Disc diameter
This criterion is basic. It influences the choice of power and the required speed of the disc. You can find different discs by diameter:
- 115 and 125 mm - used for household needs. With their help, you can quite effectively remove rust or old paintwork from parts, polish, cut material no more than 50 mm thick;
- 150 mm - an intermediate version of the grinder. Often 180 mm discs are also referred to the middle class.
- 180 and 230 mm - designed for processing dense and thick products. You can easily cut through heavy concrete or brick curbs, as well as asphalt pavements. The disc itself will be quite heavy, so when cutting thin products, strong vibration will occur, which is inconvenient and unacceptable.
Disc selection rules
When choosing a grinder, be sure to take into account that the conditions for replacing discs are created as optimal as possible. Some cutting models are often equipped with wrenches. And some contain special nuts in the kit, with which you can easily replace the disc.
As for the disks themselves, then when choosing, you need to decide on the goals of their use. Key parameters are:
- thickness;
- diameter.
The smallest grinders have discs with a diameter of 125 mm, and the largest - by 250 mm, respectively. But keep in mind that these indicators are not the limits for a particular instrument, since larger discs can be used on professional instruments.
It is necessary to pay attention to the diameter of the disc for the reason that it determines the thickness of the workpiece. And also the limiting depth of the cut
If you need a tool for cutting metal products, then it is better to use cut-off wheels. The thickness of household models is 1-1.2 mm. Industrial models can be up to 2.5 mm.
The correct size disc is designed to create optimal conditions for the craftsman, as it does not need to be applied to the grinder with strong pressure. As a result, the cut will be neat and easy to complete. If you need a tool for curly carving on thin metal, then the discs should be of the minimum size, or you should take old, practical ones.
Some craftsmen believe that it is better to take diamond blades for metal cutting, but this is not the case. In the case of using such a disc for metal, it can get stuck in it, and then it will be problematic to use it for its intended purpose.
The main purpose of the tool
In Soviet times, the most popular scientific journal was Science and Life. The reason for this was the sections "Crossword with fragments" and "Little tricks". The last heading was filled with letters from readers who were ready to share their experience of invention in non-standard solutions to everyday problems, among which electricity was a significant part.
In those years, there were no electric cut-off machines in the wide sale, and therefore in the "Little Tricks" there is no mention of grinders. After all, the already existing industrial grinders, or "fortunes", working on compressed air, were not used in an apartment or in a 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 its use in everyday life.
But now the choice of cutting tools is very wide, and its scope meets all the needs of modern builders. The main purposes of the grinder:
- trimming various parts or structures;
- removal of a part of the material in the body of the product structure, slitting;
- peeling of unprepared surfaces of parts and assemblies before further work with them, including deburring after cutting;
- surface grinding with special wheels, including blunting of sharp edges;
- tool sharpening (using diamond wheels, cutters, etc.).
The main features of small grinders
The small grinder has its own characteristics that make it an indispensable tool in solving a number of construction and repair tasks:
- It is lightweight. This feature allows you to work on weight for a long time without getting tired.
- It has a compact size, which allows the device to work in places where it is difficult to approach with more bulky equipment.
- 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 the surface can be cleaned. This is very convenient if you have to hold on with one hand and work with the other.
- There are battery-type devices, which gives even more freedom in the use of the tool.
- Small grinders have little power. This eliminates the possibility of strong vibration during operation and makes it possible to carry out more accurate processing.
Device
Cutting discs of a small angle grinder are the main working element of the structure. Products differ not only in basic dimensions. They still have to match the processing material. For example, the smallest discs are required to process thin metal sheets.
This can be used to cut metal pipes, which are often found in places with difficult access. For work, constructions are convenient that do not require connection to the electrical network. Especially for these purposes, angle grinders are supplied with an autonomous energy source. It can be a lithium-ion or cadmium battery.
The absence of an electric cable adds convenience to the work. Possible size for LBM circles - 125 mm. With a mini-size tool, it is allowed to correlate both cutting, abrasive, and diamond options. Due to this variety, angle grinder successfully replaces many varieties of hand tools. The device and components of all grinders are the same. The difference lies in complementary components that carry different functions. Main details:
- starter;
- rotor;
- electric brushes.
Other unit devices:
- a clutch that prevents kickback if wheel sticking is observed;
- speed regulator;
- engine start button;
- engine overload protection system;
- a button that locks the gear in the gearbox, which is necessary in the process of removing or replacing wheels;
- attachment of the grinding wheel.
In addition to plastic cases, products can be equipped with modern reinforced polymer options. The electric motor can receive energy both from batteries and from a household network. The machine with speed control is equipped with a single-stage bevel gearbox. It is usually made of aluminum or magnesium alloy. The tool can handle wood, ceramic tiles, concrete or metal substrates. Some angle grinders are still provided with a protective casing. It protects against sparks and chips flying off during operation.
Disk turnover speed
The spindle with the disk installed on it rotates at a given speed, making a certain number of revolutions per unit of time. In existing models of grinders, this parameter can vary within 2800-11000 rpm. The size of the disc dictates the required speed limit - for larger circles the number of revolutions is required less.
For small-diameter discs up to 125 mm, the highest speed parameter is set at 10-11 thousand rpm. For wheels with a diameter of 180 mm, the limit for the number of revolutions is 8.5 thousand per minute, and for maximum discs of 230 mm - no more than 6.65 thousand revolutions.Failure to comply with this parameter can cause the disc to break and injure the operator.
The LBM marking indicates the maximum disc size that can be used, for example, 115-150 mm circles can be attached to a model with a 150 mm limitation. Therefore, it is recommended to buy more versatile angle grinders with speed control.
How to choose?
To choose the right angle grinder will help not only knowledge of their main characteristics, but also the ability to compare and analyze. The main parameter of the tool is the idle rotation speed, which indicates the power. Accordingly, powerful models have great performance.
Modern grinders are complemented by special options. On the one hand, they complicate the choice, and on the other, they simplify the processing of materials. For example, the automatic wheel lock helps eliminate unevenness in operations such as cutting or grinding. They can be caused by vibration from worn discs. The starting current limiting mode ensures the stable performance of the implement in accordance with the standard parameters of a conventional household network. Professional grinders often put a load on the network at the time of launch.
An additional handle attachment simplifies the cutting process. Without it, there is a need for strong physical pressure. Additional convenience is added by a special coating that reduces the force of vibrations. This makes it possible to process materials with high precision.
Replacing a disc is a common occurrence in working with angle grinders. Many models require a special tool for this operation. If the machine has a special nut, the procedure can be performed faster and more conveniently.
It is important to choose the right discs for the selected tool. The actual parameters for them are thickness and diameter
The basic size of discs for mini-machines is 125 mm. The possible cut depth depends on the diameter of this part. The optimum thickness is 1-1.2 mm. It is more convenient to make a neat cut with a disc of a comfortable size. For example, for curly operations, specialists use products with minimal parameters. The thinner and neater the work, the smaller the disk size should be.
Mini and micro grinders
By and large, a manual cutting machine has no right to be called a mini-grinder. So, to work with it, one strong man's hand is required in a full girth of the body. In some cases, you will need the help of a second hand. But the name stuck. For household needs, electric grid machines are used, and in some places also pneumatic machines. According to their functionality, they are divided into micro and mini grinders.
The micro angle grinder is held in the hand like a ballpoint pen. The cutting or grinding disc has a diameter of no more than five centimeters. These tools have found their use, for example, by dentists and jewelers. Read about the features of the grinding disc for wood here.
Mini grinders have received a wide range of applications due to their capabilities. Average power, convenient size of discs, adjustable handles allow them to be used when cutting sheet metal and rolled various shapes with a thickness of up to 8 mm, cut down trees or branches, process pressed wood or fibrous panels, clean cut corners. And this is far from the full range of capabilities of this practical tool. With certain skills, curly cutting and artistic surface treatment of metal or other material is possible.
Power angle grinder
This parameter sets the performance of the tool. At higher values, you will be able to work for a longer period with maximum tool loads. Therefore, the complexity of the planned construction manipulations must be taken into account.
You can find both low-power 600 W units and more efficient 2700 W units. In this case, the choice depends on the disk used in work.For ultra-small circles, it is advisable to take simpler units according to the "engine" - 600-1000 watts is enough.
1200-1500 W machines are more varied in options. This can be seen even in the photo of the angle grinder. For the operation of circles 180-230 mm, a 1500-2700 W tool is recommended.
For example, to work with thick concrete and bricks, you need to choose devices from 2 kW with a large disc, and for simple home repairs, you can limit yourself to a machine up to 1500 W with a disc up to 125 mm.
Metal cutting rules
If you have never used a grinder before (regardless of its size), then in order to avoid mistakes, it is better to try them on old parts. Please note that the effectiveness of using the cut-off wheel can only be achieved if radial forces are ensured. When processing materials in a plane that differs from the one that was initially determined, at the moment when the disc is already inside a metal workpiece, the risks of its breakage increase, as well as the fact that it will be unusable in the future.
When cutting metal, you get the best results by using the blade heel. This zone corresponds to the near-bottom part of the circle. The durability of the tool and disc can be ensured by arranging breaks every 5-7 minutes for 20-30 minutes. This must be remembered first of all by the fact that it uses a low-power device that can overheat.
Also, to extend the life of the blade, you can cool the metal by treating the cutting area with water.
Application conditions for processing different materials
When working with aluminum blanks, one should not forget that aluminum has a very viscous structure. If the workpieces are thick, it is recommended to lubricate the seams with kerosene. But during this procedure, do not forget about the observance of fire safety rules.
In the conditions of using a small tool for molding, curly carving or cutting sheet metal, it is necessary that it be completed with "stubs" - worn out discs. Therefore, the remnants of this material must be preserved. For accurate cutting of the corners, the procedure is performed in two stages, while both shelves are sawn separately.
When machining very long pipes, fittings or corners previously fixed to supports, it is recommended to cut the overhanging edge for the result to be effective. If the cutting line passes between the supports, there is a risk that the workpiece will bend under the pressure of its own weight, and this will jam the disc.
When working with thinner workpieces, remember to cut in an extremely straight line. When you need to cut out a shaped element, first you need to make a straight-line dimension, and then remove the unnecessary remaining fragments.
When you work with a grinder, do not put pressure on it. Otherwise, there are the following risks:
- the disc may jam;
- break down;
- the grinder can overheat.
When during operation you see that the metal is cutting very slowly, then this indicates that the disc probably needs to be replaced.
If, after making a cut, you decide to give it a neat look with the side of the disc, then don't do it. In this case, you must use a different type of disc.
Also, when using the tool, it must be borne in mind that if abrasives or molten metal particles get on plastic products, car windows or headlights, then it will be almost impossible to remove them from there. Therefore, even before starting work, all these items must be removed from the risk zone and protective measures must be taken in advance.
So, the features of the use of grinders, in particular, their mini-versions, were considered above. Their functional features practically do not differ from larger models, but they also have a number of advantages. In particular, they are more user-friendly.And if we consider that small models have a more affordable price, then this can be a decisive factor for the purchase of this tool for processing surfaces and materials for household needs.
