Real power
Power delivered during work directly to the working nozzle. High power, on the one hand, contributes to performance, on the other hand, it significantly affects the dimensions, weight and price. Therefore, it is worth choosing a tool for this parameter, taking into account the specifics of the planned work; recommendations on specific power values for different types of work can be found in special sources.
Power consumption
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.
Rotation speed
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.
Oscillation speed
The frequency of vibration of the working attachment, which is capable of providing a grinder of the appropriate design (a classic example is vibration, see "Type"). If the device has an oscillation frequency adjustment, this paragraph gives the range of such adjustment, from minimum to maximum.
A higher frequency (with the same amplitude — see below) improves overall performance, especially when working with hard, stubborn materials, and also contributes to efficiency in delicate finishing (such as polishing). In turn, a lower frequency reduces the likelihood of making a mistake by removing an excessive amount of material. There are also more specific points related to this parameter; them, as well as recommendations for choosing the frequency for different jobs, materials and types of sanding sheets, can be found in special sources. Here, we note that individual sanding sheets may have their own limitations or recommendations regarding the operating frequency.
Oscillation amplitude
The amplitude of oscillations made during the operation of the nozzle of an eccentric,
vibration or delta grinding type machine (see above). Along with the frequency (see above), it is one of the most important indicators of such machines. Higher
amplitude provides more intensive processing, which has a positive effect on performance; on the other hand, for delicate work, it is desirable to have
a small oscillation amplitude(less than
2 mm).
Tape/sheet length
The length of the belt or sheet for which the grinder is designed.
Working nozzles in the form of sheets are used in units with a vibrational principle of operation, in the form of tapes — respectively, in tape ones (for more details on both, see "Type"). Anyway, this paragraph does not indicate the working length of the tape / sheet (that is, the length of the surface adjacent to the material being processed), but the total — that is, the size of the nozzle itself. This size in itself determines only the compatibility of the grinder with certain sheets / tapes. At the same time, clamp-like fastenings (see "Sheet fastening"), used in most classic vibrating instruments, often allow you to install sheets of slightly longer lengths than indicated in the specifications. Hook-and-loop models (mostly delta sanders) technically accept both longer and shorter sheets, although in fact this is not recommended at best. But in tape tools, the length of the tape must exactly match the parameter specified in this paragraph — even a slight deviation can lead to incompatibility.
As for the working length of the tape / sheet, it inevitably turns out to be less than the total (for sheets — not much, for tapes — quite significantly). However a longer tape/sheet often has a greater working length; however, with the same general dimensions of the nozzle, its working size in different tools may be different; it is indicated in the item "Sole Size" (see below).
Belt / sheet width
The width of the belt or sheet for which the grinder is designed.
Working nozzles in the form of sheets are used in units with a vibrational principle of operation, in the form of tapes — respectively, in tape ones (for more details on both, see "Type"). Anyway, this paragraph does not indicate the working width of the tape / sheet (that is, the width of the surface adjacent to the material being processed), but the total — that is, the size of the nozzle itself. This size in itself determines only the compatibility of the grinder with certain sheets / tapes. At the same time, clamp-like fasteners (see “Sheet fastening”), used in most classic vibrating instruments, usually fix the sheet only in front and behind, so that in such instruments the restrictions on width are not as strict as, for example, on length: the sheet may be somewhat wider, and somewhat narrower than the nominal size. However, such possibilities should be clarified separately, and for a full guarantee it is better to clarify whether a particular machine allows deviations in width. The situation is similar with delta sanders, where Hook-and-loop is traditionally used: a discrepancy in width technically does not prevent the installation of a nozzle, but not all models allow this. As for the band tools, they may allow the installation of a narrower band — but not a wider one.
As for the working width, it, usually, corresponds to the general one, or (in some vibration models) differs slightl...y from it. Anyway, the working width is given under Sole Size (see below).
Pad size
The size of the sole provided in the tool.
This parameter is indicated for two types of grinders — most models with a vibrational principle of operation (namely, for vibration and delta grinders, as well as multifunctional ones), as well as belt units. For more information about both, see "Type", here we note that the sole as such is only available in vibrating tools — in tape tools, we are talking about the size of the section of the tape that is in direct contact with the material. Simply put, the size of the sole is the size of the working surface of the machine.
The larger the size of this surface, the more performant the machine, the better it is suitable for large volumes of work. And tape models, we recall, are used mainly for processing oblong parts and during operation they are usually located across such a part; so that for such machines it is highly desirable that the length of the tape be not less than the width of the surface to be treated — otherwise, accurate processing can be quite difficult. On the other hand, a large sole inevitably affects the dimensions, weight, and most often the cost of the tool, besides, it can make it difficult to use in cramped conditions. Yes, and consumables for such soles (sheets, tapes) require larger ones — and, accordingly, more expensive. So when choosing according to this indicator, it is worth considering the features of the intended application; if you wish, you can refer to special sources for detailed r...ecommendations on this matter.
Also note that for multifunctional models (see "Type") in this paragraph, several options are most often given — for each specific sole. However, there are models where only one set of sizes is indicated. This can either mean that both main vibration nozzles (rectangular and triangular) have the same dimensions in length and width — or that the data is indicated for a non-removable triangular sole, on which a larger rectangular one is put on if necessary. Such details can often be clarified directly from the photographs of the goods, in extreme cases — from the manufacturer's documentation.
Sheet fixing
The method of fastening the sanding sheet, provided for in a grinder with a vibrational principle of operation (vibration, delta sanding, multifunctional — see "Type").
— Clamps. Usually, this option provides a pair of clips located in the front and back of the sole. It can only be implemented in rectangular soles — for triangular soles used in delta grinding models, such devices are not suitable. Clips are somewhat less convenient than hook-and-loop, they require both more steps to secure the sheet, and more attention during these steps. On the other hand, this type of fastening is much more reliable than Hook-and-loop, it perfectly fixes the sheets and can be used even in the most powerful machines that work with high loads. In addition, compared to Hook-and-loop, clips are as versatile as possible (from the inside, the sanding sheet can have any surface — the main thing is that it fits in size) and more durable (practically do not lose their properties over time). And thanks to the durable materials that are usually used in the design, the likelihood of breakage of such a latch is minimal. Therefore, it is this option that is used in the vast majority of classic vibration machines — with rectangular soles.
— Hook-and-loop. Fastening according to the principle of a classic Hook-and-loop fastener: the sole has a surface with a set of microscopic hooks, and the underside of the sanding sheet is made of felt, for the fibers of which the hooks are hooked. Th...e main advantage of this option is that it has no restrictions on the form. So it is Hook-and-loop that is used in all modern delta sanders and multifunctional models (see "Type"), although in the second case they can be combined with clips. In addition, “sticking” and “unsticking” sheets on such a sole is easier and faster than changing nozzles in clamps. On the other hand, the reliability of fixation is somewhat lower than that of clamps; and over time, the effectiveness of Hook-and-loop can be further reduced due to wear on the hooks (the felt surface of sanding sheets also wears out a lot, but the working side of the sheet usually becomes unusable much earlier than the fastening one). In addition, this method of fastening is only suitable for a certain type of sheets — with a reverse surface for Hook-and-loop. In light of all this, this option is extremely rare in vibratory machines with rectangular soles — more often a combination with clamps is used, and most of these models use only clamps. Although in some situations, Hook-and-loop may be the best option for such a tool — for example, if high loads are not expected, and it is desirable to change the sheets without unnecessary delays.
— Hook-and-loop and clips. A combination of both options described above in one tool. The specific features of this combination directly depend on the type of grinder. So, in multifunctional models, different types of latches are usually provided on different removable soles: clips on a rectangular one, Hook-and-loop on a “delta”. Thus, each version of the working surface uses the method of fastening that is optimally suitable for it. And in vibration models, this design makes the machine as versatile as possible, allowing you to use sheets with it for both Hook-and-loop and clips.
