Why an angle grinder, and how it works
Today almost every home handyman has an angle grinder. However, many people don’t know why it’s called that, and what functions this tool can perform besides conventional cutting. From this article you will learn the origin of the unusual name of the angle grinder, its device, and for what else it can be used.
Everyone familiar name. angle grinder. so common that few people remember why it is so called. This tool is properly called an angle grinder (angle grinder). It was originally designed for working inner corners at the joints of two planes. The first examples of such machines came to the Soviet Union from the then friendly Bulgaria, where they were manufactured. In accordance with the habit of the people of a long and uncomfortable name tried to cut. As a result, a new word has firmly fallen into use. angle grinder. And here on the packaging indicates the correct name. angle grinder.
Sometimes manufacturers use a variant of SHMU (angle grinder) or MSHU.
Gradually all power tools that look like the prototype began to be called so. Although there is a difference between the two. For example, an angle grinder is often called a cut-off machine.
The external resemblance is undoubtedly present, but the cutting machine is equipped with a pad so that the cut is directed perpendicular to the processed surface, which distinguishes it from the angle grinder.
Angle grinder. what is it, application, choice, safety precautions
An angle grinder, or angle grinder, or angle grinder is a hand-held power tool for cutting, grinding and other procedures for processing metal, stone and plastic. The device has a small cylindrical body, on one side of which is a device for installing accessories on the spindle, on the other side. a handle for holding the device during work. Inside there is an electric actuator powered from 220 V domestic mains.
Angle grinder differ in size, power and the corresponding scope of application into 3 main types:
- Large. Dimensions 500 x 150 mm, power up to 3000 watts. Can be used for production. Capable of working continuously for a long time. Have a long service life.
- Medium. Dimensions of the body are 350×130 mm, power up to 1.5k. W. Used in professional work. Can be used for several hours a day.
- Small. Dimensions do not exceed 270 x 110 mm and the power is 1.2 kW. Designed for household purposes. Allowed to work for a limited period with pauses.
Most often, small models of angle grinder power up to 1.2 kW are used for domestic purposes Source expertnov.ru
Sometimes those who are just beginning to use the angle grinder, reduce the basic rule of operation to the decision of which way to unscrew the nut to change the nozzle. In reality, this is just the technical side of maintaining the device. in order to use it successfully, you must first of all choose the right model for its purpose, convenience and power.
For example, the most comfortable operation will contribute to the correct selection of the device on such a number of parameters as:
- The number of handles, their location, the presence of anti-vibration pads.
- Motor power. The characteristic must match the work as well as the types of tools used. Thus, the smaller the disk, the higher its rotation speed. However, the use of a wheel that does not comply with the manufacturer’s recommendations, can lead to a breakdown of the equipment and violations of safety rules.
- High quality. Both the device itself and replacement nozzles must be of proper quality. Because the work involves rotating mechanical parts, the destruction of which can have catastrophic consequences.
Only high quality angle grinder and tooling allows you to quickly and safely cut workpieces Source 1metallocherepica.ru
One of the main conditions for effective work with the angle grinder is the observance of safety requirements. First of all, these include:
Before you start working with the angle grinder you must prepare the area according to the following requirements:
- Select an even and sufficiently large free area.
- For maximum reliability and safety of application of the angle grinder processed workpieces are fixed to the bolt connection with the right side, and if necessary, unscrew and reinstall in accordance with the work plan.
- If necessary, remove nearby objects that could be damaged by sparks, smoke and other factors in the operation of the device.
- Remove all flammable elements. solvents, fuel, rags, etc from the work area.
- When working at the construction site with construction material, prepare primary fire extinguishing equipment. sand, fire extinguisher, water supply.
The angle grinder must be operated in dry weather outdoors and indoors with normal humidity.
There is risk of injury if you use an angle grinder in the home. Therefore, to be on the safe side, the user must wear the following protective equipment while working:
- Wear goggles or a face mask to prevent sparks or splinters of material and disc.
- Use earplugs or building earphones to muffle sound.
- Protect your hands with gloves or mittens made of thick fabric. The material must not be old, worn, with loose threads, and the workmanship must be accurate.
- Use a respirator to prevent dust from entering the respiratory system.
- Wear thick leather boots with metal inserts on the socks to protect feet from sparks and falling objects.
In addition, the entire body must be securely covered with thick cloth overalls. In this case, the form should not have loose parts that can get caught up in the rotating elements of the device.
To successfully operate an angle grinder, each user must have an idea of which way to unscrew the disc and how to change it at all. However, in addition to this basic requirement, the instrument should be checked for proper operation on the following points before starting work:
- The power cord and the plug must have an intact sheath, be free of kinks and other defects.
- The blade guard is fastened firmly and facing in such a way that no sparks can reach your clothing or face.
- Gear knob must be solid, without cracks and firmly screwed in.
- The blade should be straight and without the slightest twist.
In addition, any user must know how to properly use the angle grinder, which direction of disc rotation in relation to the material to be processed.
The machine’s construction
the angle grinder consists of several parts, the coordinated work of which leads to excellent performance of the tool.
- The driving element of the angle grinder is the electric motor. It is inside a cylindrical body.
- The motor shaft is connected to the rotating mechanism. It is an axle, one end of which protrudes from the body.
- This part accommodates nozzles in the form of discs of various diameters and coatings.
- The discs are attached to the gearbox with a special nut. Some models also have a hole around the instrument’s perimeter. They are used to fasten the tool bits with a tightening wrench.
- In addition, some models (mostly low power) are equipped with a battery, which is charged using a special base. It comes with the tool. In other models, where there is no battery, the power is supplied through a cord connected to the mains using a standard socket.
The body of the angle grinder is made of very durable plastic, and the gearbox. of magnesium alloy. This guarantees the strength and durability of the tool. There are also rubber pads on the body. They are designed so that the tool does not slip in the hands during work.
Existing classes of angle grinder
Like any other tool, angle grinders are divided into classes: household, professional and industrial (the tool of the last class is not considered here).
For a domestic tool, the character of a small power and minimal functionality. Gearboxes of such angle grinders are made of dural, and therefore are less resistant to wear than expensive steel ones. The motor windings of cheap tools are usually covered with a thin layer of low-quality varnish. If the permitted temperature threshold is exceeded, the lacquer melts and causes a short circuit and irreparable damage to the motor. Designed household angle grinder for occasional work.
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Professional tools have more power and endurance, often have useful features missing in household angle grinder. Such a tool costs more than a household tool, but there is a price to pay. Professional angle grinders usually include better parts and an improved cooling system, which allows you to work longer without interruption. Useful attachments, such as an anti-vibration handle or a quick-clamping flange, may be included.
Still, the final choice in favor of this or that class master makes on the basis of actual needs. If you need a tool occasionally and for minor work, a household appliance is quite enough. But if you plan to work in earnest, it is better to overpay for a solid piece. In general, it is better not to save on the quality of a tool.
If the budget is very limited, and buying a cheap angle grinder is the only viable option, you should strictly follow the mode of operation specified in the documentation: 5 minutes work. 15 minutes rest.
How not to work with an angle grinder
Safety precautions when using an angle grinder should be in the first place. According to it, it is forbidden:
- perform work manipulations without using PPE;
- Wear light clothing that does not completely cover the body (arms, legs);
- use a machine that is not equipped with a spark guard;
- without checking the performance of the tool at idle speed to start using it;
- work with a disc that is defective or unsuitable for the material;
- to be positioned in the plane of the cut;
- apply excessive pressure to the tool;
- work in such a way that the direction of rotation of the wheel was in the direction of the operator;
- perform the work without taking breaks, because your hands get tired, and it is difficult to hold the angle grinder firmly;
- that the workpiece to be machined is not secured (e.g., in a vise or with clamps);
- grind metal parts with the side of the disc;
- Perform cutting of workpieces, the thickness of which exceeds half the value of the radius of the circle used;
- presence of unauthorized persons in the work area;
- touching nozzles until they cool down because they get very hot when cutting and grinding from friction;
- turn the tool on when deepening the wheel into the workpiece;
- grinding with thin discs;
- use nozzles with a larger diameter than the angle grinder is designed for;
- place the workpiece so that when you cut, there is a clamping of the wheel (the cut must be for breaking, not for squeezing).
Safe use of the saw in the angle grinder ensured by the fact that its replacement is carried out only when the device is unplugged.
how much is the cost of the angle grinder?
At the same time on the market are available and very cheap models, characterized by minimal functionality. For example, the model DEFORT DAG-500-B is available in online stores at a price of 700 p. If you decide to choose such an angle grinder, you should know that this machine will give you the opportunity to grind and no more.
Be that as it may, if you’re worried about the question “What angle grinder to choose?”Give preference to well-known brands. their products, even in the lower price range, are always up to the mark.
Angle grinder selection parameters
Before you buy an angle grinder, it is recommended to get acquainted with the main parameters of this tool. This will help you choose a device with optimal technical characteristics that are suitable for the type of work that you are going to perform with the angle grinder.
It is not difficult to guess that the more power a motor is capable of delivering, the harder the tool will work, and the harder and thicker the materials it will be able to cut.
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Increasing the power of the machine inevitably leads to an increase in its weight.
Industry produces angle grinder with a capacity in the range from 0.5 kW to 2.7 kW. For home use and cutting non-thick materials, a tool with a capacity of up to 1.2 kW will be sufficient. Accordingly, to cut strong and thick materials will require that the angle grinder has a power of over 1.2 kW.
Working disk size
The diameter of the cutting disc mounted on the angle grinder depends on the depth to which it can plunge into the workpiece. The thicker the workpiece, the larger the disc diameter is needed.
Manufacturers produce angle grinders of different sizes and different power, and these parameters determine the maximum disc size that can be installed on the spindle of the machine. 5 standard sizes of discs and attachments are available for the angle grinder.
- 115 mm. This mini disc is ideal for cutting plastic, slate, thin-walled metal pipes, thin sheet metal. You can also use the 115 mm disc for grinding and other small jobs.
- 125 mm. Disks of such diameter and, accordingly, the angle grinder, designed for them, are the most common for home works. Therefore, the largest range of 125 mm diameter wheels for these devices is available for sale. Suitable for cutting tiles, pipes, stone, slate, metal rods, and for polishing and cleaning various surfaces.
- 150 mm. Mainly used for cutting concrete, steel and stone. Not suitable for grinding small parts.
- 180 mm. Often used in construction work to cut stone and concrete, ceramic tiles, thick metal pipes, rebar, and bricks. Not suitable for grinding, as the weight of the machine is too heavy for this application.
- 230 mm. Used for rough building work, for cutting heavy materials: concrete, brick, artificial or natural stone. Also suitable for cutting thick metal pipes, channels and boards of any diameter with 230 mm discs.
If the machine manual specifies the maximum permissible disk size, you can use smaller-diameter disks on this device as well. For example, if the maximum tooling size for a particular machine model is 180 mm, you can put tools from 115 mm to 180 mm on it.
The speed of the disc fitted to the angle grinder is directly related to its diameter. The larger the diameter, the lower the rotational speed required.
The speed at which the disc of the angle grinder rotates can range from 2800 to 11000 rpm:
- for small disc diameters (115 or 125 mm), the maximum speed allowed is 10000-11000 rpm;
- for discs of size 150-180 mm is already limited speed. not more than 8500 rpm;
- the rotation speed is limited to 6650 rpm for the larger 230 mm discs.
All speed limits are not random. Studies by specialists have shown that the speed of the disc edge (linear) should not be higher than 80 m/s. Otherwise, there is a high probability of disc failure, which could lead to injury to the user by its fragments. So be serious about how many revolutions you set on the grinder for a particular tool.
angle grinders are available with one or two handles. The datasheet usually indicates that the tool has either a short or long handle. Small angle grinders designed for 115-125 mm discs usually have one detachable handle. You have to grasp the handle with one hand and the body of the machine with the other hand when you are working. The photo below shows an angle grinder with one handle.
If the tool has a long handle, you’ll see an ergonomic holder on the back of the tool that is comfortable for your hand. In addition, there is a start button at this point. The following photo shows an angle grinder with a long handle, that is, with two holders.
Therefore, it would be better if machines with discs larger than 125 mm had an additional rear handle.
It is also important to have mounting points for the auxiliary handle, as shown in the following photo (the numbers from 1 to 3 indicate the mounting points of the holder).
Variable handle allows the tool to be used in different positions, depending on the work site.
It is also advantageous if the back handle can be pivoted around its axis.
angle grinders of the “pro” class are often equipped with anti-vibration handles. Its use greatly reduces hand fatigue during long-term work. In addition, the reduction of vibration prevents occupational diseases associated with it.
Power type of tool
According to the type of power supply angle grinders are differentiated into mains and cordless. Electric-powered machines are most common among owners of angle grinders. they have a good power, high rpm and can work for a long time.
Characteristics of angle grinders
When choosing a power tool, you need to pay attention to such characteristics as tool diameter, power, speed range, and the ability to adjust them.
Speed of rotation
The most important parameter of the tool is the rotational speed of the tool, which depends directly on the diameter of the bits used. For domestic use, it is recommended to choose the models of grinders, which have a linear speed of rotation of the wheel is 80 meters per second. At higher speeds, the use of ordinary household attachments on the angle grinder is not possible, because the circle will simply collapse due to the increased load. At lower rotational speeds, on the other hand, discs wear out quickly, and it is often impossible to work with such tools.
On sale you can find angle grinders, the power of which ranges from 650-2700 watts. Power ratings will depend not only on the purpose of a particular tool, but also on the diameter of the discs used. For example, models that are designed for larger-diameter discs, have a powerful drive that develops 2 thousand. W or more. Such equipment belongs to the category of professional appliances, is equipped with reliable powerful drives and has a corresponding cost.
But domestic models grinding machines, the disk diameter which is usually 125-150 millimeters, have a capacity of at least 750 watts. For domestic purposes, we can recommend choosing such angle grinders with power 750-1500 W, and keep in mind that the bigger the wheel and disk you plan to use to work, the higher power should be such a tool.
Diameter of the tooling
Before you buy, you also need to determine the diameter of the tooling that will be used with the angle grinder you have selected. This diameter indicates the maximum size of the wheel for use with a particular angle grinder model.
In the event that you choose such a tool exclusively for work with lumber, then a tooling diameter of 125 or 150 millimeters will be sufficient. But if you plan to use an angle grinder to cut curbstones and other materials that have a great depth, then you should choose such a tool, which has a maximum tooling diameter of 200 millimeters or more. It should be noted that models with tooling diameter of more than 200 millimeters are referred to professional tools and have the corresponding cost.
If you need to pick up such a tool for domestic use, then you should decide on the mode of operation, as well as the work for which you purchase the angle grinder. Domestic models of grinders are characterized by simple design, power at the level of 1000-1500 watts and size of tooling, which usually does not exceed 150-175 millimeters. Based on these two characteristics and should choose angle grinders for home.
Professional models of lathes have a tooling size of 200 millimeters or more, their power indicators exceed 2 thousand. W. The tool is equipped with protection against dust, vibration, and is able to operate in the most rigorous regime. Such equipment is durable, but it has a high cost, which is explained by the complexity of design and the use of high-tech stuffing.
The following safety precautions should be followed when working with the tool:
- Do not use accessories that do not match the size of the angle grinder and have any damage.
- Be sure to use gloves and safety glasses for the eyes.
- When working with a specific material, use only tooling that is specialized for it.
- Place the power cord in such a way that it will not be damaged.
- Make sure that there are no people in the plane of the disc rotation.
Violation of simple safety rules can lead to various injuries, and in some cases even to death as a result of damage of vital organs by fragments of the blade.
To determine the choice of angle grinder, you need to know for what specific purposes you need the tool and with what frequency it will be used.
Given the average needs of home masters and the work they perform, you can advise a network machine from a well-known manufacturer with a circle diameter of 125 mm. As a rule, such tools are suitable for most jobs. It is not expensive, and offers from different manufacturers are plentiful.