Grinder or ushm: what is it, types, explanation and how to choose

Angle grinding machines (angle grinders) come in different sizes. The larger the grinder, the larger the diameter of the cutting wheel you can put on it. But large devices also have a lot of weight. It is difficult to work with such a tool at heights and impossible to get into hard-to-reach places. Another thing is a mini-grinder: it is lightweight, easy to use, more economical, and most importantly, it can perform the same range of work as a large one.

Among the smallest specimens there are models whose cutting wheel reaches 70 mm in diameter. Such miniature equipment can even perform jewelry operations.

When purchasing any model of an angle grinder, both large and small, you must not forget that they are all dangerous tools with which you need to be extremely careful: negligence can lead to irreparable damage!

Bulgarian or ushm decoding and what it is

Among both home tools and at any enterprise there is almost always an angle grinder, meaning an angle grinder. The second, more common name is “grinder”.

The grinder is intended for cutting and cleaning surfaces made of metal, concrete, tiles, bricks and other hard materials, and sanding wood. Areas of application: construction, home renovation, mechanical engineering and metalworking, automotive services. There are cases when experienced specialists can work with it for purposes other than its intended purpose - cutting boards or slate, but in terms of safety precautions such work is not reliable. Grinding and metal cutting work is optimal.

The low cost, good maintainability, high versatility and wide capabilities of the angle grinder have made it one of the most common tools.

The main purpose of a mini angle grinder

Using a small angle grinder (except for micro angle grinders), you can perform the entire list of operations available for a large tool. The difference here is that because of its lower power, a small device is less effective for larger loads, such as cutting thick steel. Purpose of mini-angle grinder:

1. Cutting operations. A grinder can be used to cut steel, other metal, concrete, asbestos, slate, and ceramic tiles.
2. Peeling operations. The small device is convenient for cleaning surfaces from rust, oxides, and old paint on metal structures and wood.
3. Gating operations. You can make grooves for electrical wires and other communications, remove old grout from the seams of ceramic tiles.
4. Grinding operations. A grinder can be used to grind and polish surfaces.
5. Sharpening operations. The small angle grinder is ideal for sharpening household cutting and stabbing tools.

Why is the tool called an angle grinder?

An angle grinder is an angle grinder; the working force is applied at an angle to the body. The name “angular” is based on the design of the device: the entire device is placed in a housing, the working element of which extends at a right angle. This is the difference from straight grinding.

The angle connection imposes some limitations on functionality, so the straight grinder is more versatile. The grinder can only perform cutting, grinding and creating a polished surface; her colleague can also perform drilling and engraving.

The body is cylindrical and contains an electric motor. The motor shaft is connected to the working axis through a gear drive. The output torque is directly dependent on the power and diameter of the disk.

The external design consists of a handle with control buttons on the body itself and a screw-on handle for holding, as well as a power cord. The handle is screwed into the head of the tool without additional devices.

Metabo W 650-125: German brand, Chinese assembly

This is an example of good factory assembly, even though it is from China. Strong plastic, no gaps or cracks. And if you take into account the ergonomically consistent shape of the body, you are left with only pleasant impressions of the machine. It fits comfortably in your hands. If you get used to it, you can easily work alone. Even though the weight is a little more than 1.5 kg, the hand does not get tired quickly.

With constant loads of 40 minutes in a row, the angle grinder does not overheat. It is quite powerful (650 W), but kind and obedient. And revvy, produces 11,000 rpm at idle. It works smoothly, without jerking, although there is no soft start. Vibration is not felt, no matter what discs you have to tinker with. And standard circles, discs and attachments, which are sold in any hardware store, are suitable for the Metabo W 650-125, as long as the diameter of the mounting hole is 22.23 mm.

The cord is of high quality: a bit harsh, but this inspires confidence. The length is 2.5 meters, as they say, neither short nor long, but you can always use an extension cord if necessary.

Against the backdrop of pure honey, this angle grinder has its own fly in the ointment. More precisely, not one, but four.

1. The on/off button is not well thought out. Over time, it becomes clogged with dust and other debris, so it does not respond to touch. Users write that they had to unplug the cord from the outlet to stop the machine. So you will have to sometimes clean the grooves of this button.
2. It will not be possible to place the casing parallel to the angle grinder due to the fact that it is hampered by the fastening. It rests on the body, so you need to adapt to this feature.
3. This angle grinder does not have a soft start. When you turn it on, you have to be on guard, because it jerks and immediately starts thrashing at crazy speeds. Although you quickly get used to it.
4. No SDS quick release nut. If only I could work more pleasantly.

Lesser known names of ushm

There are other names for angle grinders.

The device was invented in Germany back in the 1920s. Years later, in 1954, the same inventors released production samples.

The unofficial “grinder” came into use after its appearance in the USSR in the early 1970s. Then in Bulgaria they began to produce devices that were supplied to neighbors for construction work. By the way, nowhere in the world except in the countries of the former USSR is this word used in relation to the Bulgarian. In our country it is also called as follows:

1. “monkey” - there were rumors among working people that constant use of the machine lengthens the arms and makes a person look like this animal - as a result, the joke was almost forgotten;
2. “turbine” - the sound produced by an angle grinder is very similar to that produced by a real turbine or car;
3. “Fortune” - when the first manual machines with this name appeared in the USSR. The working masses appreciated their convenience, the name became a household word.

Metabo WEV 15-125 Quick (600468000): cuts metal like clockwork

German assembly - and that says it all. The grinder is heavy (2.5 kg), however, given its power (1550 W) and wide functionality, you turn a blind eye to the weight. It starts smoothly and this feature protects the motor from overloads. For convenience, you can turn the gearbox up with the power button.

Metabo WEV 15-125 Quick is the best grinder for those who haven’t gotten the hang of it. It is not a cheap device for training, but it forgives mistakes, compensating for it with its security systems.

Three features of this tool:

• the protective cover can be installed and adjusted manually, without tools;
• You can change discs much faster using a quick-release nut;
• Vibration handle and overheating protection are provided.

Types of grinders (ushm)

There are a whole range of varieties and types of grinders. Some are better suited for certain conditions, while some can do more than just cut metal, and the technical characteristics can vary greatly. There are varieties that are strictly connected to a compressed air network, and there are mobile ones - battery-powered or motorized (options such as moto are not shown - they are too exotic). For the job, you can choose a powerful saw or even a long drill. The main types and types can be identified as follows.

Mini grinder

The small (mini) grinder is a small version with a light weight. Its distinctive features are work with a circle with a diameter of up to 125 mm and the absence of a side handle.

The main purpose is operations in confined spaces and hard-to-reach places. The low weight does not tire the hand, so working with the mini machine lasts longer and is more efficient.

Due to the low power (up to 1 kW), the number of revolutions is not significant, so the design does not have a gearbox. Thanks to this same feature, the vibration is weak, so the work is more accurate. This makes it easy to polish.

The functionality of the machine is enhanced by the fact that the body itself is a handle: by setting the button to permanent operation, you can very easily grind surfaces and simultaneously hold or perform related operations. Due to its small size, it is convenient to perform gating at a considerable height.

Big grinder

The large grinder is a regular version with dimensions and power that allow you to work with a circle with a diameter of up to 230 mm and requires two-handed operation.

The most common type, equipped with a protective shield, a side handle (installation in several positions is possible) and requires removal of the working disk with a special key. The work is done in the largest circles. Therefore, depending on the manufacturer and configuration, there may be built-in speed control, and the gearbox is made of durable materials. Power is supplied from the general power supply, so when choosing, you should pay attention to the length of the cord. Regardless of power supply, cutting with water supply is possible. There are also vacuum cleaners for grinders.

Unlike the small one, it is often used as a wall chaser. High power when cutting allows you to quickly obtain a high-quality result - the grooves will be even. However, it should be borne in mind that the mass of the tool can be considerable, so it will not be easy to ditch at high altitudes. As for the diameter of the circle, with its large size, cutting the wall can stop in front of the inner corner near the floor.

When cutting rolled products with such a powerful machine, it is optimal to place the metal in a stand - on racks or in a miter box.

Wireless grinder

The wireless one is powered by a battery, so its dimensions and weight speak for themselves. Working with such a machine has maximum mobility and does not require meters of extension cord.

The working part is not fundamentally different from the usual one, but the rear part is significantly different: there are connectors for attaching and connecting the battery. The kit fits into a case.

There are also changes in the motor: power from the mains is suitable for an AC motor, and the battery motor is suitable for DC. The difference is in power; a DC motor produces less power for an angle grinder.

In this regard, the purpose of a cordless machine is the accuracy of the operation performed. It is most effective to accurately and quickly cut fairly durable materials - from granite to cast iron (even such small models are enough to cut a cast iron battery). Portability makes it best for car repairs.

Grinder straight

A straight angle grinder is different in appearance: the working body is a continuation of the body, usually there is no additional handle. The work can be done with one hand. The second hand is used to correct or hold material, or to stay in space under difficult conditions.

Its purpose is to work in hard-to-reach and miniature places and an extended list of operations. For this purpose, an extension cord or an adapter for an angle grinder is supplied in the kit or separately.

The design is convenient for polishing work. To treat the surface, you can use not only discs, but also cylindrical and conical nozzles of abrasive and petal types (to remove the height of the concrete floor in the corners), drills (this way you get a grinder-drill). Adapters are available for attachments. The end installation of the circle is convenient in its own way.

The number of revolutions per minute is up to 30,000 thousand. Usually a soft start system and overload protection are installed.

Ushm pneumatic

The operation of a pneumatic angle grinder is based on the supply of air under pressure to the working part. To do this, connect to the compressed air system - there is a special connector for this purpose.

The compressed air is started by pressing the trigger. After entering the internal cavity of the machine, the air spins the rotor, which in turn, through the gearbox, creates rotation of the working circles.

Like other options, the pneumatic angle grinder comes with a protective shield and an additional handle. Compared to others, it has a longer service life and quite high power. Such a tool can be used in a polluted environment. The housing is sealed and durable due to pressure work.

However, due to air escaping from the case, it is often impossible to work without dust. However, it is possible to install a dust removal system (as on other models). Polishing is often done to prevent too much dust. And the air suspension accelerates from the supply hose.

Brushless grinder

Like any other electrical device, an angle grinder includes such an element as brushes - removable sliding-type electrical contacts. The design of the brushes is developed, but quite unified (although each manufacturer produces their own).

As a mechanical element operating under dynamic conditions with constant friction, brushes often fail. The brushless motor is the next step in the development of electrical engineering. It requires less repair due to the absence of brushes, makes less noise and does not produce sparks. This allows us to consider this model more fireproof. A brushless angle grinder works quietly in very dusty air - it has no equal in repairs and construction. The question is how to grind a concrete floor (if it is not possible to install a dust extractor).

The price is a little more expensive than the classic model, but the advantages outweigh the cost of regularly replacing the brushes.

Disk selection rules

When choosing a grinding machine, be sure to take into account that the conditions for replacing discs are created as optimal as possible. Some cutting models often come with wrenches. And some contain special nuts, with which you can easily replace the disk.

As for the disks themselves , when choosing, you need to decide on the purposes of their use. Key parameters are:

• thickness;
• diameter.

The smallest grinding machines have discs with a diameter of 125 mm, and the largest - 250 mm, respectively. But keep in mind that these indicators are not the limits for a particular tool, since larger discs can be used on professional tools.

You need to pay attention to the diameter of the disk because it determines the thickness of the workpiece. As well as the maximum cutting depth.

If you need a tool for cutting metal products , then it is better to use cutting discs. The thickness of household models is 1−1.2 mm. Industrial models can have a value of up to 2.5 mm.

The correct size disc is designed to create optimal conditions for the craftsman, since it will not need to apply much pressure to the angle grinder. As a result, the cut will be neat and done without difficulty. If you need a tool for curly carving on thin metal, then the discs should be of the minimum size or take old, used ones.

Some craftsmen believe that it is better to use diamond blades for cutting metal, but this is not true. If such a disk is used for metal, it can get stuck in it, and then it will be problematic to use it for its intended purpose.

How to choose an angle grinder or an angle grinder

To select the right angle grinder, you should consider the following parameters and capabilities:

1. Power - it all depends on the scope of application: for home a range from 600 to 900 W will be enough, for professionals 1500 W is optimal;
2. A smooth start will eliminate jerks when starting, which is good when continuing to work in the old cut, and your hands will get less tired;
3. Speed ​​in revolutions: the ideal option is with a speed setting, but for fixed revolutions up to 12,000 per minute is enough for disk diameters up to 125 mm and up to 7,000 for 180 mm; It is important to remember that circles of different diameters move at different angular speeds at the same rotation speed - there is a limit at which the destruction of the disk begins (usually 80 m/s), so it is impossible to install a circle that is too large on a small model;
4. The presence of a side handle with installation in different positions;
5. The locking button will help with long-term work (such as stripping);
6. The presence of dust protection (when working with dust-emitting materials, the closed gearbox and varnish coating of the stator with the rotor are useful), a dust removal system (when working with concrete, an angle grinder with a vacuum cleaner helps, for which there may be a connection point);
7. The ability to replace a disk without a key speaks for itself if you have to use it often;
8. Operating mode - the break period plays a role due to the need for the angle grinder to cool down under heavy load or long-term operation (if the housing or gearbox overheats, it may fail).

The main features of small grinders

A small grinder has its own characteristics that make it an indispensable tool in solving a number of construction and repair problems:

1. Has light weight. This feature allows you to work on weight for a long time without getting tired.
2. It has compact dimensions, which allows the device to work in places where it is difficult to reach with more bulky equipment.
3. You can work without using an additional handle: thanks to the small diameter of the body, the small grinder can be grasped with just one hand and cleaned the surface. This is very convenient if you have to hold on with one hand and work with the other.
4. There are battery-type devices, which gives even more freedom in using the tool.
5. Small grinders have little power. This eliminates the possibility of strong vibration during operation and makes it possible to carry out more precise processing.

It is strictly forbidden to perform cutting operations on an angle grinder if you have to hold it with one hand. The speed of a small tool is high enough that if it jams, it can be pulled out of your hands and cause serious injury to the operator!

The main purpose of the tool

During the Soviet years, the most popular scientific journal was Science and Life. The reason for this was the sections “Crossword with fragments” and “Little tricks” . The last section was filled with letters from readers who were ready to share their experience of inventing in non-standard solutions to everyday problems, among which electricity issues occupied a significant share.

In those years, electric cutting machines were not widely sold, and therefore no mention of grinders can be found in “Little Tricks”. After all, the industrial grinders, or “fortunes,” that already existed then, powered by compressed air, were not used in an apartment or garage. In addition, their design flaw in the form of a heavy pneumatic hose and the presence of a compressor with a receiver nullified the possibility of using it in everyday life.

But now the choice of cutting tools is widest, and its areas of application meet all the needs of modern builders. The main purposes of the grinder:

• 
  trimming various parts or structures;

• removal of part of the material in the body of the product structure, gating;
• stripping unprepared surfaces of parts and assemblies before further work with them, including deburring after cutting;
• surface grinding using special wheels, including dulling of sharp edges;
• tool sharpening (using diamond wheels, cutters, etc.).

Device

As in the case of large-format models, mini-grinders can be classified based on the following characteristics:

• engine power;
• spindle speed indicators;
• ergonomics;
• weight and dimensions.

And although for each buyer it is power that should be the determining guideline when choosing, nevertheless, for small models of this tool, other characteristics given in the last paragraphs of this list are also quite relevant.

What sets the mini-grinder apart from most other tools in this class is its small size. In size it is comparable to two or three electric toothbrushes . The package of such equipment usually contains all the necessary accessories, from grinding wheels to other additional devices that expand the functionality of this tool.

Among the advantages of this equipment, it should be highlighted that it can be used to solve various problems where it is important to ensure jewelry precision. But this is not surprising, since this tool was developed precisely for these purposes. In addition to this, after purchasing an angle grinder, it will be quite easy for you to process small areas. This quality will be valuable to you especially in cases where other alternative tools cannot cope with a similar task.