What The Angle Grinder Consists Of

Maintaining constant disc speed

What The Angle Grinder Consists Of

At the moment of contact between the working disk and the work surface, the tool rotation frequency may decrease, while the friction that occurs increases the load on the engine. The constant speed control system used is able to compensate for this resistance, ensuring a constant cutting speed. Professional models of grinders are equipped with such systems, which allows such a tool to be distinguished by its durability, and the angle grinder guarantees the quality of the work carried out.

Rotational speed

The most important parameter of the tool is the rotation speed of the jar, which depends directly on the diameter of the nozzles used. For domestic use, it is recommended to choose models of grinders in which the linear speed of rotation of the circle is 80 meters per second. At higher speed use ordinary household nozzles on an angle grinder is not possible, since the wheel will simply collapse due to the increased load. But at a lower rotational speed, rapid wear of the discs is noted, and it is often impossible to work with such a tool.

What you need to know about angle grinders?

recently, a new attachment for an angle grinder has appeared on sale.Dust protection means a special attachment in the form of a casing with a bell for connecting a construction vacuum cleaner.

Characteristics of the main models of grinders

The characteristics of the device determine its strength, functionality and reliability.

Cutting circle diameter

  • This is one of the most important criteria when choosing an angle grinder. This parameter affects how much material it is able to cut. The diameter of the nozzle varies from 115 to 230 mm.
  • Angle grinder with 115 mm disc is used for the simplest work. Mainly used for surface grinding. The power of the device for this nozzle should be from 0.6 to 1.0 kW.
  • The 125 mm wheel is used for both cutting and grinding in a domestic environment. For the application of this disc, the angle grinder can be operated with small dimensions and good performance at a power of 0.75 to 1.5 kW. This model is not suitable for thick parts.
  • Angle grinder with discs of 150 and 180 mm are used not only for work at home, but also at a professional level. These circles are capable of cutting pipes, slabs and other thick materials. The power of the device for such nozzles should be within 1.52.7 kW.
  • A circle with a diameter of 230 mm allows you to easily cut any thick building material such as stone, tiles, pipes, etc. It is undesirable to use such an attachment for grinding work, since an angle grinder for this disc has a lot of weight and power, which can be detrimental during grinding. Affect the result. Suitable for professional builders who are engaged in construction and renovation on an ongoing basis.

Engine type and power

Most of the grinders are equipped with universal collector motors, due to which the tool is relatively cheap.

As an alternative, there is a more modern version of an asynchronous electric motor with control electronics, among which, for example, a current frequency converter.

These motors are installed mainly on professional-grade equipment.

As for the engine power of the angle grinder, this parameter for most models is within 0.7 2.2 kW.

In general, the performance of the tool depends on the power, as well as the efficiency of work with various materials.

So, for example, for grinding metal and sawing concrete, 600 900 W are required, for more complex work 1 1.5 kW.

The more powerful the tool, the more stable it works under load.

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Dimensions and weight

The dimensions of the grinders are determined by the maximum diameters of the discs for which they are designed to work.

By size, grinders can be divided into several types:

  • Small with an average length of 270 mm and a height of 100 mm, for discs of 115 125 mm.
  • Medium 350 mm long and 120 130 mm high, for discs 150 180 mm.
  • Large, 400 mm long and over 140 mm high, for 210 230 mm discs.

As for the weight of the grinders, it ranges from 1.8 to 6-7 kg.

The standard bore diameter of the discs is 22.2 mm, their thickness is 0.8-2 mm, and the outer diameter is 100-230 mm.

What this tool can do

The classic angle grinder is a hand-held power tool with an abrasive wheel. The main purpose of the angle grinder is the processing of joints of flat metal surfaces. However, it can be used for other operations as well. The base circle is ideal for cutting sheet metal, trimming pipes and rebar. By simply replacing the working wheel with a disc with sandpaper, the sander turns into a polishing one. An angle grinder can be used as such when machining handrail pipes, flat or curved surfaces to a mirror finish. In addition to metal work, the angle grinder also cuts ceramic tiles. To do this, a concrete circle must be used as a working disk. The list of operations that can be done with an angle grinder is very wide.

Each type of material requires special discs for its processing:

  • Grinding disc for metal 5-6 mm thick;
  • Flap grinding disc;
  • Cutting wheel for metal 2 mm thick;
  • Cutting wheel for concrete and ceramics with a diamond edge;
  • Cut-off circle on wood;
  • Chain circle for wood.

Why an angle grinder and how it works

Today, almost every home craftsman has an angle grinder in everyday life. However, many do not know why it is called that, and what functions this tool can perform, in addition to conventional cutting. From this article you will find out the origin of the unusual name of the angle grinder, its structure, and what else it can be used for.

What is the correct name of an angle grinder

The familiar name of the angle grinder is so common that few people remember why it is called that. This tool is correctly called an angle grinder (angle grinder). Initially, it was intended for processing internal corners at the joints of two planes. The first copies of such machines arrived in the Soviet Union from then friendly Bulgaria, where they were produced. According to the habit of the people, they tried to shorten the long and uncomfortable name. As a result, the new word angle grinder has firmly entered into use. But the correct name of the angle grinder is indicated on the packaging.

Gradually, all power tools that looked like a prototype began to be called so. Although there is a difference between them. For example, an angle grinder is often called a cut-off machine.

The external similarity is undoubtedly present, but the cutting machine is equipped with a platform so that the cut is directed perpendicular to the surface to be processed, which makes it different from an angle grinder.

The device and principle of operation of an angle grinder

The device of an angle grinder is quite complicated. What an angle grinder consists of, you can understand by looking at the figure below.

The design of the machine can be conditionally divided into two parts:

  • Electric;
  • Mechanical.

A simplified electrical diagram of an angle grinder looks like this:

The heart of the angle grinder is an AC collector motor. The supply voltage through the stator winding by means of carbon brushes is supplied to the collector of the rotor (rotating part) of the electric motor. There are winding sections on the rotor, the terminals of which are located on the rotor armature plate.

On both sides of the rotor shaft, bearings are put on, fixed in the housing. This ensures stable direction of the shaft during operation. The rotation of the electric motor is transmitted to the gearbox, which changes the direction of rotation and transfers the torque to the cutting wheel.

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The reducer consists of two helical gears. The small one is put on the motor shaft, and the large one is on the gearbox axis. A working tool (circle) is attached to the outward part of the gearbox axis. Professional models are equipped with a release clutch, which stops the rotation of the working part of the tool if, for any reason, the wheel is jammed in the material being processed. Without such a clutch, the disc of the circle can break and fly in different directions in fragments. Part of the surface of the circle is covered with a protective cover that protects the face and hands from sawdust and dust flying from under the cutting edge.

The working wheel is attached to the spindle with a quick-clamping nut using a special wrench. The immobility of the spindle when tightening the nut is provided by a button on the side of the gear housing opposite to the circle. The plastic housing of the angle grinder has longitudinal slots. During operation, they cannot be closed, through them the electric motor is cooled.

Power

  • The power of the devices is in the range from 0.6 to 2.7 kW.
  • Low-power machines are of little use, they are not recommended for long-term operation.
  • For cutting stone, pipes and other thick and hard materials, the power of the angle grinder must be at least 2 kW. And for grinding or cutting thin material, 0.71.0 kW is enough.
  • The time resource of an angle grinder depends on the value of its power: the more it is, the longer you can work with it.

Angle grinder device and characteristics of its main models

The device of angle grinders for all its types is practically the same, they all have the same units and components. The main differences between the models are in the presence of additional components that perform different functions. For a complete understanding, consider the device of an angle grinder and its main characteristics in more detail.

Additional model functions

The number of additional devices affects the cost of the device.

List of common functions:

  • A device for smooth switching on of the grinder, which allows you to gradually pick up the speed of revolutions per minute. This function eliminates sudden jumps when turning on the angle grinder, which increases its service life.
  • Function of protection of the mechanism of the angle grinder from jamming of the disc, when it appears, the tool automatically turns off.
  • Adjustable handle position, which is great for left-handers.
  • Adjustment of the number of spindle revolutions. This function allows you to set a certain number of revolutions required for different types of work, while saving electricity and consumables.
  • Protection function of the angle grinder from being switched on again, which is necessary in the event of a temporary power outage when the device is forgotten to be pulled.
  • Constant speed support. This function is needed when carrying out long and laborious work.
  • Damping the vibration of the device during its operation. Makes the device work more comfortable.
  • Cutting wheel quick changer.

Characteristics of the main models of grinders

The characteristics of the device determine its strength, functionality and reliability.

Cutting circle diameter

  • This is one of the most important criteria when choosing an angle grinder. This parameter affects how much material it is able to cut. The diameter of the nozzle varies from 115 to 230 mm.
  • Angle grinder with 115 mm disc is used for the simplest work. Mainly used for surface grinding. The power of the device for this nozzle should be from 0.6 to 1.0 kW.
  • The 125 mm wheel is used for both cutting and grinding in a domestic environment. For the application of this disc, the angle grinder can be operated with small dimensions and good performance at a power of 0.75 to 1.5 kW. This model is not suitable for thick parts.
  • Angle grinder with discs of 150 and 180 mm are used not only for work at home, but also at a professional level. These circles are capable of cutting pipes, slabs and other thick materials. The power of the device for such nozzles should be within 1.52.7 kW.
  • A circle with a diameter of 230 mm allows you to easily cut any thick building material such as stone, tiles, pipes, etc. It is undesirable to use such an attachment for grinding work, since an angle grinder for this disc has a lot of weight and power, which can be detrimental during grinding. Affect the result. Suitable for professional builders who are engaged in construction and renovation on an ongoing basis.
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Disk rotation speed

  • This indicator indicates how many revolutions per minute the spindle is making. The value can be in the range from 2.8 to 11 thousand rpm. The smaller the disc, the more revolutions. For example, with a circle of 115 mm, you can work at a speed of 11 thousand rpm, and 180-230 mm at a speed of 6 thousand rpm.
  • Almost all models are equipped with a wheel speed control device, which is carried out using an installed regulator, which allows you to reduce or increase the number of revolutions per minute.

Components Angle Grinder

An angle grinder consists of the following components:

  • Impact resistant plastic housing. The structure consists of two elements connected by screws. There are holes in the area where the engine is located for its timely cooling.
  • Angle grinder electric motor, consisting of the following elements:
  1. Stator consists of two-pole coils with copper wire winding. Coils have a certain number of turns, according to the technical specifications of electrical engineering.
  2. Rotor located inside the stator and secured with a bearing connection. One bearing is located inside the gear housing, the second next to the manifold and is fixed directly in the plastic housing. A rotor is made of electrical iron with slots for the location of the winding wires. The number of slots and the pitch of the winding affect the speed of the revolutions produced.
  3. Electric brushes provide a supply of electricity from the cable to the collector. Under normal operating conditions, they have a steady glow, which is visible through the ventilation hole. If you notice interruptions in the glow or its absence, this is the first sign of their breakdown.
  • The gearbox housing is made of a durable aluminum alloy that conducts heat well. It serves for fastening the gearbox elements. It has holes for installing an additional handle, which creates convenience during work.
  • The reducer is designed to supply energy to the trimming disc from a rotating armature, thereby ensuring its rotation. It is the gearbox that is responsible for the number of revolutions of the grinding wheel.

The mechanism of the gearbox itself:

  1. There are two bearings on the axle on which the driven planetary gear rotates.
  2. One end of the shaft contains a nut thread that grips the trimming disc.
  3. A sun gear is pressed onto the axis of the armature of the electric motor, which is leading in relation to the bevel gear.
  • The release clutch is a device designed to prevent kickback in the event of a grinding disc jamming during operation. It consists of two disks tightly pressed against each other, preventing an abrupt stop of the rotating rotor shaft and the loads arising from.
  • Spindle speed control device. But not all models of angle grinder have such a device.
  • Buttons for starting the engine and smooth starting the device into operation. This button allows you to gain spindle speed gradually, which relieves the load on the electric motor and prevents possible injury.
  • The SJS system is designed to protect the electric motor from overloads that occur if the wheel gets stuck in a building material. Not all models are equipped with this system.
  • Button for easy removal and replacement of the disc, locking the planetary gear in the gearbox while unscrewing the nut in the disc holder.
  • Cylindrical nut for attaching the grinding wheel. Clamping is done with a special key.