How to unscrew the brush from the angle grinder. How to remove without a wrench?

How to remove the disc from an angle grinder without a wrench

When working with any machinery, you should always expect abnormal situations that can not always be solved in accordance with the manufacturer’s recommendations. An angle grinder is no exception. When working, you may encounter excessive clamping of the cutting disc. This problem is especially common with large, powerful models, over 2 kW. What to do if the disc on the angle grinder is jammed or the nut does not unscrew? Let us deal with this issue further on.

When rotating at idle speed, it is difficult to encounter such a problem. Especially when working with lightweight wheels and tools with soft start function. However, after increasing the revolutions and contact with the surface to be cut, the following happens:

  • When material resistance occurs, the wheel has a sharp decrease in angular velocity of rotation, it brakes.
  • The motor coasts for a few moments at the previous speed, dragging the gearbox and spindle along.
  • The retaining nut is tightened more by inertia on the thread of the spindle head, thus 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:

  • Big wheel size.
  • High tool power.
  • Massive rotor.
  • Sharp increase in cutting depth, t.е. Increase in resistance.

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

What is the cause of the fault?

How to eliminate the disk clamping on the angle grinder

To implement this method you need some massive wooden material: a piece of thick board, a piece of wood or just a stump.

Then we take the angle grinder with firmly clamped disk, turn on the tool and with sufficient force press the fixing nut to the surface of the stump, that it continuously rubbed against the wooden surface.

The process should continue for two to three minutes. This is just enough time for the clamping nut to become not only hot, but also glowing. There is a risk of damaging the spindle bearing due to overheating if the heating is not stopped in time.

You can check whether the thermal impact on the retaining nut is sufficient by using a dropper with water: drops will instantly evaporate as soon as they reach the surface.

Then proceed in the standard way. Press the quick-change button and use a standard wrench to loosen the nut without any effort. In this case we are helped by a well-known property of metal to expand when heated.

Changing the disk in normal mode

Regular operation of the angle grinder requires the disc, which is a consumable, to be replaced at all times. If the tool is no longer comfortable to use, the worn grinding wheel must be replaced.

Important! Be sure to check the disconnection from the power grid to avoid your own injury.

Step by step procedure

The wheel is fixed on the spindle head with the lock nut, which has a thread of M14. There is a ring spanner with special hook lugs for engaging with the holes of the locking flange as standard.

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Unscrew the nut by securing the spindle. For this purpose, there is a special lock located on the back of the angle grinder. The cotter pin can be pressed to lock the gearbox, so that it cannot rotate.

Insert the wrench into the holes. Hold the retainer with one hand and turn the wrench counterclockwise with the other, sliding the nut.

The direction of movement of the disc is usually clockwise. However, there are models that may have a different. In any case, unscrewing works in the opposite direction to the rotation.

When the nut is slid, it can be effortlessly unscrewed by hand.

After intensive work with the metal tool, you can find a layer of burnt scale with abrasive inside the casing. Use steel brush to remove any residues.

After cleaning, reassemble the lower flange in such a way that the grooves on the spindle and the grooves on the flange are aligned. A spacer is placed on top.

If your model has no additional gaskets, then similar washers can be prepared from plastic or thick cardboard. Next, you need to put the disc properly on the angle grinder and cover with a similar gasket.

Important! The spacers fitted allow the nut to be unscrewed easily, even if the disc is jammed or has broken.

Turn the upper flange in counter-clockwise direction (counter-rotation), supporting the cutting wheel with your hand. Also clamp the spindle lock and tighten the flange until you feel resistance. Use a wrench to tighten with a little more force. You should not overtighten the mount, otherwise you can overtighten the wheel and it will warp.

Now you can continue to work. However, problems occasionally arise and unscrew the disk on the angle grinder just does not work. How to change the disk on the angle grinder in such cases, let’s see below.

Jammed nut. how to unscrew it?

It is not so easy to remove the disk on an angle grinder if it is jammed, especially without damaging the cutting element or the tool. There are also a few things to consider.

Changing the blade by counter-rotation

This method has several advantages. you can do it without a wrench and with a broken spindle lock. Those who are new to the angle grinder mistakenly believe that if the stopper breaks, it is almost impossible to unscrew the nut. But this is not the case. You do not even need a wrench.

The bottom line is that the abrasive disc needs to be rotated in different directions. Wearing tight gloves, you need to repeatedly hit the cutting edge of the disk. Exactly by this you provide variable motion in different directions. As a rule, a couple of sharp blows are enough to easily unscrew the nut.

With an open-end wrench and socket head

In this case you need to slightly modify the existing standard tools. a wrench for 17 and a socket head for 24 mm. The thickness of the wrench is ground to 4 mm. Mould 4 jaws on the head that fit into the holes of the locking nut.

After preparation, the wrench is placed in the space under the disc, and the head is put on the flange of the angle grinder and turned in the opposite direction to the rotation of the wheel. It can then be easily removed and replaced with a new one.


This is one way to remove the disc from the angle grinder without a wrench. Heat the fixing nut with an industrial vacuum cleaner or a gas torch. The flange can then be unscrewed much more easily. However, there is a risk of damaging the plastic parts of the angle grinder or the gearbox.

Using a nail

A 100 mm nail is best for this purpose. It should be bent into a U-shape so that the ends fit freely into the holes of the clamping flange. The point and flat is removed. Inserting a nail into the holes unscrews the retainer. If the effort of your hands is not enough, then add a nail or screwdriver in the form of a lever.

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with a gas wrench

The reason for using this tool is to increase the applied torque with a larger lever arm. It will be much easier to unscrew the jammed connection with a gas wrench. However, when removing the jamming tool, it is important to remember that if excessive force is applied, there is a risk of damaging the spindle lock or the jam nut.

Use a rotary hammer or drill in chisel mode

Unscrew the disk on the angle grinder without a wrench can be using a drill or a torch, putting it in jackhammer mode beforehand. Use a suitable auger, usually 6 millimeters, as the core bit. Place the drill against the edge of the hole in the clamping nut, block the movement of the spindle and move it backwards with a brief actuation. This method allows you to unscrew even very complicated bites.

Knocking out the nut

This method is similar to the previous one, but a suitable metal bar or chisel can be used. Having secured the spindle head, tap on the edges of the clamping holes in the direction of movement of the wheel. Slightly moving the clamp from the dead point, you can unscrew it by hand. However, this method is not the most harmless for the tool. the mounting holes for a standard spanner are damaged.

Destruction of the cutting wheel

It is possible to unscrew a jammed nut by completely destroying the disk. If it is already damaged, you can break it off by hand, but more often than not you won’t be able to do it. It is better to take a hacksaw or metal blade and saw. This will leave you with a center ring and hard to reach pieces. Find a suitable plate, clamp it in a vice and grind the abrasive residue against it until it reaches the metal ring. After that it can be easily unscrewed with a standard spanner.

The most radical way to remove a jammed jam nut is to saw it out. It is advisable to use it only in extreme cases. Of course, you can find a new one, but you will have to spend your time and money. It is not uncommon to have spare clamping elements in the delivery set of the angle grinder.

Types of angle grinder discs

Angle grinder is widely used in construction and repair technological operations. Discs for the angle grinder differ from each other:

The choice of discs for the angle grinder involves knowledge and consideration of not only the machined workpieces, but also the capabilities of the tool itself.

Cutting-off wheels

The most commonly used discs for angle grinders are also called abrasive discs. They are classified according to different characteristics. There are discs for working with metal, stone, wood. There is also a diamond disc that serves to work with the toughest and hardest materials (reinforced concrete, ceramic granite, tile, marble, granite and other natural and artificial stones).

Let us give a brief description of each species.

The common feature of all severing discs is classification by outside diameter and thickness. Outer diameter comes in:

  • 115 mm for small domestic grinders;
  • 125 and 150 mm for medium power and weight angle grinder;
  • 180 and 230 mm for powerful professional tools.

Disc thickness ranges from 1 to 3.2 mm. It depends on the size of the nozzle: discs with a large diameter have a large thickness; discs of medium and small. any thickness. The choice of disc thickness is influenced by:

Cutting (abrasive) discs for metal

These wheels are used to work with sheet body steel (disk thickness from 1 to 1.6 mm) and long steel: rebar, round bars, channels, angles and other types (disk thickness from 2.5 to 3.6 mm). There are special attachments for working with stainless steel, aluminum, cast iron and other metals.

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This is indicated by a marking and a coloured stripe on the surface of the disc. Abrasive discs are several layers of fiberglass mesh, on which bakelite abrasive material (silicon carbide, corundum, electrocorundum) is pressed on both sides under great pressure. The reinforced abrasive discs are then placed in a heat treating oven to get durability. Set temperature of heating. 200 degrees. There the mass is sintered and becomes strong and resistant to splintering.

Abrasive discs for stone

They are absolutely identical to the discs for metal, and differ only in the abrasives used.

For wood

They are made of high-strength steel and have sharp teeth on the outside diameter. These tools work on the principle of a circular saw and are rather dangerous in operation. It is recommended that the angle grinder permanently fixed with a special device.


They are used for cutting high-strength natural and engineered stone materials.

There are different kinds of diamond discs for concrete, reinforced concrete and stone. They differ from each other by fractionality of diamond dusting and type of cutting edge. solid, with large or small cuts, notches. It is important to know that the diamond disc is not used for work with metal workpieces. It is difficult to understand the purpose of diamond discs by their appearance. Before buying, it is best to consult with a sales clerk or carefully study the addendum to the package.

Some manufacturers of diamond discs paint the front side of the disc depending on the material it is designed for:

  • green. for granite;
  • yellow. for plaster and tile;
  • blue. for marble and concrete;
  • Gray. for granite ceramic and tile;
  • orange. for brick.

Diamond discs with segmented cutting blades are used for dry-cutting rocks. Grinding wheels with a solid cutting edge requires water cooling. Turbodiscs with slots in the wheel body operate at higher rotational speeds than discs with a segmented blade.

Grinding and Roughing

Grinding wheels are divided into four types:

    Finishing (sanding) discs remove old paint, primer or varnish, and sand wood.

  • Remove rust and tough dirt with special wire wheels.
  • Bowl-shaped diamond modifications are used to polish stone workpieces.
  • Disc discs of plastic or rubber are used to polish metal surfaces. Interchangeable disks with sandpaper, felt, sponge, cloth can be mounted on plates.
unscrew, brush, angle, grinder, remove, wrench

Most grinding discs work with special pastes or liquids that include the finest abrasives. With these nozzles are ground surfaces of any material, including auto body parts in car repair shops.

Electric graphite brushes (carbon brushes, EG brushes)

Mark Hardness Specific electrical resistance, μOhm Coefficient of friction, not more Current density, А/cm2, not more Pressure on brush, kPa Linear speed, m/s, max
1 2 3 4 5 6 7
Carbon brushes


EG14 BDX-14



EG841 EG84 UMK

What to do to prevent this from happening again?

In order to avoid this situation again, you can put a plastic, paper or cardboard washer under the nut before clamping the new disk. And in this case the nut can always be unscrewed without any problems.

Cutting stones or discs are not always of proper quality nowadays and breakage is a frequent problem. Of course, the human factor of improper operation can not be excluded. But now, if you find yourself in a similar story. you know what to do. Till next meetings!

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