Comparison Pro-Craft PBG-400 75 mm / 400 W

230 V

vs Stal T 1540 150 mm / 400 W

230 V

Type, in other words, the general purpose of the machine.

— Sharpening. In accordance with the name, the main purpose of such units is to sharpen the cutting edges of various tools — from knives, chisels, etc. to saw blades and chains of mechanical saws (for more details, see "Sharpening"). Such processing is carried out due to the rotation of the abrasive disc. The traditional, familiar to many grinding machine (grindstone) has two discs on the sides of the casing with the engine; however, there are often models that differ in design (especially among specialized units, for example, for sharpening chains).

— Grinding. Grinding in the general sense is called all machines for grinding — semi-finishing and finishing of various surfaces. However, only aggregates that are not related to surface grinding are included in this category (for the latter, see below). Such machines can use different types of work items. One of the most popular options is a sanding belt mounted on two pulleys and moving due to their rotation; such a tape can be located both horizontally and vertically (“on the edge”). Another common type of work item is a disk on which sanding paper is attached. At the same time, unlike a grinding machine, the role of the working surface is played not by the edge of the disk, but by the round surface itself; this, in particular, allows you to vary the intensity of processing by moving...the workpiece closer to the centre of the circle (where the speed of movement is lower) or vice versa. There are also combined models — for two rotation modules (see below), combining both types of work items. A separate category are spindle grinders working with sleeves (see "Working element").

— Grinding and grinding. Models that combine the capabilities of grinding and grinding machines (see above). Usually, such a unit is similar to a classic grindstone with two rotation modules, in which a sanding belt or brush is installed instead of one of the discs. Thus, both sharpening and grinding can be performed on one machine. The downside of this versatility is that both in terms of grinding and grinding capabilities, such machines are inferior to specialized models. Therefore, this option is designed mainly for situations where versatility is more important than advanced functionality.

— Grinding and polishing. Machines designed both for sharpening tools and for polishing — fine finishing of the surface of the material being processed, making it smooth and shiny. Polishing can be carried out according to the same principle as sharpening — using a rotating disk; therefore, most often machines with a polishing function are positioned as combined grinding and polishing machines. Such units are often equipped with an engraver on a flexible shaft (see below). Note that they are usually somewhat smaller than "pure" grinders, use smaller discs and are less suitable for rough work.

— Polishing. This type of machine tool is similar in design to the grinding and polishing machines described above; the key difference is that the polishers only use smooth polishing pads, and are not designed for abrasive sharpening tips (even if it is technically possible to install such a sharpening tip). Such units are less versatile than grinding and polishing units, and they do not have key advantages over them; therefore, purely polishing machines have not received much distribution.

— Surface grinding. A type of grinding machine, designed primarily for the processing of flat surfaces, including conjugated. Such aggregates are fundamentally different from the "ordinary" grinding (see above) in design and mode of operation. They use a working element in the form of an abrasive disk fixed above the desktop; this table, in turn, is fixed on a massive frame, and the workpiece on it is installed in a special fixture and moves under a rotating disk during processing. Surface grinders make it easy to process large surfaces, but they are very massive, bulky and expensive, and therefore are considered professional (and even industrial) class equipment.

Regular diameter of the disk (see "Working element") used by the machine for dry processing (see above). When grinding and polishing, usually, we are talking about the maximum diameter of the disk that can be installed on the tool — a larger nozzle will either be ineffective or not fit into the dimensions of the seat at all, but a smaller diameter disk, usually, is installed without problems (of course, if the hole diameter matches — see below). For grinding machines, the diameter of the disc corresponds to the diameter of the sanding pad, which is necessary for the full use of the disc.

The larger the regular disk — the heavier and more powerful the machine, usually, the better it can cope with complex work of a large volume. At the same time, for small everyday tasks like periodically sharpening knives or chisels, a small disc is quite enough.

The bore diameter of the dry cutting discs (see above) used by the machine. In order for the nozzle to be used normally with the machine, it must match it not only in diameter and thickness (see the relevant paragraphs), but also in the size of the mounting hole.

The thickness of the "dry" blade (see "Dry Machining") for which the machine is designed. Usually, we are talking about the maximum thickness of the disc that can fit on the seat — most models allow the use of thinner nozzles.

Note that this parameter depends on the type of sharpening (see above): working with chains and saw blades involves a small thickness of the discs, universal sharpening is the opposite. And for grinding models, the thickness of the disc is not relevant at all, even if the disc is provided in the design; see "Machine" for details.

The nominal speed of rotation of the disk for dry processing (see above), provided by the machine; for models with adjustable rotation (see below), the maximum rotation speed.

For the same disc diameter and material, a higher speed provides more intensive processing, and a slower rotation contributes to accuracy and precision. In addition, optimal speeds depend on the composition of the disc and the material being processed; detailed recommendations with specific figures for a particular situation can be found in special sources.

A separate category is grinding machines with disk-shaped working elements: in such units, the actual speed of movement of the disk surface relative to the workpiece depends on how close the contact point is to the centre of the disk.

The ability to change the speed of movement of the working element of the machine. The speed controller may have its own characteristics: in some models it is smooth, in others it is stepped, the number of steps may be different, etc. Anyway, speed control greatly expands the capabilities of the machine, allowing you to adjust the mode of operation to the specific situation.

The presence of a flexible shaft with an engraver in the design of the machine. Such a device can be described as an engraving machine connected to the machine with a flexible "wire" — however, not electricity is transmitted through this wire, but rotation from the machine's engine. Thus, by purchasing such a model, the user receives a 2 in 1 unit. At the same time, the power delivered to the engraver is often higher than that of manual models, because. the movement is provided not by the built-in compact motor, but by the heavy stationary electric motor of the machine.

This feature is found mainly in grinding and polishing models (see "Machine"), originally designed for fairly delicate work.