Which side to put the cutting disc on the angle grinder

How to properly place a disc on an angle grinder?

The disc of the “angle grinder” (angle grinder) is one of its main working parts. It is the disc that determines the use of the instrument. With it, this machine can be used to cut, grind or polish various materials. Discs, depending on the purpose, differ from each other: from abrasive chips. for metal, steel milling cutters and circular saws. for woodworking, with diamond dusting. for stone and tiles, all kinds of brushes, brushes and emery wheels. for polishing various surfaces.

The disc of the “angle grinder” is a consumable material; you cannot save on it in the process of work. The disc will gradually wear out (burn out) and must be replaced. When planning work, you need to be prepared for this and it is better to stock up on several removable disks in advance.

How to change a disk if it is jammed?

What to do if the wheel on the “angle grinder” is stuck? This can happen, for example, when, as a result of work, pieces of the workpiece being cut sharply clamp the rotating disc. This often leads to its destruction.

To unscrew the nut tightened as a result of rotation, if the circle is bitten, it can be very difficult.

  • One of these methods would be to use two gas keys at once. In this case, the remains of the disc must be broken with pliers. With one key, you need to clamp the part of the stem located under the disc, and with the other, unscrew the flange.
  • Sometimes, in order to gain access of the gas wrench to the rod of the “angle grinder”, you have to disassemble the gearbox.
  • A simple device saves from the problem of a jammed nut. cardboard or tin washers. They are often sold with an “angle grinder”. But over time, they can be lost or become completely unusable. Making homemade washers is not at all difficult. However, it is better not to neglect them.

In extreme cases, the flange can be sawn with a hacksaw for metal and then replaced with a new one.

How to remove it?

Discs, especially those designed for cutting, burn out quickly and have to be replaced.

It will be useful to remind once again about the need to disconnect the “angle grinder” from the network. Work to be done with fast rotating parts and better protect yourself.

If you need to replace a worn disk, you need to perform a number of simple operations.

  • The disc is secured to the stem stem with a threaded nut. In the kit of any angle grinder there is a special key, on the arms of which pins are fixed, which cling to the holes of the flange.
  • The spindle is fixed with a special button, the cotter pin of which, when pressed, enters the hole of the gearbox, thus fixing it. Having pressed the button with your right hand, at the same time with your left hand you need to unscrew the fastening nut with a wrench. If the nut has moved from its place, unscrew it by hand. That’s it, now the disc can be removed.
  • There are times when the key, for some reason, was not at hand. What to do? The easiest way out is to stop working. But, as they say, this is not our method. It is also possible to unscrew the clamping nut of the “angle grinder” without a key. Often a pipe (gas) wrench is used for this. On such a key there is a device that spreads it. It is necessary to tighten the nut and, fixing the gearbox of the “angle grinder” with a button, move it from its place. Then it can be unscrewed by hand.

cutting disc safety basics-How to properly use an angle grinder with cutting disc

  • There are holes in the nut for fixing it with pins on the key horns, you can unscrew it by tapping with a hammer on a chisel or a bar that is pressed into the hole.
  • It is sometimes possible to push the nut off by simply tapping its edge with a hammer in the direction of twisting. However, in this case, damage to the flange may occur, especially the holes for the pins of the key; in the future, it may be impossible to apply the key to such a nut.
  • A very good result is obtained when using a nail to make a key. It is better to choose a large nail, from 100 mm. Using a hammer and pliers, the nail is U-shaped. With a hacksaw or chisel, the point and head of the nail are cut off. With such an improvised wrench, you can try to knock off the nut. You can bend the ends of such a key, then it will turn into a kind of open-end key, but this will require a lot of labor. You can also insert a gate, for example, a hammer or other nail, into the arc formed by a bent nail.

How to install correctly?

Installing a disk on an UMSH is not so difficult. You can change it simply by following the instructions, although there are some nuances here.

First of all, you need to install the disc in the correct direction. This is especially important if it is detachable. Usually the side of the disc with the label on which the marking is indicated and, accordingly, the scope of its application, is slightly different from the opposite side. It may not appear immediately, but with prolonged intensive work, the difference will not only be noticeable. it will be obvious.

On the side on which the label is glued, a wide pressure washer is placed, and the movable nut acts on it when tightening (installing the disc). The nut slides on the polished surface of the washer, without it it will become more difficult to tighten or unscrew, since the abrasive will firmly hold the nut and more effort will be required. This is especially important if a quick replacement of the disc is required or if it breaks down (jamming).

There is always a chance of disc failure, but installed correctly, it breaks only under heavy loads, the structure of the discs takes into account the difference in loads on both sides.

With circular saws or other products that have teeth or a significant difference in two sides, there is usually no problem how to set. For example, a grinding disc cannot be fixed on the contrary: it will simply be impossible for them to work.

Discs for stone, including diamond ones, have a special rotation indicator in the form of an arrow: when installing them, you need to fasten them taking into account where the rod will rotate.

It is also important to consider the size of the disk when installing. In no case should you neglect safety and remove the protective cover. it is better to choose a disc of the appropriate diameter. Sometimes a worn-out disc from a large unit is placed on a smaller “angle grinder”. However, a worn disc, as a rule, cuts worse, the working surface is limited to about half the radius of the disc, the structure is slightly different. The disc burns faster and does less work. This operation can be justified if the diameter of the stem is the same. But you won’t be able to change it back.

Debris must not fall under the disc during installation. Of course, the clamping nut may well squeeze small objects, something will press into the surface of the circle. But an imperceptible skew will cause a displacement of the plane of rotation and, as a result, a strong vibration of the entire mechanism, it can cause the destruction of the disc and, of course, you should not hope for an accurate cut in this case.

Before installing the disc, the “angle grinder” must be disconnected from the mains. this is the main safety requirement, since a sudden turn on at this time is fraught with serious injuries.

The clamping nut must be unscrewed with the wrench supplied with the tool. To prevent the stem from spinning, it must be locked by pressing a special button. It is necessary to unscrew the nut while keeping the button pressed.

After twisting the nut, the disc is put on the released stem, with the front side out, and you need to make sure that it is installed exactly in the seat.

The kit for the new “angle grinder” always includes a certain amount of cardboard spacers. when installing the disc, they must be laid so that they are between the disc and the clamping elements. These gaskets will help unscrew a broken or jammed disc.

Further, the nut is manually tightened up to the stop and tightened with a special wrench. That’s it, the “angle grinder” is ready to go.


If you had to use a gas wrench, you must remember about the very powerful shoulder of such a wrench and about the effort that is applied to the parts of the “angle grinder”. If you do not act carefully, the spindle lock could be ripped off or the gearbox could be damaged.

All manipulations with the disc of the angle grinder must be carried out with the power supply completely disconnected (the plug must be removed from the socket). Any inadvertent pressing of the start button will cause the electric motor to turn on, and the rod rotation speed is very high. In this case, injuries cannot be avoided.

Working with an “angle grinder” involves a lot of waste in the form of metal or wood shavings and dust. Before starting work, you must wear special safety glasses: they will protect your eyes from fragments of the cutting wheel itself in the event of its jamming and destruction.

Glasses are needed not only as a safety element. If the eyes are protected, more attention can be paid directly to the work of the “angle grinder”, to ensure the correct cut or the choice of the correct mode of operation. This will allow the most efficient use of consumables (cutting wheels), minimizes the occurrence of abnormal situations with a biting disc or its destruction.

A protective mask that completely covers the face will perfectly replace glasses. this is especially important for a visually impaired master who wears diopter glasses, on which safety glasses cannot be worn.

The disc on the “angle grinder” can be installed both “away from you” and “towards you”, depending on the direction of rotation and, accordingly, the flow of chips. This does not make a fundamental difference in work. However, the “angle grinder” with a circle “towards itself” when biting the disc tends to jump out of the cut forward, and not on the one who uses it. This is especially important when working with powerful tools, but even a small angle grinder can be a serious hazard.

A specially mounted extension cord with a plug socket, preferably without grounding, will help to quickly stop the operation of a machine that has escaped from the hands.

“Angle grinder” is a rough processing tool and it is not worth striving to obtain an ideal surface as a result of its work, the main thing is to make a rough cut, which later, if necessary, can be processed in other ways.

To work without clamps and jamming, it is better not to cut long metal workpieces to the end, leaving 1–2 mm of metal in the cut: they will be easy to break off afterwards, this will practically not affect the quality of the workpiece.

It is better to place small workpieces in a vice or press them with a clamp to a workbench or other reliable horizontal surface. The quality of the cut and safety depend on the density of pressing.

How to put the disc on the “angle grinder” can be seen in the following video.

How to Install the Cut-off Wheel on an Angle Grinder Correctly

For several years I have been using an angle grinder in my summer cottage, and all this time I have no answer to two questions: which side to put the cutting wheel, and in which direction it should rotate. “I shoveled the entire Internet,” but I could not find a definite answer to these questions. The opinions were divided equally. Both sides give convincing arguments, but at least some authoritative official documents on this topic are silent. Manufacturers are also silent. Today I want to speculate a little on this topic in order to still decide, for a start, with the first question.

So which side to put the cut-off wheel on the angle grinder?

Essence of the question. In the center of the circle (cutting or grinding) there is a galvanized steel ring, which has four punched holes around the circumference, as a rule, with the edges crushed down, to prevent this ring from turning relative to the abrasive. The inner edge of the ring is wrapped inside the circle, into its central hole, and ends flush with the opposite surface of the circle, without going out onto it.

According to manufacturers, this ring is made to protect the shaft that rotates the grinding wheel. “With a high degree of probability,” this is its main function, otherwise the abrasive, when the disc is rotating, will wipe the groove on the shaft of the angle grinder over time, and it will be impossible to center it. Note that in the production of wheels, the ring is riveted during the pressing of the disc from above, after the whole cake of mesh and abrasive has been formed. So, it does not carry any technological function, as it slipped somewhere in the Комментарии и мнения владельцев from an “authoritative” source. I looked at a number of different rollers for the production of wheels, and everywhere the technological process was approximately the same. the ring was pressed into the disk from above already during the compression of the formed disk by the press.

The ring is usually located on the label side of the circle. However, there are circles in which the ring extends to both sides of the circle, and on some circles with a sunken center, it is located only on the side opposite to the label and is located on the sunken side. That is, manufacturers mold rings in different ways. Although, it must be admitted, most of the cup circles still have rings on the convex side, which is “kakbe hint”, that it is preferable to put the discs ring down.

At the very beginning, after buying an angle grinder, I intuitively put the circle with the label out. On that circle, the metal ring in the center was also pressed from the side of the picture. So I sawed, and did not experience any problems. But then I had a cup-shaped circle (with a recessed center), and in it the picture and the ring were on the convex side. I put it with the picture facing out, and it turned out that the circle was scraping on the protective casing. I had to turn the circle over. That’s when I had this question for the first time

The other day, while watching videos about tools on YouTube, I came across a discussion of this issue, and decided to find out for myself how to set the circle correctly? As I mentioned above, opinions on the Internet are equally divided on this issue. Then I began to develop my own point of view.

Rings on circles, including cup rings, are molded from different sides, although more often they are on the convex side from the side of the label.

The circles do not indicate the direction of rotation.

These points tell us that “with a high degree of probability” circles can be placed by either side.

Next, I carefully looked at the washer and nut, between which the disc is attached to the shaft of the angle grinder:

On the left is a washer that slides over the shaft. It has a ribbed surface and a rubber ring at the inner edge. On the right, the nut, although not polished, has a rather smooth surface, which lies up in the photo. The circle should be clamped between them. At first I thought that the ribbed surface of the washer seemed to be created for engaging the abrasive, and the smooth nut should slide well on the ring so that you can easily tighten it. But the rubber ring was a little embarrassing, which was clearly made in order to cling to a smooth surface, and would probably deteriorate if the sharp edge of the hole from the abrasive side had to be pressed against it often.

I tried this and that, and so, insert the disc between the washer and the nut, and twist the parts with my hands in order to understand in which case which part clings to the disc better. So, a washer with ribs and an elastic band in any case clings to the disc better, even by the ring, but the nut slides even on the abrasive. I also noticed that it is easier to put the circle on the washer with a ring, since there are burrs on the side of the abrasive that prevent the hole from being loosely put on the neck of the washer. So the results of these experiments clearly support the ring-down setting of the circle on the puck. That is, label down.

I noticed one more nuance. The clamping surface of the quick-clamping nut has a significant backlash relative to its thread, which allows it to press the wheels, even if there are abrasive irregularities on their surface. In this case, such a disk will be pressed flat. If you turn it over, then it will lie on the washer with an abrasive at a certain angle, and it will have a lateral runout. This is another argument in favor of setting the circle with the ring down, towards the washer.

Everything that I have listed above follows only from design features. Now a few words about practical convenience.

Not all angle grinders have a quick-locking nut like mine. If this is a simple nut with wrench holes, then it is easier to tighten it not with a wrench, but with the circle itself. It will be easier if the abrasive clings to this nut. That is, in this case, the circle should also be installed with the ring to the washer. They also say that if the nut adheres to the metal ring, and when biting the circle it clamps, then it becomes much more difficult to unscrew it than if it adhered to the abrasive that is crumbling by nature.

In general, after much thought, I came to the conclusion that a flat circle should be placed with the ring down, to the washer, and if the disk is cup, then there is only one position it can be placed, regardless of which side it will have ring.

el_pir sent me a manual for the Metabo WP 850 angle grinder, which says in black and white:

At the same time, there is no clarification whether this refers to cup circles, or flat. Just detachable. Therefore, to all cut-off. This fully confirms my point of view. Also, in all instructions for Metabo grinders, the corresponding figures are given (although only cup circles are shown there):

Well, the main picture on the covers of all Metabo grinders’ instructions is also kakbe hint (although the circles there are also cup):

I think the author is most likely interested in the question, “which side to put the disc on the angle grinder (angle grinder)?” which interests many.

Regarding the algorithm for replacing the disk, questions rarely arise, here what is called everything in plain sight. a special key or a gas key and off you go. It is also difficult to overshoot with the size of the disc, here the size of the casing acts as a criterion. An important parameter is the number of revolutions indicated on the disc, here it is necessary to choose strictly in accordance with the manual of the angle grinder, the disc of which revolutions can be used on it (the revolutions indicated on the disc must be either equal to or greater than the spindle revolutions, but in no case not less!)

I will not speak about bowl-shaped discs. you cannot put them in another way. Diamond discs and discs for cutting stone from carbide, have an indicator of the direction of rotation, or a pronounced tooth profile, in addition, they have a metal base. and it is metal on both sides.

But in which direction to put the label of the cutting disc during installation, not everyone knows. outward or to the gearbox with a piece of paper.

Some are simply convinced that there is no difference. But this is not the case. The disc is always placed with the label facing out. Yes, someone will say that the direction of rotation of the disc is not regulated by a strictly drawn arrow, almost always this arrow is not there, at least on abrasive discs (cutting) and will also be right.

Here the point is different, an arrow is not needed, at least according to several following logical conclusions.

A wide metal washer is installed on the side of the label. That is exactly what it should be facing the movable flange nut, that is, outward (even if the disc is without a label). If the disc is jammed and broken, it will be easier to unscrew the movable nut if it slides over the metal washer. If you put the disc on the contrary (with a washer to the gearbox), then the movable outer nut will be very difficult to unscrew along the abrasive part.

In connection with this seemingly obvious thing, the structure of some cutting discs is performed. They are less susceptible to breakage (and wear), if installed correctly. with the label outward (respectively, and with a wide washer to the clamped nut and not towards the gearbox)

P.S. Well, and certainly, in addition to all of the above, for work you need to arm yourself with a suit made of dense fabric (I have a canvas apron for this purpose) and goggles!

How to put a circle on an “angle grinder”?

Fastening the circle to the UMSH is not a very difficult process. It is easy to change it, you just need to look at the instructions, although there are some difficulties.

The first thing to do this is to secure the circle on the right side. Always the side of the circle with the emblem, on which the marking is visible and, accordingly, the area of ​​its use, somewhat different from the opposite side. Understanding will come, but with long work.

From the side on which the emblem is glued, the washer is pressed, and the nut acts on it when the circle is secured. The nut travels along the polished area of ​​the washer, without it it will become more difficult to tighten or unscrew, since the abrasive holds the nut tightly and strength is needed. This is necessary if you need to quickly change the circle or it has become faulty.

Wheels for working on stone surfaces have a special rotation indicator in the shape of an arrow: when fixing them, you must take into account which direction the rod will turn.

When securing the circle, you also need to consider the diameter of the circle. There is no need to ignore safety precautions and disassemble the protective cover. It happens that a circle from a large apparatus is installed on a small-sized “angle grinder”. However, such a circle usually works poorly, the working area is limited to somewhere in the half radius of the circle. The circle becomes unusable faster and does less work.

When fastening under the circle, there should be no debris. Usually, the nut can press small parts, the rest will go into the surface of the disc. But an invisible skew can cause a tilt of the plane of rotation and, as a result, vibration of the entire mechanism, it can cause damage to the circle. there is no need to hope for an accurate cut.

Before fixing the wheel, the “angle grinder” must be disconnected from the network. this is the main safety rule, since an unexpected start at this time can lead to injury.

The clamping nut must be unscrewed with the supplied wrench. In order for the stem to spin. it must be stopped by pressing the special button. Unscrew the nut at the same time holding the button down. Further, after unscrewing the nut, a circle is attached to the free rod. back side out, and watch out. so that it is fixed exactly in the seat.

Installing a wheel on an angle grinder does not require special skills, but you need to know some rules.

And what advice will you give on how to correctly put the circle on the “angle grinder”. Share your experience in the Комментарии и мнения владельцев.

Prescribing instructions

The instructions for many angle grinders, such as the Metabo WP 850, clearly state that “the metal flange of the abrasive cut-off wheels must be in contact with the support flange”. Manufacturers do not give such recommendations in vain, since they ensure safe operation of the tool, reduce the risk of serious injury to the master.

Guaranteed even installation on the shaft

The metal ring increases the footprint. Therefore, when the disc is installed on the shaft and starts to tighten with the nut, the pressure is evenly distributed. This ensures a smooth fit of the cut-off wheel and reduces the likelihood of damage from skewing.

Which side to put the cut-off wheel on the angle grinder

Angle grinder (angle grinder) or, as it is also called, “angle grinder” is a widespread tool with which craftsmen saw, cut, grind various kinds of surfaces. During work, it is often necessary to replace the working disk. And at this moment, many people have a question about which side to put the cutting disc on the angle grinder.

Why do you need a metal ring

The metal washer (ring) is designed to protect the integrity of the disk when it is tightened with a movable flange nut, as well as to increase the bearing surface area. In addition, the metal washer does not allow the cutting disc to “stick” to the nut surface, which greatly facilitates the process of its replacement.

Ease of disk installation

Installing the abrasive wheel face-out provides another advantage. you will always visually see which nozzle (for metal or stone) is currently installed on the angle grinder. They are not interchangeable and, if mistaken, there is a high likelihood of serious consequences. For example, when trying to use a cutting disc for metal cutting through concrete, it may be destroyed and traumatized by the resulting pieces of the master. Therefore, installing the abrasive wheel with the label facing out will provide not only convenience, but also safety of work.

Advantages of ring-mounted disc to angle grinder

The cut-off wheels do not have a programmed direction of rotation. Therefore, it does not matter which side will carry out their installation. But as mentioned above, installing the circle with its front side outward facilitates the process of replacing it (it is much more difficult to unscrew the nut on the abrasive side). In addition, such an installation provides several more advantages.

The main difference between the two sides of a circle

On any cutting disc, two surfaces are clearly visible. One of them (back) is monophonic, formed by an abrasive material. The second (front) has a label containing basic information about the characteristics of the disc. But the main distinguishing feature of the two surfaces is the presence of a metal ring on the front side.

How to fit an Angle Grinder blade, label up or label down?

Is there a significant difference from the direction of rotation

The direction of rotation of the cut-off wheel can be both “towards yourself” and “away from yourself”. Each of them has its own advantages and disadvantages. So, when the disk rotates “away from you”, dust and sparks fly to the operator, which creates additional difficulties in work, is associated with possible burns to the eyes, skin, flashing clothes. Rotation of the disk “towards itself” is devoid of this drawback. But in this case, there is also a higher risk of injury. After all, if the disc is clamped, the tool will forcefully fly into the operator’s face. There is no single rule in which direction the cut-off wheel should rotate. If it is important, then the information must be indicated on the instrument. In all other cases, the direction of rotation is selected by the operator, taking into account the type of surface to be treated, convenience and work experience.

Why do you need a metal ring

A washer or simply a metal ring is necessary to protect the abrasive from excessive tightening, since many users tend to tighten the stopper tighter, fearing that the circle will fly off while working with the tool.

Also, the ring is mounted on an angle grinder disc to significantly increase the bearing surface area. In addition, the washer is designed so that the abrasive does not “stick” to the nut, which simplifies the removal process.

What to use to install the disc

The operation is quite simple and will not take more than a few minutes if the correct manual is chosen. But, in order to perform this type of work, you must adhere to the basic rules, and use a special tool.

Having decided on the tools that will be needed for replacement, you can proceed directly to the installation:

How to change the disc on an angle grinder?

  • A metal ring is located on top of the abrasive to fix it. There are two holes on the ring, and on the key there are two pins corresponding to the dimensions.
  • The key must be put on top, into the holes of the ring, and turned counterclockwise. If the disc has not been changed for a long time, the ring may stick to it (not moving from the operator’s efforts). In this case, the key will have to be lengthened with any tube and try to unwind the ring again.
  • After removing the old abrasive, you need to put a new one in the nest. Put a metal ring on top and tighten it clockwise with a wrench. It is advisable to press the key again to check if the abrasive is fixed.

Important! Do not apply great effort when tightening, otherwise there is a risk of damage to the disc disc.

The main difference between the two sides of a circle

On any angle grinder disc, you can easily notice differences on the two sides of the wheel. One side is plain, it is covered with abrasive materials (for working with different types of metals). The front side has a special label on which they write information about the characteristics of the cutter.

But the main difference between the two sides of the circle is the presence of a metal ring. This is an important design element that affects the safety of use, and therefore deserves a separate mention.

Which side to install the disc on the angle grinder

Placing the disc on an angle grinder is easy if you follow some fairly simple instructions. This information is extremely important to the wizards, as it is the disc that determines the functionality of the instrument. With the disc, you can use the angle grinder (angle grinder) to grind, cut or polish various kinds of materials. How to properly place the disc on an angle grinder, further in the article.

Which side to put the disc on the angle grinder

In most cases, the abrasive for an angle grinder is installed in only one direction, but in a situation when working with stone or concrete, the process changes. Therefore, you need to consider these cases separately.

Place the disc differently depending on the situation.

Ease of installation

Another advantage of face-out disc installation is that the user will always see which attachment is mounted on the angle grinder. To work with stone or metal, you need to use different discs, and if you make a mistake, you can get serious injuries due to a rupture of the cutting part.

For example, if you use a metal disc for cutting concrete, then the abrasive simply will not withstand the load and will fly apart in pieces in different directions. Therefore, the considered installation option provides not only convenience, but also safety.

Advantages of ring-mounted disc to angle grinder

There is no exact direction to follow when setting the wheel to the sander. But, as already described above, if you put the cutter “face” out, then the removal process will be simplified, since it is more difficult to catch on the surface from the abrasive side.

Apart from this, there are a few more benefits that will be useful to know about.

Guaranteed even installation on the shaft

A metal ring on the disc increases the bearing area so that the tightening pressure becomes even. Thus, the disc will sit as smoothly as possible on the desired surface. The possibility of skewing will be excluded. This directly affects not only the evenness of the cut, but also the safety of the user. the abrasive will not fly into pieces if it does not cling to the angle grinder.