate how much oil is needed for one refueling of the tool.