Proper installation of the disk on the angle grinder

Today, after another dispute. which side to put a disk on the “angle grinder”. I decided to express myself on this subject in writing, after all in my opinion this question is quite interesting.And by the way in the future rather than rekindle demagogy, it is better to just throw a link to this record.I work in the shop (mainly power tools) and I see that quite often worn angle grinder with a “jammed” discs. Sometimes it jams so much that you have to dismantle the gearbox and clamp the pinion in a vise to unscrew the nut with a big gas wrench.Interestingly, the nuts are stuck only on machines with the disk installed on the right, that is, a “spark” from the machine. If we consider that under a normal load torque on a small spindle then occur such a bad self-tightening of well it should not happen, but it happens, why??. Because of the shock loads that with the installation of the disc on the right generally common phenomenon.Why this happens is easier to explain on the example (too lazy to draw). start the bike, and, holding it by the steering wheel trying to arrange a slipping of the leading (rear) wheel.

here is the fullest analogy with cutting with a surface grinder with a disk “from yourself” will be if we hold the wheel standing in front of the motorcycle. Try it, you’ll love it. If you like to cut “from yourself” you will like it for sure.There’s an important note: the higher the support and the shorter the base, the more interesting the effect.And another thing, the center of mass of the grinder and the hands that hold it is above the plane of cutting (or rather the vector of force), it leads to a strong jerk, and as a result, often to the breakdowns and injuriesIn short, it turns out that the work of the angle grinder “from itself” is something like a dangerous ride with slipping on the verge of “getting up on the goat.

Now, how it will be if the disk stands on the left and “sparks” under the bumpers: We take the FRONT DRIVE motorcycle, naturally start it, we switch on gear and, holding the trunk, admire how wonderfully the front wheel sticks. Exactly BOOKS (in an analogy cuts) and not “drives” under the fulcrum, increasing clutch and trying to raise the steering wheel, as it is with the rear-wheel drive.So it turns out that, as a system, the “front-wheel version” is more stable and predictable, even if we push the wheel from above.Well, it’s like this Maybe idiotic, but figurative.

I was cutting a couple of months ago, sticking out under the ceiling rail, cut one standing on a stool a huge angle grinder at 2.2 kW, in addition, with the protective cover removed (with it, well, well, no way!).If I’d been cutting away from myself, I’d have been killed and more than once.

A new version of this article was published by me at

I have used an angle grinder in a cottage industry for several years, and all this time I have no answer to two questions: which side to put a cutting wheel, and in what direction it should rotate. “I searched all over the Internet, but did not find a definite answer to these questions. Opinions are equally divided. Both sides make convincing arguments, while any authoritative official documents are silent on the subject. Manufacturers are also silent. Today I want to reflect a little on this subject in order to determine, to begin with, the first question.

So, which side should I put the cutting-off wheel on my angle grinder??

Install angle grinder disc | Angle grinder safety

Bottom line. In the center of the wheel (cutting or grinding) is a ring of galvanized steel, which has four punched holes around the circumference, usually with indented edges, to prevent rotation of the ring relative to the abrasive. The inner edge of the ring wraps inside the wheel, into its center hole, and ends flush with the opposite face of the wheel, without going over it.

As manufacturers say, this ring is made to protect the shaft that rotates the grinding wheel. “Highly likely”, this is its main function, otherwise the abrasive will eventually rub through the groove on the angle grinder shaft when you spin the disc, and it will be impossible to center it. Note that in the manufacture of wheels, the ring is riveted on top of the disk during compression, after the entire pie of mesh and abrasive is formed. So, it does not have any technological function, as it was mentioned somewhere in the Комментарии и мнения владельцев of an “authoritative” source. I’ve watched a number of different commercials on lap production, and everywhere the process was about the same. the ring was pressed into the disc from above while the formed disc was being compressed by the press.

The ring is usually on the label side of the wheel. However, there are circles where the ring comes out on both sides of the circle, and on some circles with a recessed center, it is only on the side opposite the label and is on the recessed side. That is, manufacturers mold the rings in different ways. Although, admittedly, most cup wheels still have rings on the convex side, which “sort of hints” that it is still preferable to put the discs with the ring down.

In the beginning, after I bought an angle grinder, I intuitively put a circle with a label outward. On that circle, the metal ring in the center was also pressed on the picture side. That’s how I was sawing, and I had no problem with it. But then I got a cup shaped circle (with a recessed center) and it had the picture and the ring on the convex side. I put it with the picture facing out, and it turned out that the circle was scraping against the guard. I had to turn the circle. That’s when I had this question for the first time.

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

These points tell us that “with a high degree of probability” it is possible to put saw blades with any side.

install, disk, correctly, angle, grinder

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

On the left is the washer that is put on the shaft. It has a ribbed surface and a rubber ring at the inner edge. The nut on the right, though not polished, has a fairly smooth surface, which in the photo lies upwards. The washer must be clamped between them. At first I thought that the ribbed surface of the washer was as if designed to grip the abrasive, and the smooth nut should slide well over the ring so that you can easily tighten it. But it was a little disconcerting to see the rubber ring, which was clearly made to cling to a smooth surface, and would surely deteriorate if the sharp, burr-ridden edge of the hole on the abrasive side often had to be pressed against it.

What can be done with an angle grinder

angle grinders have different characteristics, drive types and costs. But regardless of the service life, quality and reliability of a particular model, these power tools have the same area of application. It can be used for grinding, cutting, scraping tiles, wood, metal, stone, brick and concrete. Angle grinders are used both at home and in the workplace. And for professional builders and repair specialists, it is as familiar a tool as a hammer or drill.

the angle grinder must be used properly and prepared carefully for work. The best choice for the task in hand is the appropriate attachment. To do it properly there are three simple rules:

  • The larger the disc diameter, the more powerful the tool must be. Smaller discs are best for high RPM. You need different discs for different materials. Metal is cut with an abrasive disc, concrete with a diamond disc.
  • Familiarize yourself with the marking and characteristics of the disc (diameter, type, etc.).e) That way you can see whether or not it is suitable for your application.

The following blades are made for lathes:

  • Cut-off wheels. for cutting metal and pipes,
  • Saw heads. for cutting wood,
  • Roughing. for grinding work,
  • Stripping. for cleaning rust from workpieces.

How to install an attachment on an angle grinder? Here are step by step instructions:

  • Unplug the tool from the mains.
  • Lock the shaft by pressing the lock button.
  • Unscrew lock nut with double-headed wrench.
  • Replace the old bit with a new one.
  • Use the two lug wrench to secure the lock nut.

Operating instructions and safety precautions for use with the angle grinder:

  • Wear protective gear: eyeglasses, overalls, closed tops shoes.
  • Prepare the work area carefully. keep it tidy and remove any surplus material.
  • Keep flammable materials out of work area.
  • Keep tools away from you. If the blade breaks, the shards will fly past and at a safe distance.
  • Make sure the angle grinder disc is covered with its guard.
  • Do not put pressure on the disc while working. An angle grinder can do the job unaided. All you need to do is hold the tool and point it in the right direction.
  • Don’t turn on the angle grinder if the disc is stuck in the kerf.
  • Cut metal profiles where there is minimal cross sectional area.
  • Cutting ceramic tile, brick, or concrete is dust intensive. So wear a respirator beforehand. Be careful when cutting concrete and walls: electrical cables, pipes or fittings may be hidden inside. They can stop the disc.
  • Store your angle grinder with the disc upward.

What you need to fit the disc?

Installing the disc on an angle grinder is usually a fairly straightforward process in which you need to follow a few rules. In order to make it, it is necessary to arm yourself with the appropriate tool. a wrench, which will be needed to unscrew the nut. The next step after unscrewing it, will be the replacement of the disc angle grinder or its primary installation. If it happened that the disc is jammed in the angle grinder, to remove it will have to crush it and remove the remains from the gap between the supporting flange and the nut with a flat screwdriver or chisel.

What side to put a cutting disc may depend on several factors. Firstly, if the disk is not flat, you can put it only one way and the question disappears by itself. Secondly, if the disk is flat you can be guided by the label. if the angle grinder turns away from yourself it is placed with the label inside, if towards yourself it is placed outside. If this principle is not followed, you can expect unwanted results. disk breakage in the process of sawing or just its rapid wear.

As for the direction in which the disk rotates on the angle grinder, it is primarily a question of safety. It is believed that the concrete should be cut in the direction of rotation of the disk or on itself. Ideally, the sparks should fly to the side to the left of the person working with the tool. If this cannot be done, then another position can be used where the shear of sparks is directed downwards. In any case, you can not allow a situation where sparks fly away from the user, as in the case of a sharp jamming of the disc, the angle grinder will be directed in its direction.

In other words, it is extremely unsafe to cut materials against the direction of disc rotation or away from yourself, because in the case of a wedge, there is a sharp ejection of the angle grinder in the direction of the person working. By the way, if you have additional questions about how to install the disk on the angle grinder, you can also view training videos, which today on the Internet more than enough.

If you still have questions or need advice on changing and installing the discs, just leave an application online or call the listed contact number and our experts will tell you how to act correctly. For our complete range of diamond discs please see the diamond discs section.

Size and types of cutting discs

The main types of abrasive supplies for the angle grinder (angle grinder) are 41 type. flat and 42 type. with a concave center. Usually type 41 is used for work, and type 42 is used in hard-to-reach places, where the first option is not suitable because of protruding elements in the grinding wheel mounting area.

The main diameters of grinding wheels range from 115 to 350 mm with bores of 22, 23, 24,5 or 32 mm, depending on the tool used.

It is not safe to install a cutting wheel with a larger diameter than it should be on the angle grinder.

The thickness of the cutting wheel affects the choice, because the use of the consumable for a particular application depends on this parameter. The standard thickness for cutting wheels is 0.8. 4 mm, for grinding wheels 6. 32 mm.

How to choose an angle grinder and tool

In order to use cutting wheels efficiently, you need to follow the recommendations and material and speed requirements of the discs.

For example, it is best not to use a metal cutting disc when cutting stainless steel because metal cutting discs are made of aluminum oxide grain, which causes the contact area to become black when cutting stainless steel. In turn, stainless steel cutting wheels are made from silicon oxide grit. Using a disc at a higher speed than labeled can cause it to break.

Remember that thinner consumables provide faster cutting speeds, produce fewer chips, but also wear out faster. Do some research at work to decide on the effectiveness and quality of the lap.

Operating rules:

  • Provide the necessary pressure on the wheel, it should not be too much and not too little. Do not apply too much pressure to the wheel, otherwise there is a risk of losing control of the tool. Cutting wheel can slip, causing damage to the disc and injury to the operator.
  • The thinner the cutting wheel, the more susceptible it is to side loads. If there is high pressure on the cutting disc, it will deform and get stuck in the cut.
  • Store cutting wheels in a clean and dry place. The Bakelite bond of cutting wheels loses its properties in high humidity, which lowers their strength and service life.
  • Inspect the cutting wheel for damage before use. If there are cracks, deformation and other defects, it is better not to use such a disc.

Do not use expired cutting wheels because it will affect performance. Always follow proper storage rules for consumables. Wear PPE when working with an angle grinder. Never remove the safety guard from the angle grinder.

Useful information. deciphering the composition of the wheel

By marking on a cutting disc from the manufacturer you can establish such indicators as brand, grit of abrasive material, the type of bond. vulcanite, ceramic or Bakelite, the hardness and structure of the circle, the presence of reinforcing element, accuracy class and operating speed. Let’s look at what the inscriptions on a metal grinding wheel mean, for example.

The format of this inscription would be “A 60 T BF”

  • “A” (in our case) indicates that the abrasive of the metal wheel is normal electrocorundum.
  • WA stands for white electrocorundum.
  • C. silicon carbide black.
  • CS means green silicon carbide.
  • Z/AZ stands for zirconium.

The next number tells about the size of the disc grain. The smaller the number, the higher the grit. Let’s say that 60 on a cutting wheel is a low grit, but 24 is a high grit.

The letter “T” on the wheel will tell you the hardness of the element. The further the letter is in the alphabet, the harder the wheel is:

  • F-J. soft;
  • K-L: medium-hard; K-L: medium-soft;
  • M-N. medium;
  • O-Q is medium-hard;
  • R-S are hard;
  • T-Z. very hard discs.

The last symbols in our marking indicate the type of bond materials in the cutting disc:

The key to productive work on the angle grinder will be a competent choice of cutting wheel and compliance with safety rules. The construction season is coming, so the use of angle grinders will increase. We hope our tips will help you find the right tooling for your tool.

Typical disc sizes

When selecting a disc for your angle grinder, make sure that the outside diameter of the bit does not exceed the maximum allowed for your angle grinder. For example, if your angle grinder is designed to use a wheel with a maximum diameter of 125 mm, you can not install a 230 mm wheel on it. And there are several explanations for this:

  • will be exceeded the linear velocity of the cutting edge, which is fraught with the destruction of the abrasive disk and causing injury to the user;
  • a small angle grinder does not have enough power to work with a large tool;
  • installation of the tool, exceeding the allowable dimensions, requires removal of the protective cover, and it is already a violation of safety rules.

Discs for angle grinder have standard sizes: 115, 125, 150, 180 and 230 mm. In modern angle grinders, the seating diameter (diameter of the shaft on which the tool is installed) is practically the same and equals 22.2 mm. If you “stash” an angle grinder of an obsolete model, you will need to use adapters. rings of different diameters.

All abrasive wheels of all sizes are marked with a special symbol, from which you can find out the following information: disk diameter and thickness, seating diameter, maximum rotation speed, and the materials for which it is intended.

Carefully remove the cutting wheel

Before you start to remove a worn cutting (or any other) wheel, you need to buy a new one. Choosing a new disc is not a difficult task. It depends on the nature of the work to be performed.

According to the functional purpose of the nozzles are divided into:

  • Cutting (there are abrasive and diamond, created for cutting products from various materials);
  • Stripping (used to remove paint and rust);
  • Stripping (used for sanding various surfaces);
  • sharpening (all possible tools are sharpened with them);
  • Sanding and polishing, used for finishing.

Diamond cutting discs have a dusting of different composition and hardness, so there are nozzles for metal, brick, wood, slate, concrete, ceramics. They are much more expensive than others. The most popular cutting discs for metal. Steel discs are noticeably different from other discs. Although they can be used to cut other metals, it does reduce the life of the tool bit considerably.

Scrubbing nozzles are metal circles with pressed steel brushes. Metal parts of the brushes chafe over time, so we had to wear protective gear for this kind of work.

Stripping nozzle consists of a base, to which is glued sandpaper with large grit: from 0 to 00 for coarse stripping and from 20 to 80 for fine. Such blades should not be used until the emery has worn down completely. Otherwise it will be torn.

Sharpening discs are used for rough sharpening of tools. They are much thicker than the cutoff ones. If you use an angle grinder for this purpose it must be rigidly secured to prevent injury.

Grinding and polishing wheels are used on machines with adjustable speed. They can also be used on special grinders.

Such an abundance of different nozzles may confuse the inexperienced user, but it is a treasure trove for any professional.

The outer diameter of the rod, to which with a flange and nut is attached nozzle, in all grinders is the same and is 22.2 mm. The disk size depends on the design features of the tool and is selected from the range of diameters recommended by the manufacturer.

Discs have a factory marking, on which among other parameters (abrasiveness of working surface, grit size, hardness, accuracy and unbalance classes) the size and maximum rotation speed is indicated. It must exceed the same parameter of the angle grinder. Most of the above characteristics are clear without comment, except for the unbalance class. This parameter characterizes the unevenness of mass distribution of the material of which it is made by volume. It affects the amplitude of the “beating” of the bit.

Disconnect the tool from the 220V power supply before starting work on replacing the nozzle. To remove the wheel, you need to include a lock on the machine body, which does not allow the flange of the product to rotate. Using a special or open-jaw wrench you can try to unscrew the nut. If unscrewing still fails, it is better to put the tool on a flat surface so that the drive was parallel to it and drop a small amount of WD-40 on the thread on the rod of the nut side. After that you should wait for about 10-15 minutes. The nut should unscrew easily. The special wrench tends to get lost. Therefore, it is a good idea to attach it to the body of the angle grinder on a flexible strap long enough so that it does not restrict the freedom of movement of the worker.

The main difference between the two sides of the wheel

Two surfaces are clearly distinguishable on any cutting disc. One of them (back) is monochromatic and is formed by the abrasive material. The second (front) has a label with basic information about the blade characteristics. But the main distinguishing feature of the two surfaces, is the presence of a metal ring on the front side.

The metal washer (ring) is designed to protect the integrity of the disc when it is tightened by the moving flange nut, as well as to increase the support surface area. Metal washers also prevent the cutting wheel from “sticking” to the nut surface, making disc replacement much easier.

Which side is better to put

According to experienced craftsmen, it is recommended to install the outward side with the image and crimp ring. This variant has a number of significant advantages.

  • easy and simple disk replacement. the outer arrangement of the cutting ring ensures easy dismantling of the cutting element and the nut. If the nut is on the side with the abrasive surface, the nut will be much harder to unscrew;
  • even positioning of the cutting wheel. the presence of a crimping ring helps to increase the support area of the nut when installing the wheel. The load on the cutting element is distributed evenly, ensuring long service life. The disc rests evenly over the entire surface of the support nut;
  • Convenience of the availability of information about the parameters of the element. the presence of the image on the characteristics of the disk on the outside gives the master an opportunity to be fully confident in the correctness of the application of a circle. This is connected with the fact that the ability to use a disk for work with different materials (concrete, metal, stainless steel) depends on the disk parameters. Diameter, also located on its outer side, indicates the allowable speed of its rotation. The presence of the manufacturer’s trademark, indicating its quality and reliability.

There are some important features to consider when selecting a cutting element. For example:

  • What kind of materials are you intend to work with? This determines the grit size of the abrasive surface of the consumable.
  • Power model of the angle grinder. When working with a powerful tool, it is recommended to opt for a durable disc, made by a well-known brand.
  • Tooling diameter. Its dimensions must not exceed the angle grinder’s housing. The most common diameters are 125 or 230 mm. They can fit most domestic and foreign models.
  • the thickness of the circle. This criterion ranges from 1, 0 to 3, 0 mm. It is worth bearing in mind that the smaller the thickness, the more fragile the disk is. Dependence of disc diameter and thickness is established. An increase in one parameter results in an increase in the other.

It is recommended to mount the disk on a pin with the side on which there is an image and its criteria. This ensures the correct fit and duration of work with it.

| Denial of responsibility | Contacts |RSS