Comparison DeWALT D28136KD vs DeWALT D28135

The power consumed by the grinder during operation. Usually more than the output (useful) power (see above) due to losses during the conversion of energy from electrical to mechanical. However, the general patterns in this case are the same: a more powerful tool, on the one hand, is usually more performant, on the other hand, it is heavier, larger and more expensive. In addition, the total electricity consumption depends on this indicator; however, grinders, even the most powerful ones, consume relatively little energy, and difficulties can arise only when connecting a high-performance professional tool to weak electrical wiring.

Note that it is much easier to determine the consumed power than the useful one; therefore, only this parameter is often indicated in the characteristics, without specifying the useful power. In general, it is quite possible to compare grinders of the same type using it (see above): a modern tool has approximately the same efficiency, and in most cases the useful power values bare related in the same way as the consumed values.

The speed of rotation of the working attachment, which is capable of providing a grinder of the appropriate design (for example, angle — see "Type"). If the device has speed control, this paragraph shows the range of such adjustment, from minimum to maximum.

It makes sense to compare by this parameter units belonging to the same type and having the same maximum diameter of the disk (or other working nozzle). The latter is due to the fact that the larger the disk, the faster its edge moves (at the same speed); i.e. a larger diameter requires less RPM for the same performance/efficiency. In general, when comparing different models, the following should be taken into account. The higher rotation speed is well suited for large volumes of work (because it improves productivity) as well as for fine polishing with “delicate” nozzles. A lower setting, in turn, improves accuracy (reduces the chance of removing excess material), as well as provides more torque and allows you to more effectively deal with hard, stubborn materials. More detailed recommendations for different types of work and different nozzle diameters can be found in special sources; here we note that an increase in the rotation speed, usually, affects the cost of the machine compared to analogues (since this requires a more powerful engine). In addition, discs and other attachments may have maximum RPM limits.

Soft start ensures a smooth motor acceleration of the grinder with relatively low acceleration. This is achieved by limiting the start-up current. Soft start performs two functions: it prevents sudden jerks of the tool, reducing the risk of dropping it, and also decreases the load on the electrical network, helping to avoid significant voltage spikes.

The ability to lock the power button prevents accidental presses. Accidental Activation Protection allows safely transporting the switched-off tool from place to place during work breaks without fear of unintentionally turning it on. This feature is also handy when there are small children around. In some models, protection can also be activated when the power is cut off (for example, network failures) — thanks to this, when the power is restored (which can occur at the most unexpected moment), the tool will not start operating without a user command.

A safety system that turns off the tool when there is a critical increase in load. The specific operation method of the electronic motor protection can vary. For example, in some models, it shuts off the motor when there is a sharp increase in load on the working attachment, such as when the disk jams in the material; this helps avoid sharp jerks of the tool, breakage, disk destruction, and other unpleasant consequences. In other models, the protection responds to overheating or a critical excess of current strength. There are also tools that combine both options.

Kickback protection is a set of solutions that reduces tool jerking and twisting when the disc binds in material (concrete, metal, stone). It is implemented in two ways: mechanical safety clutch and electronic systems. The clutch (for example, S-automatic from Metabo, SJS/SJS II from Makita) disengages the drive when the torque increases sharply, saving the gearbox and wrist—the tool does not "shoot" out of hands and does not tear gear teeth. Electronics (Bosch KickBack Control, DeWalt E-CLUTCH, Hilti ATC, HiKOKI/Hitachi RFC, Milwaukee AUTOSTOP, Makita AFT) monitors current and accelerations, instantly shutting off the motor and often, in conjunction with a brake, quickly stopping the disc. In comparison: the clutch works even without power, providing a smooth "slip," but the disc continues to rotate briefly; electronic protection shuts down the motor "to zero," but requires functioning electronics and sometimes a restart. In practice, this is important during grooving and cutting of reinforcement, when the risk of binding increases: with protection, the operator controls the tool, reduces dangerous jerks, and protects the gearbox—whether it is a compact 125-mm cordless grinder or a powerful 230-mm corded model.

— Speed Controller. The ability to limit the engine's maximum speed. Essentially, this function is a smooth speed adjustment; it's convenient when full speed isn't required — for example, in delicate tasks where precision is more important than performance. Note that this feature is found in all types of sanders — including those with a vibrational or belt operation (see "Type"): even in these machines, the vibration frequency or belt speed is determined by the engine's rotations.

— Speed Maintenance. The ability to maintain a set number of rotations regardless of the load on the working attachment. This function is implemented through automation, which adjusts the engine's power accordingly — increasing it under more load and decreasing it under lighter load. Constant rotation speed positively affects both the quality of processing and the lifespan of the working attachments and the tool itself.

— Brushless Motor. The presence of a brushless motor in an electric sander (see "Power Source"). These motors are considered more advanced than traditional brushed motors: they are more energy-efficient, quieter, and do not spark, which can be crucial in fire-hazardous environments. The main downside of brushless motors is their high cost.

— Lighting. This feature is undoubtedly desirable when working in lo...w-light conditions. However, it can also be useful in bright external light: the work area often ends up in shadow (e.g., from the tool itself), making it difficult to work without special lighting.

— Display. A built-in display that can show various information about the device's operation and status. Such a screen provides additional convenience and clarity, but overall, it is quite a specific feature that is rarely found in modern power tools.

— Smartphone Synchronization. The ability to connect the tool to a smartphone or other gadget (like a tablet) via Wi-Fi or Bluetooth. Such a connection is usually used for adjusting work parameters; it's often more convenient to do this through a mobile app than through the controls on the tool itself.

— Rotating Main Handle. The ability to rotate the main handle of the sander around the longitudinal axis. This feature is mainly found in angle models (see "Type") — it provides extra convenience, allowing you to adjust the handle's position according to the situation. This is important for working in unusual positions and hard-to-reach areas.

— Keyless Disc Replacement. The ability to change discs in a sander (usually angle, see "Type") without using keys and other additional tools. The convenience of this feature is clear: you don't need to constantly have a key on hand, keep track of it not getting lost, etc. However, keyless mounting is considered somewhat less reliable than keyed mounting, so it's rarely found in heavy-duty professional models.

— X-LOCK Mounting System. An advanced mounting system for the working attachment, used in some angle machines (see "Type") — predominantly made by Bosch and Makita. This system is somewhat more expensive than traditional 22-millimeter mounting using a nut or washer, but it has several advantages. Firstly, X-LOCK provides the simplest and quickest installation: no need to fuss with additional parts or tools, just place the disc on the spindle and press until it clicks; for removing the attachment, just press a button that disables the lock. Secondly, you can only install the attachment in one correct way relative to the tool — the design of the mounting disallows any other way. The main disadvantage of machines with this system is their incompatibility with cheaper and more common 22 mm standard discs; fittings under X-LOCK are not yet available in every hardware store.

— Collet Chuck. A specially designed chuck used in straight grinders (see "Type"). The grip of such a chuck consists of several elastic petals (usually 2-3) that compress when tightened, securing the working attachment. The main advantages of collets are the speed and convenience in changing attachments, simplicity of design, and low cost.

— Coolant Supply (Coolant). The ability to supply coolant to the work area. This function is mainly found in machines for stone and concrete (see "Type"), as water cooling is most relevant for these materials: it not only prevents overheating but also reduces dust formation. The machine provides a nozzle directed at the working attachment and a fitting for connecting to a water hose.

— Dust Collector Connection. The ability to connect a dust collection container to the tool for collecting dust and other debris generated during operation. Such a container may come with the machine, but this is not guaranteed, and this point should be clarified separately. In any case, a dust collector, while not providing 100% protection against debris, significantly reduces it and simplifies cleanup afterward. Dust collectors can be either reusable or disposable.

— Additional Handle. A separate handle for the second hand. In theory, such equipment may make the tool more comfortable to hold with both hands. However, in practice, the absence of an additional handle is often not critical: many tools without it are either designed for one-handed use (like some straight grinders, see "Type") or have other attachments for the second hand (such as a protrusion on the body). So, to answer whether you need an additional handle, you should consider the type and size of the grinder, as well as the specifics of the intended projects. Note also that by default, such a handle is designed for right-handed use, and the possibility of using it in left-handed operation needs to be clarified separately.

— 3-Position Additional Handle. An additional handle installed on a detachable mount and having three installation options: on the left (traditional option for right-handed use), on the right (for left-handed use), and on top (for specific cases — situations when you need to periodically change grip, work in hard-to-reach places, etc.). This function provides extended possibilities for tool customization according to personal preferences. It is mainly found in angular models (see "Type").

— Charger (C). A device for charging the battery in a grinder with the appropriate power type (see "Power Source"). This section usually specifies...the specific model of the charger. Having a "charger" included relieves you from the need to search and purchase it separately; moreover, such a charger is optimally suited at least to the "native" battery, and often to other compatible batteries. The details on the model will be useful primarily in case the included charger is lost or fails, and you have to buy the same or a similar one instead. Moreover, knowing the model of the charger allows you to find detailed data about it and assess the characteristics and features (compatibility with various batteries, additional functions, etc.). At the same time, the configuration "without charger" is also quite popular — see below.

— Without Charger. This feature is indicated exclusively for battery models (machines with other power types — see "Power Source" — by definition do not have a charger, so this point does not need to be clarified for them). The meaning of such a configuration is that modern grinders most often use standard batteries, which also fit other power tools of the same brand and are thus designed for standard "chargers." Thus, if there is already a battery tool "in the household" — the charger for it may turn out to be suitable for the grinder, and you will not need to pay extra for a second copy of the charger. And even if there is no charger available — it can usually be purchased separately without much difficulty (and some tools even allow you to choose the most suitable model of such a device from several options).

— Case / Bag included. The presence of a case or bag for storing and transporting the tool in the supply kit. The case is a suitcase made of durable material and usually has space not only for the grinder itself but also for working tips and other additional accessories. The bag is soft, allowing it to be compactly folded when not needed. Check the availability of a case or bag directly before purchase.

— Dust Collector. A container for collecting dust and other contaminants generated during work. See "Additional — Dust Collector Connection" for more details.

— Extension Pole. A long pole significantly expands the "radius of operation" of the tool: with such equipment, you can reach greater heights, process a large area without moving the platform or other stand, etc. Such capabilities are mainly relevant when processing walls, so the vast majority of grinders with extension poles included pertain to wall sanders (see "Type").

Approximate noise level generated by the grinder during operation. Note that this indicator is quite approximate, because. actual "loudness" can vary markedly depending on the type and shape of the material being processed, the surface it is placed on, and other circumstances. In addition, different manufacturers may use different measurement methods. Nevertheless, this indicator makes it possible to assess how comfortable this or that model is in operation and whether special hearing protection is required.

The most “quiet” modern grinders give out about 65 dB — this is comparable to loud speech at a distance of 1 m; in the loudest, the noise level reaches 107 dB — this is the volume of an industrial workshop.