Comparison Sturm GC9939 vs Makita 2712

The device describes first of all the general principle of operation of the saw. The variety of modern saw is quite large: chain saw, ( band saw ( for wood and metal), reciprocating saw (including alligators), circular saw (including gas cutters), miter saw, cutting saw, combined saw, radial-cantilever saw. Here are the main features of these varieties :

- Chain. Saws, the working element of which is a chain with teeth of a special shape. The chain is closed in a ring and during operation moves along an oval-shaped guide bar. In common parlance, the name “chainsaw” most often means this particular type of saw, but chain units can also be electric. In general, chain saw are widely used both for wood (felling trees, trimming branches, etc.) and for other materials - in particular, for concrete and ice. Almost all instruments of this design are portable (see “Type”)

— Tape on wood. All band saw use a looped metal band with teeth as a working element. At the same time, unlike chain models, there is no tire in the design, and the necessary rigidity of the belt...is achieved solely through the tension between two rollers. As for tape models specifically for wood, they are all made exclusively stationary (see “Type”) - this is one of the key differences from similar tools for metal (another difference is the design features of the blade itself).

— Tape for metal. Band saw designed for working on metal. In addition to the design features of the tape itself, they differ from wood models (see above) in that this type of saw can be made both stationary and portable. At the same time, hand-held band saw can be a good alternative to traditional hacksaws - although they are noticeably more expensive and heavier, and also require a power source, they have higher productivity and require virtually no effort.

- Saber. A type of saw, also called “electric hacksaw”. According to the key principle of operation, they are similar to conventional hacksaws: the blade of such a saw moves back and forth during operation. One of the key advantages of reciprocating saw is their compactness, which allows them to be used in cramped spaces where there is not enough space for a circular saw or chain saw. At the same time, replacement blades are quite universal; they are produced for different materials: wood, metal, concrete, stone. And some blades allow you to make neat cuts even in a combined material - for example, a roof that combines wood, roofing felt and metal.

— Circular (disc). The working element in such saw is a rotating rim with teeth (for wood) or a diamond abrasive coating (for stone, glass and other special materials). It allows you to make straight cuts quickly and easily, but the depth of cut is limited by the radius of the blade. Note that some types of saw described below also use a disc, but due to their specialization they are divided into separate categories. Specifically, circular saw can be either portable or stationary; the second type is usually made in the form of a table with the edge of the rim protruding above the surface - this makes it easier to work with long parts.

- Trimming. A variant of a circular saw designed for cross-sections of processed materials - boards, slabs, beams, etc. They have only a stationary structure (see “Type”), and the cutting rim can rise and fall relative to the base. On the base there is a platform with a mount for the workpiece; Many models are equipped with additional stops for long parts and/or devices for placing workpieces at an angle. When such a saw operates, the rotating rim is lowered onto the workpiece at the point of the cut, ensuring cutting; Most models allow the disc to be tilted relative to the base, for bevel cuts.

- Combined. Saws that allow two options for use - both as a miter saw and as a stationary circular saw. See above for more information about these varieties. Here we note that the combination saw resembles a miter tool, the upper moving part of which (with the motor and rim) is equipped with an additional table. Thanks to this, you can also use the saw as a stationary “circular saw” - by lowering the rim all the way and securing it in this position. The main disadvantage of such universal models is their rather high cost, which is why they are used mainly in the professional field.

- Cut-off. A specific type of miter saw, designed exclusively for working on metal - for cutting metal tubes, rods, profile elements and other parts where a large cutting length is not required. The design of such units is almost completely similar to cross-cut units, with the exception of the type of disks used and more powerful motors.

— Radial-cantilever. A specific type of miter saw. They use a cutting mechanism in the form of a rim, but it is installed not under the desktop, but above it, on a console - a special design that resembles a miniature crane. The “boom” of this crane can be rotated from side to side, and the cutting disc can be moved back and forth on it and rotated relative to the vertical. This makes the saw very maneuverable and expands its capabilities, but has a noticeable impact on its dimensions and cost.

- Petrol cutter. In fact, a gas cutter is a modification of a circular saw (see above), equipped, as the name suggests, with a gasoline engine. Such engines combine high power and autonomy; Their features are described in more detail in paragraph “Power source”. Here we note that gas cutters work well not only with wood, but also with concrete, stone and other similar materials, due to which they are widely used in construction and rescue work.

— Alligator. A peculiar modification of reciprocating saw (see the corresponding paragraph). Alligator instruments have two blades moving back and forth in antiphase: while one blade moves forward, the other moves backward. Due to this, the accuracy and safety of work significantly increases - the mutual movement of the blades reduces the risk that the saw may be pulled to the side. On the other hand, the cut is wider, and the tools themselves are more bulky, heavy and expensive than reciprocating saw.

— Portable. Hand tools designed to hold on weight during work. The main advantage of such saws, in accordance with the name, is mobility and ease of carrying from place to place. In addition, such a tool can "climb" into hard-to-reach places, as well as work with parts that cannot be brought to a stationary saw. On the other hand, portable units are more demanding on the skills of the operator, require increased caution, and are also less suitable for long-term work — holding the tool on weight for a long time can be very tiring. Portable, by definition, are all chain and reciprocating saws, as well as gas cutters and "alligators"(see "Device"); in addition, many disk units and some tape ones belong to this type.

— Stationary. Saws that have a stand and are placed on the floor, workbench or other similar surface during operation. Such tools are much larger and heavier than portable ones, they are designed to be permanently in one place and do not require frequent carrying. On the other hand, stationary saws are more convenient to use than portable saws, they are less tiring and more accurate. In addition, the design of such units may include stops, rulers and other devices for additional convenience of sawing (including cutting at an angle). Stationary are all miter, cutting, combined and radial-cantilever saws (see "Device"), as well...as many circular and most band saws.

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.

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.

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 speed of rotation of the engine in a saw with an internal combustion engine (see "Power") with no load on the blade and with the speed controller fully released (set to minimum). Theoretically, the lower the idle speed, the lower the fuel consumption without load (ceteris paribus); however, the difference between modern chainsaws is usually so insignificant that this parameter is more of a reference than a real practical value.

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 diameter of the mounting hole for which the blade holder in the saw of the corresponding design is designed (see "Device"). In fact, this paragraph indicates the diameter of the axis on which the disk is installed — this size should correspond to the hole in the disk itself.

Note that some models of saws allow the installation of discs with larger holes than indicated in the specifications — when using an adapter sleeve. The main thing is that the own diameter of the disk does not exceed the values \u200b\u200ballowed for this model (see "Tyre / disk diameter"). Popular sizes include 20mm, 25mm and 30mm.