The main spare part of an angle grinder (angle grinder) is a replaceable cutting tool. An abrasive disc that rotates at high speed cuts, grinds or polishes materials. For metal processing, circles are made of abrasive chips, steel milling cutters are used for wood, and metal discs with diamond coating are used for stone. Special nozzles - brushes, petal emery wheels further expand the capabilities of your angle grinder. Next, we will find out what types of disks are, how to properly remove the old one and install a new one, and also consider possible problems arising during the replacement process, and ways to solve them.
Types of discs for grinders: how to choose the right one
The industry produces grinders and discs for them in standard sizes: 115, 125, 150, 180 and 230 mm. Angle grinder from 180 mm is used for cutting stone. The most common size of machines for home and summer cottages is 125 mm, most discs and nozzles are produced for them.
Attention! Always select a disc that matches the size of your angle grinder. You can put a disk of smaller diameter in the angle grinder. But removing the casing and putting in a disk of a larger diameter is extremely dangerous!
We offer to divide the discs according to their purpose: cutting, grinding, sharpening and peeling. Let's consider each type in detail.
Cut-off
We cut through the metal
Inexpensive disk for steel of the Luga plantCutting materials is the most common task in repair and construction, a simple abrasive wheel for metal will easily cut steel bar, roofing iron or plastic. These wheels are made of corundum (crystalline alumina) or electrocorundum (synthetic corundum).
Sawing a stone
The budget disc for stone is produced by the Luga plant To cut stone, we recommend taking a special disc - they use a different abrasive - silicon carbide. He will cope with white silicate brick and slate. But red brick, tiles, and even more so concrete - they won’t succumb to it - you need to take a diamond disk.
Dissolving the tree
These are also available for the grinder Wood cutting blades are very similar to a circular saw blade. Actually, this is a disk for a circular, only a bore diameter of 22.2 mm is suitable for a grinder spindle.
Diamond
As you know, diamond is a very hard mineral, so diamond blades can easily cope with red brick, porcelain stoneware, and tiles. The main material that is cut with diamond blades is concrete.
Diamonds must be handled with care - the disc does not cut steel, it must not be overheated. After two minutes of sawing concrete, the disc will become very hot - take a break. Cooling slots are made around the circumference of the dry cutting disc.
They produce discs for wet cutting of ceramic tiles and porcelain stoneware. Water cools the disc and washes away dangerous dust.
How to choose the thickness of cutting discs
Every craftsman knows that the thinner the tool, the better. Less material goes into chips, it is easier to saw, the cut comes out cleaner.
Discs for angle grinders 115 and 125 mm are produced with a thickness of 1.0–2.5 mm. Discs 150 and 200 mm - 1.8–4.0 mm thick. Pressed corundum powder reinforced with synthetic mesh.
Attention! The thinnest disc (1.0 mm) “walks” during sawing and breaks easily, its pieces fly at high speed in all directions. Don't forget to protect your eyes and hands.
Grinding
The next most important work that the craftsmen entrust to the grinder is grinding and polishing. Similar processing is applied to metal, wood, plastic and other materials.
Petal circle on wood: dozens of emery petals quickly cut chips The choice of grinding discs is very wide. If you are restoring a sideboard, a petal wheel will work to remove layers of shellac. It grips large surfaces and cuts a lot of material in one pass.
The sanding attachment is a plastic circle to which sandpaper is attached with Velcro Another nozzle is screwed onto the grinder spindle. Sandpaper is attached to it on Velcro (Velcro). For coarse processing - P60 or P80, for finer processing - P120 or P180. With a decrease in grain size, grinding smoothly turns into polishing.
Alpaca wool polishing pad Especially for polishing, there are nozzles in the form of pillows, felt or fabric discs. Before work, a polishing paste is applied to them, for example, GOI.
grinding wheels
In fact, there are special machines for sharpening tools - sharpeners. Nevertheless, the rotating disk of the grinder is able to correct a dull ax or cleaver, knife or scythe. Taking into account the wishes of the masters, the industry produces 115 and 125 mm grinding wheels for angle grinders.
Sharpening discs turn the grinder into a grindstone The discs are made of coarse abrasive pressed into a thick plate (more than 5 mm) with a bulge in the center. If you install such a disk on a spindle, the flange hides in a recess and does not protrude above the disk plane. Coarse grinding wheels are also used for cleaning welds.
Roughing brushes and discs
Craftsmen renovating houses from the middle of the last century are faced with the removal of oil paint from the walls. Wire cutters are suitable for this job.
Not a single paint can stand against such a steel cup Korshchetka is a cup, around the circumference of which are steel or brass harnesses. They differ in the thickness and rigidity of the wire - for coarse and fine peeling. The brush is screwed onto the spindle with an M14 thread.
Stone grinding disc cuts old cement evenly After removing the oil paint, the curved concrete wall must be sanded. Only a Bulgarian can cope with such a task. The working surface of the diamond grinding disc is perpendicular to the axis of rotation. Synthetic diamonds cut and smooth concrete like sandpaper on wood.
How to make a replacement
It is already inconvenient to cut with such a disk Discs for grinders are consumables; when cutting, they wear out pretty quickly. A worn disc needs to be replaced. Let's see how to do this using the example of our Interskol-115 angle grinder.
Attention! Before work, make sure that the machine is disconnected from the mains!
Step-by-step instruction
The disc is mounted on the grinder spindle with a clamping flange with an M14 thread. To unscrew the flange, an open-end wrench is included in the grinder kit. Its pins cling to the flange holes.
Open end wrench will unscrew the flange To unscrew the flange, the spindle must be fixed. To do this, a latch is made on the side of the case opposite to the disk. When the button is pressed, the cotter pin enters the hole of the driven disk of the gearbox and prevents the spindle from rotating.
The button fixes the spindle We insert the open-end wrench into the flange holes. With the right hand we press the lock button, at the same time we turn the key counterclockwise with the left hand and we move the flange from its place.
Open end wrench inserted into flange holes Our grinder rotates clockwise. If you have a different direction, remember - you need to unscrew in the direction of disk rotation.
If the flange succumbed, unscrew it by hand, remove and set aside.
Top flange removed We remove the old disk. We don't need it anymore, we can throw it away.
old disk withdrawn Remove the bottom flange.
Bottom flange removed With intensive sawing, hardening is formed from the burnt particles of metal and abrasive from the inside of the casing. Use a steel brush to clean the casing.
The brush cleans the casing We install the lower flange on the spindle, making sure that the flats on the flange coincide with the grooves on the spindle. Put a pad on top.
Bottom flange and gasket installed If gaskets are not attached to your angle grinder, such a washer can be cut out of cardboard or tin.
We put the disk in place, close it with a second gasket.
New disk installed Thanks to the gaskets, if the disc gets stuck in the material and breaks, you can still easily unscrew the flange.
We twist the upper flange by hand against the direction of rotation of the circle (in our case, clockwise), holding the abrasive disc. With your right hand, hold down the lock button and twist it with your hand until you feel resistance. We insert the open-end wrench and twist a little more, no more than a quarter of a turn. It is not necessary to tighten the flange too much, the disc will warp.
Disc replaced, angle grinder ready to go This completes the disc replacement, you can continue sawing. Sometimes when changing a disk, obstacles arise in the way of the master. What to do in such situations - we will consider further.
Video: how to remove the old and install a new disk
Possible difficulties in the process
What to do if there is no key
The open-end key is not tied to the grinder and may well be lost. How to unscrew the flange in this case?
- We make an open-end wrench from a nail. We take a “weave” nail, bend it in the shape of the letter “P” so that the distance between the vertical posts is equal to the distance between the holes in the flange. Cut off the tip and head with a hacksaw. We stick the resulting “key” into the flange holes and unscrew the mount, not forgetting to fix the spindle. If the nut is tightly tightened and there is not enough finger strength, we insert another nail between the vertical segments - the lever will be larger.
- We use the gas key. We take a large pipe wrench, it is also called "gas". With such a tool, plumbers twist steel pipes. We part the key so that it clasps the entire flange. We try to move the nut from its place, securing the spindle. The gas key has a huge shoulder. If you apply force, the spindle lock will break.
- Knocking out the nut. Take a metal bar or a thin chisel. Fix the spindle. Tap the edge of the hole in the flange in the direction of rotation of the disc. So you can move the nut out of place. This method is not the safest: the tool damages the flange and breaks the key holes.
Disc broke, flange jammed
Let's imagine that the master makes an anvil from a steel rail, cuts out the point with a grinder. The disc is skewed in the material and jammed. The motor continues to run and tightens the flange tightly. All work has stopped. How to change the disk, if now it does not unscrew?
- We disassemble the gearbox. We unscrew the mount and remove the gearbox housing. We hold the spindle shaft with a gas wrench or pliers, twist the flange with a horn or other gas wrench. The disk is not affected by this method, you can remove the normal one, good drive. The method works even if the spindle lock is broken.
- We use two gas keys. The method does not require parsing the grinder. Carefully break out the rest of the disk to get to the bottom flange. With the first gas key we clamp the upper flange, with the second key we hook the lower one. We turn in opposite directions.
- We heat the nut with a torch. We heat the sunken nut with a portable gas burner. The nut will expand from heating and can be easily unscrewed.
- Cut the flange with a hacksaw. Some craftsmen prefer to cut the stuck flange with a hacksaw. The method is barbaric - you have to buy a new nut.
- Lubricate threads with penetrating lubricant. Spray the stuck nut with WD-40. It penetrates into narrow gaps and threaded connections. After a five-minute break, try to move the nut with a wrench.
- Cut out the rest of the disk with a hacksaw. We break the disk with pliers, while it is possible. We remove the protective cover, insert a hacksaw into the slot and cut out the remnants of the abrasive wheel. Delicate and reliable method. It does not require parsing the grinder and hard impacts on the tool. The master must have patience, as the method will take up to an hour. The abrasive quickly erases hacksaw blades, they will need several pieces. The advantage is the preservation of the guarantee for the angle grinder, there is no risk of breakage. These circles ensure that the flange does not get stuck.
Such discs can come with a grinder or you can cut them yourself.
Factories produce thin and thick abrasive discs, metal cutting wheels, and nylon brushes for angle grinder spindles. All these spare parts turn the angle grinder into a universal tool and reveal its capabilities from an unexpected angle. For example, a grinder turns into a grindstone. It is not difficult to change the disk, but the master must be aware of some features of the process in order not to get into a difficult situation.
LBM, or as it is called more popularly and popularly Bulgarian, in our time is indispensable and very useful tool. Without him, neither here nor there! And if it suddenly fails, then you have to dodge in every possible way, look for alternatives and think about restoring the instrument. At the same time, it is impossible to use the grinder for its intended purpose due to a seemingly simple overlay when the disk is not unscrewed. Rather, the nut that holds this disk is not unscrewed. Here you can “break wood”, namely, bend or break the key, damage the lock button, break the case, but still not unscrew the very ill-fated nut. So, we will immediately warn you, if it is not too late ... If you suddenly do not unscrew the nut holding the disk with a key, then you need to change tactics. And it is precisely the cardinal method of unscrewing that our article will be devoted to.
Why bites the nut on the grinder that holds the disc
I will tell, perhaps, a well-known truth. It bites nuts more often on grinders with a disk size of a significant size, say 150-180 mm or more. The thing is that the resulting torque, in the event of a disc impact at the moment the cutting starts, is much greater than for a disc, say 125 mm. As a result, the nut is tightened by inertia so much that it is torn off with ordinary and in the usual ways quite difficult. Now for the special ways.
How to unscrew the nut of the grinder disk (angle grinder) if it is bitten
So, if there is no way with the key, even if you insert it and lightly hit it with a hammer, then we begin to use something more serious.
The first thing you can try, but again without fanaticism, is to take a rod, insert it into the holes on the nut and use a hammer to move the nut in the direction of its unwinding. The main thing here is not to break the button and not to break the holes, as here
The second thing that many people advise is to heat the nut. Warm up the nut. As a result, it is a little, but physically still obliged to expand. Resizing may or may not help...
It is not necessary to pull to the extreme until the stopper of the hold button from scrolling or the button itself bursts. In this case, it is not the tool that you unscrew that breaks, but often the angle grinder housing.
The third method is the most effective, and oddly enough, one of the safest for the grinder herself.
We take off the edges of the disk along the nut.
Next, we use a thin metal plate or another disk (thinner), and perhaps a second grinder with a disk. In this case, the broken disk must be machined either with a plate or with a disk. We try to sharpen the disk so as not to damage the nuts holding this disk, because they will still be useful to us. So we grind the whole broken circle until we grind it off and the nut is unscrewed.
This is a matter of 4-5 minutes, no more.
If you will be using a second disc or metal plate, it is best to insert them into a vise to hold them. Since it is dangerous to hold such objects with your hands. This is the most efficient method!
How to make sure that the nut with the disc on the grinder does not bite
And a few words about preventing such unpleasant precedents from happening again. You can use small spacers made of cardboard, inserting them between the disc and the nut. As a last resort, we use a smaller diameter disk, unless of course the nut is screwed on top. As a result, it will be possible to unscrew such a nut without problems. She will not be clamped, she will bite on the thread ...
And another small video on the topic, about the problem that I learned from my own experience.
Angle grinder (popular name - "grinder"), the most common tool for home craftsmen after an electric drill.
Despite the ease of use, "amateurs" often have questions about tool maintenance, especially in emergency situations. As a rule, breakdowns occur due to improper use of the tool.
The main types of angle grinder applications
It is with such nozzles that emergency situations most often occur.
Let's take a closer look at cutting wheels
The question of which side to put the disc on the grinder does not have a correct answer. Abrasive wheels do not have a programmed direction of rotation, so it doesn't matter how you set it. The direction of rotation (away from you or towards you) is determined by the position of the protective cover. The choice depends on the position of the tool that is comfortable for the operator. 
In addition, the direction of the flow of sparks (or stone dust) depends on the position of the casing.
note
It is advisable to put the disc face up (marked) up. In this case, you will not forget which nozzle is installed: for stone or metal. They are not interchangeable.
To install the disk on the shaft, a collapsible flange is included in the kit. Bottom part is rigidly fixed with chamfers, the upper part is a conventional self-tightening nut. It is she who determines in which direction the disk on the grinder should rotate. During operation, the threaded connection is tightened, preventing the nozzle from jumping off. 
Sometimes the kit includes washers-gaskets designed to dampen lateral vibrations. They can be made independently from dense electric cardboard or paronite. 
To fix the flange, a special open-end wrench is attached to the tool. The shaft is fixed with a clamping button to create the necessary torque when tightening.
A variety of mechanisms facilitate our work, both in production and at home. But sometimes they present unexpected and not too pleasant "surprises". After all, it is impossible to foresee all situations in which you will have to use tools.
This also applies to the grinder (angle grinder - angle grinder), when the cutting disc clamps on it so much that it is not possible to unscrew the clamping nut with a standard key or other tools or methods. In this case, there is a danger of breakage of the button for quick clamping of the disk and even the body of the tool, usually made of aluminum alloy. The matter is further complicated by the fact that the surface against which the working disk is pressed is often round and impossible to stop.
Why is the latch nut tightened?
The grinder, depending on the brand and diameter of the working disk, develops from 6,000 to 12,000 revolutions per minute. When the rotating disk sharply touches the surface to be treated, the following fast processes occur.The cutting disc, crashing into the material, experiences great resistance and slows down somewhat, but the rotor of the electric motor rotates for a few more moments by inertia at the same speed and literally screws the spindle thread into the locking nut, pressing it into the cutting wheel. Now it will not be easy to unscrew it, especially with a native key.
Exist various ways get rid of this defect. Not all of them pass without a trace for the tool. Here we will consider one of them, which can be called auto thermal.
How to eliminate the disc clamp on the grinder
For implementation this method you will need some massive wooden material: a piece of thick board, a piece of timber, or just a stump.
Then we take a grinder with a tightly clamped disk, turn on the tool and press the fixing nut against the surface of the stump with sufficient force so that it continuously rubs against the wooden surface.
The process must be continued for two to three minutes. This time is quite enough for the clamping nut not only to heat up, but to become red-hot. If the heating is not stopped in time, there is a risk of damage to the spindle bearing due to overheating.
The degree of sufficiency of the thermal effect on the fixing nut can be checked using a pipette with water: drops from it evaporate instantly, barely reaching its surface.
Next, we proceed in the standard way. We press the button for quick disk replacement and unscrew the nut with a standard wrench without any effort. In this case, we are helped by the well-known property of the metal, to expand when heated.
The nut unscrews with absolutely no extra effort.
The disc should be installed on the spindle with a pattern (marking) outward (towards the clamping nut), since it is on this side that the disc has a wide metal washer. If the disc jams or breaks, the moving clamp will be easier to handle as it will slide on the metal washer rather than the rough surface of the disc.
It helps to put a washer made of cardboard or other not too hard material under the nut. But this method is not specified by the manufacturer of the tool, since this may upset the balance and does not guarantee the reliability of mounting the disk on the spindle.
You can heat the retaining nut with a blowtorch or gas burner. The source of heat in this case does not matter. The main thing is not to overdo it with heating, so as not to damage the spindle bearing.
When working with any mechanisms, you should always expect emergency situations, which are not always possible to solve in accordance with the recommendations of manufacturers. The angle grinder is no exception. When working, you may encounter excessive clamping of the cutting disc. Especially often this problem occurs with large, powerful models, with a power of more than 2 kW. What to do if the disc is bitten on the grinder or the nut is not unscrewed? We will deal with this issue further.
What is causing the problem?
When rotating at idle, it is difficult to encounter a similar problem. Particularly when working with light wheels and tools with a soft start function. However, after an increase in speed and contact with the cut surface, the following occurs:
- When material resistance occurs, the circle sharply decreases the angular velocity of rotation, it slows down.
- By inertia, the engine continues to work for several moments at the same speed, dragging the gearbox and spindle along with it.
- The retainer nut is tightened more strongly by inertia along the thread of the spindle head, thereby pressing the cutting disc.
That's it, the process of tightening the fixing flange is completed - an emergency situation on the face. The following factors influence its occurrence:
- Large circle.
- High tool power.
- Massiveness of the rotor.
- A sharp increase in the depth of cut, i.e. increase in resistance.
In this case, removing the disc from the grinder can be very difficult. Additional measures need to be taken.
Regular disk replacement
Regularly working with angle grinders, you need to constantly change the circles that are consumable. If the tool is already inconvenient to work with, then the worn abrasive wheel should be changed.
Important! Be sure to check the disconnection from the mains to avoid personal injury.
Step-by-step algorithm of actions
The circle is fixed on the spindle head with a fixing nut having an M14 thread. In the standard configuration there is an open-end wrench with special protrusions for hooking with the holes of the fixing flange.
To unscrew the nut, you need to fix the spindle. For these purposes, there is a special latch located on the back of the grinder. By pressing the button, you will fix the gearbox with a cotter pin, eliminating the possibility of its rotation.
Insert the key into the holes. Hold the latch with one hand, and turn the wrench counterclockwise with the other, shifting the nut.
The direction of movement of the disk is usually clockwise. However, there are models that may be different. In any case, unscrewing occurs in the opposite direction to rotation.
When the nut is shifted, it can be easily unscrewed by hand.
Remove the retainer and the old circle.
Remove the bottom flange.
After intensive work with a tool with metal inside the casing, a layer of burnt scale with abrasive can be detected. Use a steel brush to remove residue.
After cleaning, install the lower flange in place, while aligning the grooves of the spindle with the grooves of the flange. A gasket is placed on top.
If your model does not have additional spacers, then such washers can be prepared from plastic or thick cardboard. Next, you need to correctly put the disk on the grinder and close it with a similar gasket.
Important! Installable gaskets make it easy to unscrew the nut, even if the disc is jammed or broken.
Turn the top lock counterclockwise (counter-rotation) by hand while supporting the cutting wheel. At the same time, it is also necessary to clamp the spindle lock and tighten the flange to a noticeable resistance. With an open-end wrench, you still hold out with a little effort. Do not over-tighten the mount, otherwise you can overtighten the circle and it will warp.
Stuck nut - how to unscrew?
It is not so easy to remove a disc on a grinder if it is bitten, especially without damaging the cutting element or tool. We will also consider several options for action.
Disc replacement by reverse rotation
This method has several advantages - it can be done without a key and with a broken spindle lock. Beginners in working with angle grinders mistakenly believe that if the stopper is broken, it is almost impossible to unscrew the nut. However, this is not the case. You don't even need keys.
The bottom line is that the abrasive wheel needs to be rotated in different directions. Putting on thick gloves, you need to hit the cutting edge of the circle several times. This is how you provide variable movement in different sides. As a rule, a couple of sharp blows are enough so that the nut can be easily unscrewed.
open end wrench and socket head
In this case, you will have to slightly modify the existing standard tools - an open-end wrench for 17 and a socket head for 24 mm. The thickness of the key is ground down to 4 mm. 4 protrusions are machined on the head, falling into the holes of the fixing nut.
After preparation, the key is placed in the space under the disk, and the head is put on the angle grinder flange and rotated in the opposite direction to the rotation of the circle. After that, it can be easily removed and put a new one.
Heat
This is one way to remove a disc from a grinder without a key. The fixing nut is heated with an industrial hair dryer or a gas burner. After that, the flange will unscrew much easier. However, there is a risk of damage to the plastic parts of the grinder or gearbox.
With a nail
For these purposes, a 100 mm nail is best suited. It should be bent into a U-shape so that the ends fit freely into the holes in the clamping flange. The tip and cap are removed. By inserting a nail into the holes, the latch is turned away. If the efforts of the hands are not enough, then add a nail or a screwdriver in the form of a lever.
With a gas wrench
The use of this tool is justified by the increase in the applied moment of force due to the increased shoulder. It will be much easier with a gas wrench to unwind a jammed connection. However, when dealing with jamming, it is important to remember that applying excessive force can damage the spindle lock or clamp nut.
Perforator or drill in chiseling mode
You can unscrew the disc on the angle grinder without a key using a drill or puncher, after switching it to the jackhammer mode. A suitable drill is used as a working nozzle, most often 6 millimeters. Rest the drill against the edge of the hole of the clamping nut, fix the movement of the spindle and briefly turn it on to move it. This method allows you to turn away even very complex bites.
Nut tapping
This method is similar to the previous one, only you can use a suitable metal rod or chisel. With the spindle head fixed, tap along the edges of the clamp holes in the direction of the wheel movement. Slightly moving the latch off the dead center, you can unscrew it with your hands. However, the method is not the most harmless for the tool - the mounting holes for the standard key are damaged.
Destruction of the cutting wheel
You can unscrew the jammed nut by completely destroying the disk. If there is already damage, then you can break it with your hands, but most often this will not work. It is better to take a hacksaw or a metal blade and cut it. As a result, you will be left with a central ring and hard-to-reach pieces. Having found a suitable plate, holding it in a vice, grind off the remnants of the abrasive on it to a metal ring. After that, it will be easily unscrewed with a standard key.
by the most in a radical way unscrewing the jammed clamping nut is to cut it. It is advisable to resort to 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 for spare clamping elements to be included in the delivery set of the angle grinder.
Measures to avoid jamming
Taking care of the safe operation of the angle grinder in advance, you will save yourself from the need to take measures to eliminate an emergency situation. Such activities include:
- Inserting cardboard or plastic washers between the disc, flange and spindle head. They do not allow the tool to jam, but even in the case of a corkscrew, they can be removed / melted and the element can be easily unscrewed.
- The abrasive wheel must be set correctly. To do this, put the front side of the circle on the support flange (picture to the gearbox). It must not come into contact with the clamping nut. In this case, the standard metal ring in the center will act as a washer to prevent jamming.
- Weld a regular nut onto the clamping flange, which allows you to press mounted drive with a regular wrench.
- Control tightening force. No excessive force is needed to install the cutting element. Otherwise, it will jam under heavy loads.
Safety regulations
When working with a grinder, it is important to remember that this tool has an increased risk of injury. Accordingly, it is impossible to lose vigilance in any case, even when disconnected from the mains. When using auxiliary tools and materials to replace the disk, be careful with them. Hand tools can also cause significant injury.