How to remove the guard from an angle grinder

How to remove the disk from the angle grinder without a key

Working with any mechanisms, you should always expect abnormal situations, which can not always be solved in accordance with the manufacturer’s recommendations. Angle grinder is no exception. You could encounter excessive clamping of the cutting disc at work. This problem is especially common with large, powerful models, over 2 kW. What to do if the disc on the angle grinder jammed or the nut does not unscrew? Let’s deal with this question further on.

When rotating at idle speed, it is difficult to encounter such a problem. Especially when working with light discs and soft-start tools. However, after increasing the RPM and making contact with the surface to be cut, the following happens:

  • When material resistance occurs, the wheel’s angular velocity of rotation is sharply reduced, it brakes.
  • The motor continues to run for a few moments at the same speed due to inertia, dragging the gearbox and spindle along with it.
  • The retaining nut is tightened more by inertia on the threads of the spindle head, thereby pressing the cutting disc in.

The tightening process of the locking flange is now complete. an abnormal situation is evident. The following factors influence its occurrence:

  • Large wheel size.
  • High tool power.
  • Massiveness of the rotor.
  • Rapid increase in cutting depth, t.е. increased resistance.

In this case it can be very difficult to remove the disc from the angle grinder. Extra measures have to be taken.

Why are the sparks flying?

Metal angle grinder discs rotate at unbelievably high speed and during rotation, the cutting material begins to heat up.

The smallest metal or stone particles begin to heat up and form sparks as they rub against each other. A stream of sparks can be very dangerous for the operator, as well as for people and objects standing nearby. Sparks can burn, causing textiles or dry grass to catch fire.

The tool you need for repair

To repair a Bosch angle grinder, you can not do without tools. Let’s specify right away, if you have an electric screwdriver, it will greatly speed up the process of disassembly and assembly of the tool.

But you can do without tools and a set of screwdrivers, preferably with ratchet mechanism. Do not do without the open-end wrench, which will be used to unscrew the nut fixing the helical drive pinion.

It is better to have a special puller for bearing disassembling.

Diagnosis of the electrical part can be made with a tester or a device for determining the short circuit of turns.

especially useful to determine if there is a rotor or stator malfunction without removing the assembly.

Bosch angle grinder diagram will help to perform repairs on your own, and this manual will help to cope with any problem with dignity.

How to unscrew and properly place the disk on the angle grinder

This simple operation sometimes baffles even experienced locksmiths or users of angle grinder. The reason is that the disk is fixed by a special nut. The nut has 2 or 4 holes into which a special wrench is inserted. This wrench is always included with the purchase of the angle grinder. It may still be included in the kits.

According to the instructions to the angle grinder, you need to press the lock pin which is located on the back side of the gearbox. When the shaft is fixed, a special wrench must be used to unscrew the nut and change the disk. But it is difficult to unscrew the nut if it is not jammed. And clamps it with such a nut almost always. Attempting to unscrew the disk leads to breakage of the retainer behind the gearbox.

What solution to the problem is suggested by specialists and amateurs

  • Install a gasket from newspaper under the nut;
  • Install a gasket made of a plastic bottle under the nut;
  • Replace the nut with a nut of a different design.

What is a gasket made of newspaper.

remove, guard, angle, grinder

This is a paper washer according to the size of the nut. It is put on the mounted disc and a nut is screwed on top. This paper was the stumbling block because the Safety Inspectorate always said that this solution was harmful.

The representatives of the safety authorities have the same attitude towards the installation of shims of any other material:

But there is a solution, which does not contradict the safety requirements and allows for normal installation and removal of the disk. This is a special nut that consists of two elements, a nut and a pressure washer. Using such a nut does not require any pads, because with it the disk does not jam.

If there is no special wrench on hand, the craftsmen suggest to do without a wrench. This does not mean that you can do without a wrench at all, but use a “gas wrench” or other device. To do this, you need to clamp the retainer, clamp the nut with a gas wrench and unscrew it. It is possible to replace a jammed disc this way, but it is a very inconvenient operation for one person.

There are also suggestions to clamp the disk by hand and unscrew it this way. Maybe, but it is unlikely that you can change a broken disc this way. It is better to use wrenches that are designed for removing and installing discs.

Some foreign power tool manufacturers, such as Bosh, produce angle grinders with easily removable nuts. They secure the disk on the tool shaft and are quickly and easily removed for disk replacement.

How to remove a bogged disc with an angle grinder

Use of new nuts solves the problems of removing the disk, but what to do with an already jammed disk? Even when a disk is installed correctly, it is not always possible to remove it. Practice suggests different ways to solve the problem.

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You can clamp the locking device and strike the nut holes in the direction of unscrewing through the superstructure. This is only possible if the retainer is in good condition. But the ratchet can not withstand this way of solving the problem and break.

The second method is more logical. Under the clamping nut and bottom support washer there is a gearbox shaft with chamfered faces. On these chamfers the bottom support washer is put on. A standard wrench cannot be mounted there. it’s very narrow. But it is possible to take an ordinary open-ended wrench size “17” and turn it on both sides.

A sharpened wrench will fit in the gap, fit over the chamfers of the shaft, and lock it in place. Now any wrench will unscrew any nut, and the disk or its remains will be removed from the angle grinder.

How to put the right disc on an angle grinder

Grinding disks have different diameters, thicknesses and applications. Some are made to work on metal, others work on ceramics, and others work on wood.

On an angle grinder, you must install a disc of such size that it will not exceed the size of the protective cover. The size of the disc to be mounted is indicated in the manual and on the marking table of the angle grinder.

Disc thickness is selected according to the technological parameters of the processed material. All discs (grinding discs) have their own classification. The disc shape, abrasiveness, grit size, hardness, accuracy grade and unbalance grade are classified. It is the latter that is responsible for the fact that some discs start to batter during operation.

The grinding wheel has a front and a back side. The front side is that on which the manufacturer’s marking and branding are affixed. When installed on an angle grinder, the front side must be at the top.

Install the disc as follows. So that the work sparks with particles of machined material fly towards the operator. This is a safety issue. If the angle grinder breaks free, it will not fly toward the worker.

Therefore, to work with the angle grinder, you must always wear protective clothing or a thick apron. Eyes and exposed parts of the face must be protected with a mask or at least safety glasses.

The main faults of the angle grinder and their causes

According to statistics, the majority of cases of failure of the angle grinder are related to the electrical part of the machine. Some failures may be minor, which allows you to repair the angle grinder with your own hands. But, for example, if the burnout of the motor windings repair angle grinder can make only a specialist.

The angle grinder does not turn on

The reasons why the angle grinder does not turn on may be the following:

  • the electrical plug is faulty;
  • The electrical cable is defective;
  • the start button is broken;
  • the contact between the power cable and the button is broken
  • breakage of the contact wire of the electric brush;
  • Severe wear of the electric brushes;
  • Rotor or stator winding failure.

The angle grinder does not revolve

There are various reasons why an angle grinder does not pick up speed.

  • Breakdown of the speed control unit. To check this version, you need to connect the motor of the machine directly, bypassing the regulator, and check the operation of the device.
  • Malfunction of the electric cable due to permanent kinks or mechanical damage. A damaged wire starts to heat up under load and the engine speed starts to drop because of this.
  • Dust on the manifold. Contamination must be removed with alcohol.
  • Brush problems. They may be worn out or have a short contact wire as shown in the following photo.

Although the brush is half worn out, but is quite serviceable. Short contact wire does not allow the spring to press the electrode against the collector. This situation can also be the reason why the angle grinder stopped working normally.

Electric motor is heating up

Causes of the angle grinder being warm could be as follows.

  • Improper operation of the machine. Overloading can overheat the motor and often causes the windings to burn out.
  • Destruction of the bearings located on the armature. As a result, the rotor is caught in the stator, making it difficult to run the motor and the windings overheat. The problem can be solved by replacing the bearings.
  • Clogging of ventilation ducts, through which air flows to cool the motor. Vents must be cleaned of dust.
  • Breakage of the impeller that cools the motor. It is installed on the rotor, on the opposite side in relation to the manifold. If the impeller is broken, it must be replaced with a new one.
  • Inter-turn short circuits in stator and rotor windings. Rewinding of the coils or replacement of these parts with new ones is required.

The angle grinder sparks

If you notice a lot of sparking when you turn on the angle grinder in the place where the collector is, then the reasons for this trouble may be.

  • Armature winding damage: breakage of one or more winding sections, inter-twist connections. There is an increased noise, decreased engine speed and burned brushes.
  • The contact between the collector plates and the winding is broken.
  • Poor brush pressure. The springs overheat and can “anneal” and lose their elasticity with prolonged use of the angle grinder.
  • Unbalanced motor rotor.
  • Disturbance of the cylindrical surface of the collector. This sometimes occurs after a rewind if the armature is not turned on the lathe but mounted straight away on the machine. Brushes can also be observed to spark excessively in such a case.
  • Insulation between the lamellae of the collector is faulty. There may also be a blockage of the track slot by graphite or a breakdown between the lamellas.
  • Worn bearings that cause the rotor to run out also cause the brushes to spark strongly.
  • Poor armature shaft geometry. This usually happens when the motor is not carefully disassembled and the shaft is bent.
  • The wrong brand of graphite brushes are installed. Brushes are matched to the expected speed and voltage.
  • Lifting one or more blades causes the brushes to burn out quickly. This can be caused by overheating of the motor. As a result, the glass mass that forms the base of the collector softens and the blades begin to rise. Because the blades are raised, the brushes wear out very quickly.
remove, guard, angle, grinder

Why does the disc on the angle grinder jam??

disc jamming is caused by deviations in the operating modes of the angle grinder. If, for example, you suddenly increase the pressure on the angle grinder during operation, the working tool will show increased torque.

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To cope with connections that are badly rusted, put the part in a container, pour some vinegar in it and let it soak. Then clamp the part in a vice and unscrew the coupling with a gas wrench. If this method does not help, you should heat the connection with a blowtorch, gas torch or autogenom.

How to grind and cut with an angle grinder: recommendations

Grind with the edge of the wheel at an angle of 20 to 40 degrees to the surface.

Grinding is performed as follows:

EASY, FAST, SIMPLE Replace a Cutting Wheel on Angle Grinder With NO TOOL

  • Finer grinding wheels are not permitted.
  • Do not grind with the side of a wheel that was not designed for the job. Wheels are not designed for high lateral forces, so they can easily break.
  • Grinding should be performed with the edge of the wheel, which is inclined at an angle of 20-40 ° to the grinding surface. The angle grinder must move forward and backward with pressure.

Cutting of concrete, stone and tile must be performed by special wheels, which are designed to work with these materials. In the process of cutting will generate a lot of dust. The angle grinder has a socket for connecting a vacuum cleaner, which is designed to remove dust.

Using an angle grinder is not that difficult, you only need to follow simple rules.

How to remove a jammed disc from an angle grinder

This simple operation sometimes baffles even experienced locksmiths or users of angle grinder. The reason is that the disc is fixed with a special nut. The nut has 2 or 4 holes into which a special wrench is inserted. This wrench has always been supplied with the purchase of the angle grinder. It may still be included in the kits.

According to the instructions to the angle grinder must press the lock, which is located on the back side of the gearbox. When the shaft is locked in place, use a special wrench to unscrew the nut and change the disk. But it is difficult to unscrew the nut if it is not jammed. And clamping it with such a nut almost always.

Attempting to unscrew the disk causes breakage of the retainer behind the gearbox.

What is the cause of the malfunction?

Before you wonder how to remove the disk from the angle grinder, experts recommend to understand why the angle grinder bites the nut. It has been observed that this problem occurs predominantly in angle grinders that have a significant disc size. A disk over 18 cm is considered large. A torque is produced during operation.

remove, guard, angle, grinder

Next, when the master starts cutting, there is a small bump. In other words, the disc is being subjected to force. If the size of the nozzle is less than 12 cm, this impact will be negligible. If the disk is large, the nut is tightened more by inertia. As a result, it cannot be removed in the usual way.

information on how to remove the disc from the angle grinder is provided below.

What causes the problem?

It is difficult to encounter this problem when rotating at idle speed. Especially when working with light discs and soft-start tools. However, after increasing the RPM and coming into contact with the surface to be cut, the following happens:

  • If the material is resisted, the grinding wheel’s rotational angular velocity is severely reduced and the wheel brakes.
  • The motor continues to run at the same speed for a few moments due to inertia, dragging the gearbox and spindle along with it.
  • The clamping nut is tightened more by the inertia on the thread of the spindle head and thus the cutting disc is pressed in.

That’s it, the process of tightening the fixing flange is complete. the abnormal situation is in your face. The following factors influence its occurrence:

  • Big wheel size.
  • high power of the tool.
  • Massive rotor.
  • sharp increase in cutting depth, t.е. increasing resistance.

In this case, it can be very difficult to remove the disc from the angle grinder. Additional measures have to be taken.

First way

How to remove the disc from the angle grinder if it is broken and jammed by the compression nut? Of course, you can try to use a special wrench for angle grinder or gas. However, judging by the reviews, after making enormous efforts and spending time, the master may not get the expected result. Dismantling can be easier and faster. To do this, use pliers to completely break the disk. Due to the fact that during the work will fly small splinters, the master will need protective goggles (mask) and gloves.

Then you need to take a metal plate, the thickness of which is less than the disc. This plate will be used to grind away the remnants of the disk. To do this, you need to turn on the angle grinder, and the metal piece firmly clamped by the pliers. After performing these steps, the nut can be unscrewed even by hand.

Measures to avoid jamming

By taking care of safe operation of the angle grinder in advance, you save yourself the need to take measures to eliminate abnormal situations. Such measures include:

  • Place cardboard or plastic washers between disc, flange and spindle head. They do not allow the tool to jam, but even if darned, they can be removed/melted down and the element can be unscrewed with ease.
  • It is necessary to properly install the abrasive disc. To do this, the front side of the disk put on the supporting flange (the picture to the gearbox). It must not come into contact with the clamping nut. In this case, the role of a washer, which protects from jamming, will be the regular metal ring in the center.
  • On a clamping flange to weld an ordinary nut, which allows you to clamp the installed disc with the usual wrench.
  • Control the tightening torque. It is not necessary to apply excessive force to install the cutting element. Otherwise it will jam under heavy loads.

How to remove the disk from the angle grinder with a wrench?

If the special key that came with the angle grinder is not lost, then cope with the task will be easier. Those who are interested in how to remove the disk from the angle grinder, experts advise to first fix the spindle. It is on it that the disk is located and is pressed with a flange. It is disassembled with a wrench. To make this technically possible, the flanges are equipped with special holes into which the pins of the wrench are inserted.

To lock the spindle, press the button on the housing on the opposite side of the disk. Do not loosen the safety catch with the open-ended wrench, as otherwise the spindle will continue to turn. If the angle grinder‘s wheel is turning clockwise, turn the open-jaw wrench counterclockwise and vice versa. It is important that the flange gives way and moves out of the way. It can now be fully unscrewed and set aside. Then the old disc is removed and replaced with a new one.

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Tips

If you had to use a gas wrench, you must remember about the very powerful shoulder of such a wrench and the force applied to the parts of the “angle grinder”. If you are not careful, you could break the spindle lock or damage the gearbox.

All manipulations with the disc of an angle grinder must be performed with the power supply completely disconnected (the plug must be taken out of the socket). Any unintentional activation of the start button will cause the electric motor to start and the plunger rotation speed is very high. Injuries in this case can not be avoided.

Electrical malfunctions of angle grinders

The electrical circuitry of the main part of angle grinders is almost identical. The rotor transmits the torque to the power tool via a gearbox. The rotor is rotating in the stator’s field. The control circuits consist of a push button that regulates the speed and provides a soft start for the tool, carbon brushes that provide alternating voltage to the collector lamellae. Power to the tool is supplied through a connecting cable.

The main electrical faults of the angle grinder include:

  • breakage of the power cable at the inlet to the tool;
  • The carbon brushes are broken or worn out;
  • failure of the power button;
  • Breakage or short-circuiting of the stator;
  • Breakage or short circuit of the rotor;
  • Peeling or worn out manifold lamellas.

Troubleshooting angle grinder on the electrical part is best determined by a tester or other device. Suitable for these purposes and self-made device, popularly referred to as “arcashka.

Scheme of the angle grinder simple enough and does not require any special knowledge. It is only necessary to observe caution and safety when carrying out repairs and have the electrical engineering skills of a high school student.

Finding a broken power cord

One of the most common causes of damage is that the angle grinder does not start or stops while working. The cause of malfunctions of this kind is the breakage of the power cable.27 at the entry point. The fault can be eliminated by replacing the cable or by throwing out the damaged part. The problem can easily be found with a tester.

If there is no tester at hand, but there is a screwdriver with a neon indicator light, then the fault can be found by connecting the power wires to the phase in turn.

Problems with carbon brushes

The reliable operation of any power tool depends largely on the integrity and proper functioning of the carbon brushes. The quality of the carbon brushes and their correct alignment to the collector flats influence the performance of the rotor head.

Grinder Safety.- and lies you are told to scare you.

Remember! Carbon brush length must not be less than 8 mm.

Timely replacement of the carbon brushes avoids the majority of problems.

The carbon brushes are subject to wear, as indicated by the type of sparking on the collector area. Sparking must be uniform throughout the contact patch between the carbon brush and the lamellae and must not exceed a length of 8 mm or more. Circular sparking indicates a fault in the rotor circuits.

Use of carbon brushes on angle grinders is recommended, but only by the tool manufacturer. Homemade carbon brushes can be installed, but only for a short period of time and immediately replaced at the first opportunity.

Repair of the power button and the speed regulator

Button failures most often show up in difficult and unreliable tool activation at start up. The fault appears and disappears by itself.

It is unacceptable to work with an angle grinder with a faulty trigger. This malfunction leads to jamming of cutting discs during operation and their destruction with unpredictable consequences.

The defect is eliminated by complete replacement of the button for a new one.

Soft starter with speed regulator integrated into modern brands of angle grinders. It cannot be repaired, but must be completely replaced. No, advanced left-handed craftsmen, of course, will be able to repair such a unit as well.

Stator repair

Failure of the stator is indicated by spontaneous rotation of the machine shaft, the angle grinder begins to gain maximum speed. Such a malfunction indicates the emergence of an inter-turn short circuit in the stator winding.

Some faults can only be eliminated by specialists. To prolong the smooth operation of the stator can only be timely cleaning, lubrication and replacement of carbon brushes and bearings.

It is usually rare for the stator to fail. This is often caused by overheating of the tool during operation. The defect is manifested by strong heating of the angle grinder housing and the smell of burning insulation.

There may be a breakage or a short circuit in the stator. Without disassembling the stator, these faults can be easily found with the help of a device IR-32.

Faults can be eliminated by exchanging the stator. For DIY enthusiasts we can recommend rewinding the defective stator with your own hands. There is nothing complicated about it.

Remove the stator easily, but in different models of angle grinder in its own way.

  • Remove the gearbox of the angle grinder;
  • remove the rotor by first removing the mounting bar;
  • remove the plastic stator guard;
  • unscrew the stator fixing screws in the housing;
  • Remove the handle cover and disconnect the power wires to the stator;
  • Remove the stator by tapping on the housing with a wooden hammer or bar.

Repair of angle grinder rotor

Failure of the rotor in the angle grinder is caused by improper use of the tool, frequent overheating, untimely replacement of carbon brushes, abrasive particles and dust getting on the slats of the collector.

First, the length of the spark on the collector increases, then there is the smell of burning and, in the last stage, smoke. A malfunctioning gear unit is accompanied by a knocking or humming noise.

Destruction of even a couple of teeth leads to improper operation of the tool.

You can prolong the life of the rotor by preventing dust from entering the tool, avoiding overheating of the tool, timely change of carbon brushes and lubricants, using only tools with a diameter and diameter recommended by the manufacturer of the power tool.

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