Most repair specialists and construction work Today we are well familiar with an angle grinder or, as it is popularly called, an angle grinder. It is used to process a variety of materials, including stone, reinforced concrete, concrete, marble and many others. At first, beginners may have a number of questions, among which the most common are: how to properly install the disk on the grinder, how to secure the disk on the grinder, which side to put the disk on the grinder, and in which direction the disk on the grinder should spin. Let us now try to briefly answer all these questions.
What is required to install the disk?
Installing a disc on an angle grinder is usually quite simple process, in which several rules must be followed. In order to do this, you need to equip yourself with the appropriate tool - a wrench, which will be necessary to unscrew the nut. The next step after unwinding it will be replacing the grinder disk or its initial installation. If something happens that jams the disk in the grinder, to remove it you will have to crumble it and remove the remains from the gap between the support flange and the nut using a flat screwdriver or chisel.
Which side should you put the disc on the grinder?
Which side to place the cutting disc on may depend on several factors. Firstly, if the disk is not flat, then there is only one way to place it and the question disappears by itself. Secondly, if the circle is still flat, you can focus on the label - if the angle grinder rotates away from itself, then it is installed with the label inward, if towards itself, then, accordingly, outward. If this principle is not followed, then you can expect undesirable results - the disc breaking during the sawing process or simply wearing it out quickly.
As for which direction the disc on the angle grinder rotates, this is primarily a safety issue. It is believed that it is necessary to cut concrete in the direction of rotation of the disk or towards itself. In an ideal position, sparks should fly to the side to the left of the person working with the tool. If this cannot be done, then you can use another position when the sheaf of sparks is directed downwards. In any case, a situation should not be allowed where sparks fly from the user, since in the event of a sudden jamming of the disk, the angle grinder will be directed towards him.
In other words, cutting materials against the direction of rotation of the disk or away from oneself is extremely unsafe, since 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 additional questions arise regarding how to install a disk on an angle grinder, you can also watch training videos, of which there are more than enough on the Internet today.
If you have any questions or need advice on changing and installing disks, just leave a request on the website or call the specified contact phone number, and our specialists will tell you how to proceed correctly. The entire range of our diamond blade products is presented in the diamond blades section.
Comments:
Having figured out how to work an angle grinder correctly, you will ensure high-quality execution existing tasks and protect yourself from possible injuries.
Before starting work, be sure to familiarize yourself with the safety precautions for working with an angle grinder.
It is important not only to be able to cut correctly with a grinder, but also to comply with safety requirements.
Preparing to work with an angle grinder
Recommendations on how to properly work with an angle grinder would not be complete without a description preparatory stage. First of all, you need to prepare and get ready for work. If safety precautions are not followed, the grinder becomes a very dangerous tool. Therefore, it is better not to pick it up if you are sick, too tired, and especially drunk. Fatigue and lack of composure lead to negligence, which in the case of an angle grinder can cost health and even life.
To work with an angle grinder, safety glasses are a must.
You need to prepare protective equipment. Safety glasses and a cover must be present. Without them, cutting with a grinder and performing other manipulations is prohibited. Splinters, sparks, scale, etc. - all this inevitably appears when working with an angle grinder. If these particles get into your eyes, they can cause serious injury.
The mask or glasses must be closed. The flight path of fragments and sparks is non-uniform. If the mask or glasses are open, sparks may fly through them. It is better that the mask has a safety net, because... an unreinforced product may break at some point.
The safety guard is a barrier between the grinder wheel and the operator. During operation, the circles break quite often. Almost everyone who periodically uses an angle grinder has had to deal with this. In most cases, the cause of the destruction of the circle is its jamming in the slot. Installation of the protective casing is carried out so that no fragments or sparks fly towards the operator. If the circle breaks during operation, the casing will protect the person working with the angle grinder. The opening in the casing sets the sector for the scattering of fragments and protects the operator from injury.
The casing must be secured so that there is no possibility of it turning spontaneously. Sometimes work with installed casing very inconvenient, but it must not be removed under any circumstances, otherwise the consequences for the operator’s health may be most unfavorable.
In addition to glasses, you must also have other protective equipment, in particular gloves or mittens. When working with an angle grinder, the operator keeps his hands very close to the rotating circle; it is important to protect them from metal fragments, sparks and other particles that are formed. The best option is thick protective leather gloves. Cotton products do not guarantee reliable protection of hands from sparks.
When cutting stone materials, You need to wear a dust mask.
When processing stone materials in conditions where there are no devices for dust extraction, the operator must wear a dust respirator. You need to work in well-tucked, loose clothing. It is important to remove all loose parts so that they do not get caught in the rotating circle during operation.
The working circles for the grinder deserve special attention. Each type of material is processed using a wheel specially designed for it. You cannot use wheels that are not designed to process the existing material.
Do not install wheels on the tool. larger size than indicated in the instructions. Grinders of small sizes operate at a higher rotation speed than tools of large sizes. During operation, large circles may not withstand high speeds and collapse. When rotating a large circle, the bearings will experience increased load, which will lead to faster wear and generally reduce the service life of the angle grinder. In addition, to install a circle of an unacceptably large size, you will have to remove the casing, which is also prohibited.
When working with an angle grinder, you should use only intact discs without visible damage.
Do not install damaged or deformed wheels. This may cause a kickback and lead to the destruction of the circle. Possible injury to the operator.
After the tool is installed, the angle grinder will need to be checked for at least 1 minute at maximum speed. The circle should rotate freely and the vibration should not be stronger than usual.
Thus, in addition to the grinder itself, you will need:
- safety glasses or mask;
- dust respirator;
- special protective clothing;
- thick leather gloves;
- construction vacuum cleaner;
- suitable nozzles.
Having mastered all the features of preparation, you can begin to understand how to work with an angle grinder correctly.
Features of working with an angle grinder
During operation, the grinder must be held firmly with both hands.
If the own weight of the workpiece is not enough for it to remain motionless during work, it must be secured with clamps on a heavy structure. You can also use a vice for this.
Working with an angle grinder requires performing a number of general requirements. First of all, the sander must be held firmly with 2 hands - this is one of the basic requirements that must be strictly fulfilled under any circumstances. If the operator holds the grinder securely in his hands, then even a reverse blow will not cause the tool to be pulled out or be greatly displaced.
You need to work on a flat and stable surface, there should be no chance of imbalance. The power cord of the grinder must be located on the side of the rotating disk so that the circle does not catch it and cut it, because. this can lead to a sudden stop of the circle with the angle grinder shifting and a short circuit.
The tool must not be released from your hands until the rotating disk has completely stopped. Otherwise, the circle may catch on any foreign surfaces or objects.
When working with an angle grinder, everyone except the operator should be kept at a distance, as sparks fly from the angle grinder.
If you need to move from one place to another, you must turn off the grinder, because When moving, the rotating disk can touch foreign objects, catch clothing, etc.
If the power suddenly goes out during work, the tool must be turned off so that when the power supply is restored it does not start uncontrolled.
Grinding and cutting wheels become noticeably hot during operation. It is important not to touch them until they are completely cool. Everyone except the operator must be at a sufficient distance from the workplace so that abrasive particles, sparks, wheel fragments, etc. they were not harmed.
The spindle must reach full speed before cutting material. Otherwise the circle may jam. Manufacturers of such tools recommend cutting so that the tool and wheel move in the same direction. This eliminates the possibility of the cutting disc coming out of the slot uncontrolled.
During the cutting process, it is necessary to hold the working tool correctly. It is necessary to ensure that the cutting line passes the operator. She can't let her push against him. This reduces the risk of injury if the wheel gets caught and breaks. There must be a protective guard between the operator and the cutting blade.
When cutting with a grinder, under no circumstances should you put too much pressure on it.
It is important not to apply excessive force to the tool while working. He must do most of the work “on his own.” If overloaded, the circle may warp and jam. The operator must control the movement of the tool, pressing slightly on it where there is such a need. When processing profiles, you need to cut from the smallest cross section. It is forbidden to turn off the grinder if the disc is located in the cut.
Cutting concrete and ceramic products must be carried out using wheels specially designed for this purpose. During the processing of such materials, a lot of dust harmful to health appears. Therefore, a dust removal tool must be present at the workplace. If this is not available, the operator must work in a dust respirator.
Rules for grinding with an angle grinder
Grinding should be carried out using cutting wheels of sufficient thickness - discs that are too thin should not be used.
Do not grind with the side surface of the disc that is not intended for grinding. Under the influence of significant lateral forces, the circles may break. You need to grind with the edge of the disc. The angle of inclination to the grinding plane should be 15-40°.
The operator should move forward and backward while applying moderate pressure. When starting to work with a new circle, you cannot move forward, because... the disc may cut into the workpiece. It is important to wait until the edge of the circle is rounded. After this, they can be moved both forward and backward.
What is a kickback?
One of the most dangerous factors when working with an angle grinder is the kickback. This is a sudden and very sharp kickback of the grinder, which occurs when the working disk jams in the material. In most cases it is accompanied by disc destruction.
You can prevent a kickback or at least minimize its consequences by observing a few simple requirements safety precautions:
Layout of the most dangerous sectors when working with an angle grinder.
- The grinder must be held securely, always with two hands. The tool is held by the existing handles.
- You need to stand on a hard surface. This will allow the operator to withstand the force of the kickback.
- During the kickback, the tool will move in a certain direction. It is important that the operator stands away from the suspected site of injury. If the operator moves the tool away from himself, then during a reverse strike the angle grinder will most likely bounce right back at him.
- You must be especially careful when processing sharp edges and all kinds of corners. You should be prepared in advance for possible tool rejection. Kickback often occurs at the very end of the cut, when the last bridge connecting the parts of the material being processed is cut. In such situations, you should, without finishing the cut, remove the disk and carefully cut the last jumper on the other side.
- If the grinder is jammed, it must be turned off and removed from the cut.
Special safety requirements
When working with an angle grinder, you must observe a number of important requirements safety precautions. Although they do not directly relate to the grinding and cutting operations themselves, they must be taken into account.
First of all, flammable materials must be removed from the work area. Flammable gases and liquids must not be allowed to be present in the immediate vicinity of the workplace.
From the workplace you need to remove everything that could be damaged by splashes, sparks, splinters, etc. In particular, you should not work near windows. If this is not possible, windows and other valuable objects must be covered with some kind of suitable material. A thick, wet cloth will suffice.
When working in conditions high humidity air, the grinder must be connected to the network through a residual current device to avoid electric shock. Do not trust work with an angle grinder to persons whose qualifications you are not sure of. It is important that there are no children near the operator while working.
By observing these simple rules and recommendations, you can quickly solve all problems that require the use of an angle grinder, without involving third party specialists. This will allow you to save money and be confident in the quality and integrity of the work. Do not neglect safety requirements and you will succeed!
- Method 1. Gas wrench with good jaws, the flange nut on the angle grinder is quite narrow, and a fairly good grip is required. Often it is possible to unscrew the nut in this way, but you should not use much effort; you can break the locking button (if it is still intact!), its design is designed to apply the force possible when using only a stationary wrench.
- Method 2. If the locking button on the angle grinder is already broken then you will have to remove the gearbox cover; there are three or four bolts under the disk. The disc usually breaks off down to the nuts. The cover is unscrewed, the gear is removed from the gearbox and clamped between aluminum jaws into the planks and the nut is unscrewed using the methods indicated here.
- Method 3. The drill is clamped into the hammer drill, only the chiselling mode is set (without rotation), and force is applied to unscrew the nut (into the edge of the nut or into the hole for the key pin).
- Method 4. The nut is heated with a hot air gun (gas burner, blowtorch) and unscrews much easier, using the same stationary key or a gas key.
- Method 5. If the disk is broken, you need to remove its remains with pliers up to the very radius of the nuts (or break the whole disk if you don’t mind). Clamp a sheet of iron in a yew with a thickness equal to the thickness of the disk or slightly less. Turn on the grinder and literally grind the disc against the edge of the iron clamped in the yew. When the remains of the abrasive disk between the washers are ground down with a diameter less than the diameter of the clamped planes, the nut will also unscrew by hand.
- Method 6. This method is the same as 5 only instead of a piece of metal, in The yew is clamped with the same abrasive disc The process is faster, but you have to be careful not to spoil the geometry of the nuts on the fixed disk clamped in a yew. Otherwise, you will have to trim the planes later.
- I advise you to use almost no force on the stationary wrench when tightening the disk nut. during rotation, the nut tightens itself, as much as necessary to hold the disk.
- After the nut is unscrewed, you can weld a regular nut onto the flange with carob edges spanner(which one to choose depends on the diameter of the shaft thread)
- Do not neglect installing cardboard spacers under the grinder nut, this reduces jamming.
- After the cardboard spacers supplied with the angle grinder run out, you can cut out gaskets from thin nylon (old plastic canisters) In case of jamming, you can simply melt it with a regular torch or blowtorch and the nut will unscrew by hand.
- And finally, one more basic piece of advice, I thought I knew it all, but as it turns out, I don’t. All discs have paper pasted on one side with the characteristics of the abrasive fraction and purpose. On the same side (paper side) the inner disk washer has wide ring. So here it is Place the abrasive disc with this paper side facing the gearbox. A wide washer on this side prevents biting, and when unscrewed by the disk, it will slide along the fixed (inner flange) making it easier to unscrew the nut. As the manufacturer does it (photo) -
In this case, you can try to unscrew the nut using a gas wrench as an assistant. You can also resort to heating and further unscrewing. But look, in the first case, you need to do everything carefully with the gas wrench, not too much, since such efforts can contribute to the breakage of the latch. And in the second case, the heating should also not be too strong so that it cannot affect the plastic parts.
Well, yes, so much suffering because of some jammed nut. A beard and a hammer are always at hand. He inserted it into the key hole and gave it a sharp squeeze. Since ancient times, the technique has worked and does not fail. Well, if your hands grow from there, then you can cope with any pieces of hardware at hand.
You heat this nut with a torch, and unscrew it, everything is simple and easy and you don’t spoil anything.
A jammed nut on an angle grinder (angle grinder) This is a fairly common problem that everyone solves in their own way, but the fact that this annoying (albeit natural!) misunderstanding takes a lot of time and effort is for sure.
First, determine the direction of rotation of the disk, because the nut will need to be unscrewed exactly in the same direction. If we looked on the Internet, it means that using a stationary wrench, we couldn’t unscrew the nut; it was either broken or bent.
There are some ways to unscrew a jammed nut on an angle grinder.
Well, now let’s try to protect ourselves in the future from unnecessary movements to unscrew the jammed nut and possible damage to the tool.
You can try to unscrew the nut in several ways. As a rule, there is a spline on the gearbox shaft for a simple key - do not neglect it, otherwise it is easy to break the stopper. Holding it by the shaft (the wrench should be a little thinner than the standard one), try to unscrew the nut with a gas wrench. It won’t work - don’t despair, you can try to warm up the nut, but you should take into account that there are plastic parts nearby - warming up requires care.
The most effective and most available method- this is a sharp blow on the nut in the direction of unscrewing. Holding it by the shaft, insert a thread (for example, a dull chisel) into the key hole and with a sharp blow, tear the nut out of place. Then it's easier.
For the future, place the disc on cardboard spacers, then the wedge will become a rare guest.
An angle grinder (popularly called “grinder”) is the most common tool for home craftsmen after an electric drill.
Despite the ease of use, “hobbyists” often have questions about servicing the tool, especially when emergency situations arise. As a rule, breakdowns occur due to improper use of the tool.
Main uses of angle grinders
It is with such attachments that emergency situations most often occur.
Let’s take a closer look at cutting wheels
The question of which side to place 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 (from yourself or towards you) is determined by the position of the protective casing. The choice depends on the position of the tool that is convenient for the operator. 
In addition, the direction of the flow of sparks (or stone dust) depends on the position of the casing.
Please note
It is advisable to place the disc with the front side (with the marking) facing 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, the kit includes a dismountable flange. Bottom part it is rigidly fixed with chamfers, the upper part is a regular self-tightening nut. It is she who determines in which direction the disc on the grinder should rotate. During operation, the threaded connection is tightened, preventing the nozzle from coming off. 
Sometimes the kit includes spacer washers designed to dampen transverse vibrations. You can make them yourself from thick electrical cardboard or paronite. 
To secure the flange, a special open-end wrench is included with the tool. The shaft is fixed with a clamping button to create the necessary tightening force.
This summer I was planning thorough work with the grinder, deciding which abrasive wheels to purchase additionally and looking for information on the Internet. In the process, I accidentally stumbled upon creepy facts not for the faint of heart...
Even a quick glance at any thematic resource made it clear that such situations occur regularly and are the rule, not the exception. Both young, inexperienced guys and mature men work carelessly and get injured.
On mastercity.ru there is a thread “death from an angle grinder” in which sad content regularly appears...
Generalized information on the topic of how to work correctly and safely with an angle grinder, as well as conclusions from personal practice, are presented in this material. Let's go in order.
1. Introductory part. Young fighter course
A grinder, also known as an angle grinder (angle grinder). Brief information for those who hold this capricious instrument in their hands for the first time.
1.1. Grinder device (angle grinder)
On/off button
Spindle lock button (spindle rotation is blocked when the tool is turned off when replacing abrasive discs)
Lever. Rubberized as in the photo. An angle grinder produces noticeable vibrations during operation.
Protective cover. Removing it is strictly prohibited!
Air channels. Try not to overlap them with your palms so as not to overheat the angle grinder.
Abrasive disc. In this case, grinding.
Do you know why the Bulgarian is called the Bulgarian?
The proper name “Bulgarian” appeared in the 70s of the last century, when the first representatives of this type of instruments, produced in Bulgaria, arrived in the USSR. They were called "Fortune".
The Bulgarian plant "Elprom-Lovech", now Sparky, was the first in the CMEA to begin production of this type of power tool, purchasing an AEG license in 1966.
1.2. Actions with an angle grinder. What can you twist and change?
Some models provide the design ability to change
1.2.1. Handle position
1.2.2. Guard position
But never remove it completely!
Very conveniently made by the Japanese (Kawasaki). In a couple of seconds you can rearrange without a key.
The click system also looks interesting, but I personally have not had to use it.
Attention!
If you found it in a garage, received it at a factory, borrowed it from a neighbor, or somewhere else you came across a used angle grinder without a protective cover, then refuse the job or arrange for it to be available. Never work without a protective cover!
1.2.3. Speed adjustment
There are excellent angle grinders on sale with a speed controller. I use it myself and highly recommend it. Economic considerations are also useful here - the consumption of abrasive wheels will be 2-3 times lower.
If your grinder does not know how to regulate the speed itself, then look for an adjustable autotransformer (LATR), many people use homemade ones. With this device you can overcome the frantic speed of the grinder and even turn it into a polishing machine.
1.2.4. Replacing the drive
We change the disk as follows:
We de-energize the tool (you can simply unplug it from the socket)
Press the spindle stopper (see the grinder device above)
Use a special wrench to unscrew the lock nut.
This not the most convenient option will be on your grinder by default. When you get tired of turning with a wrench, purchase a modernized nut with a spring-loaded base that clamps the disk. Chinese junk, pay once for quality AEG,BOSCH or Makita.
2. Types of abrasive wheels and attachments for grinders. Which ones do we use in our work?
2.1. By type of work
2.1.1. Cutting wheels
The name here speaks for itself and the purpose of the disk is intuitive. If you've seen it at least once, you won't be confused. This type of wheel is potentially the most dangerous for the operator.
To cut accurately, you have to look at the plane of the cut with the risk of getting a piece of debris in your forehead if the cutting wheel falls apart into fragments. Below is a photo of an excellent device that allows you to level out this annoying drawback.
2.1.2. Grinding wheels
Designed for grinding surfaces. Welders use it to remove slag from the weld seam. Visually it looks like a very thick cutting disc, but of course it is not. We'll talk about labeling separately.
2.1.3. Roughing
2.1.3.1. Petal circle (petal)
It has a characteristic ribbed surface.
It copes well with roughing work and grinding flat and end surfaces.
2.1.3.2. Peeling attachments
Not abrasive wheels, but I would like to mention these indispensable things when processing hard-to-reach surfaces, for example inside and corners of the U-shaped profile.
It is highly advisable to work with grinding attachments on grinders with a speed controller, as the angular velocity in this case it is not needed and only interferes - it gives strong vibration and knocks the instrument out of your hands.
2.1.3.3. Polishing wheel
The quick-change abrasive material is fixed on a special sanding plate base using Velcro and is used to eliminate small defects.
2.2. By sizes of grinders and discs
Take a look at the instructions for your angle grinder and read which discs you need to purchase. Size - the outer diameter of the disk depends on the size of the grinder for which it is intended and can be:
- 150 mm. Average Bulgarian. It’s no longer suitable for delicate work, but it’s not yet mature enough for professional work. The capabilities of a 150 mm angle grinder are completely covered by its counterpart with a diameter
180mm, therefore a grinder designed for an abrasive wheel with a diameter of 150mm is classified as a highly specialized and not the most practical power tool for widespread use.
115 mm. The most portable option. It is usually purchased for grinding work, since the depth of cut with a new cutting disc does not exceed 30mm. In this case, the disk wears out during operation and its diameter will be even smaller.
125 mm. A popular and most common option for the range of house-dacha work. Successful combination compactness and power with low weight angle grinder. A wide range of circles and attachments for this size are on sale.
180 mm. Copes with relatively thick metal structures and large diameter pipes.
230mm. For household needs rarely required, but to the point. Not suitable for finishing work. Very convenient for processing large masses of stone: cuts concrete beams, stone, brick. It features an impressive cutting depth of up to 70mm and the ability to clean large surfaces. The average weight of such grinders is about 5 kg, which imposes obvious physical limitations.
Thickness cutting disc from 1 to 3.2 mm. It is difficult to give unambiguous recommendations for choice; here everyone decides independently based on the tasks at hand and personal preferences.
The thinner the cutting disc, the easier it is to cut, but the faster the wear. work surface(more often you need to install a new disk) and for some reason they often write on forums that there is a higher probability of destruction when the disk is skewed (the worst thing), but according to my observations, on the contrary, a thin disk is more flexible and “plays” due to the reinforcement.
The smaller the diameter, the higher the operating speed of the angle grinder. For example, grinders 150 and 125 differ not only in the size of the protective casing, but also in the gear ratios of the gear pairs. The use of a disproportionate disc, for example from 150 for a 125mm angle grinder, is strictly prohibited!
2.3. According to the processed material
2.3.1. For metal or concrete
The inscription (“steel” - disc on steel, “concrete” - concrete). In our case, the inscription is duplicated in Russian and English languages. Color (blue - for steel, green - for concrete), sometimes there is a graphic image of the material.
2.3.2. On wood
Never use in Bulgarian saw blades for woodworking! Just recently this was far from the most good idea could only be realized by individual craftsmen who made homemade spacers for installing a circular saw blade on an angle grinder.
Today you can find on sale metal cutting wheels for woodworking that are structurally suitable for your tool in terms of the mounting inner diameter, which creates the illusion that “the manufacturer knew what he was doing,” but not a single intensive care doctor would agree with this.
People get the most terrible injuries when using an angle grinder in chainsaw mode. When it hits a knot, the disc becomes wedged and the angle grinder is torn out of your hands in a split second, flying along an unpredictable trajectory. Here is a similar case, only the role of a knot here was played by a nail.
My friend decided to trim the already installed mdf panels, which were bent due to dampness - the disk from the circular saw was stuck on the grinder.
I sawed off the first two panels normally, but on the third panel I got a tiny nail (finish) and the grinder was torn out of my hands. The result is a completely torn knee and disability for 20 years.
Quote from the forum price-altai.ru
Important! Cut wood only with gas, electric, circular saw or hand hacksaw. In this case, give up the versatility of angle grinders in favor of your own safety!
3.1 On your own blacklist
Cutting yellow-blue wheel Lugaabrasive is a product of JSC "Luga Abrasive Plant" located in the city of Luga, Leningrad region.
The only advantage of the disk is the price, which is offset by the phenomenal speed of its grinding. It is more profitable to buy a more expensive one with a high-quality abrasive and work as usual than to change one Luga abrasive to another every 2 minutes. In addition, there were discs with different cutting edge thicknesses and imbalances, which resulted in terrible geometry in operation.
5. How to work with an angle grinder correctly and safely. Safety precautions (hereinafter referred to as TB)
I won't beat around the bush. The safety precautions for angle grinders are a complete mess. There are no clear official recommendations. According to the instructions, the grinder is grinder, but the range of work performed by this power tool goes far beyond grinding and polishing.
Let's try to understand the security issue based on existing practical prerequisites.
5.1. Nice tool. Why you need to buy it
I am writing absolutely seriously about this aspect in the safety precautions section. Choose a strong one reliable tool. Nice grinder worth everything 1.5 living wage. On average for 1 month healthy person earns in Russia 7.5 minimum wage. per year this 90 minimum wage.
It turns out that for a high-quality angle grinder with protective mechanisms designed by the manufacturer, you need to give everything 1,7% from your annual income. A more than reasonable investment in your own safety. Into the furnace of Chinese and cheap models!
By the way, the average owner invests in car safety (alarm, Casco, etc.) 10% from its cost.
I personally purchased a Bosch GWS. Equipped protective system KickBack Stop, which turns off the tool when the disk jams. That's the whole point. Also, angle grinders produced under the Metabo brand are equipped with a special coupling for a similar purpose.
Most likely Makita also has something, but I won’t say so - I don’t have accurate information on this manufacturer.
Meanwhile, if the grinder is not equipped with automatic engine shutdown when biting the abrasive wheel, then two equally unattractive options are possible:
1) The disk will fall apart and the debris will fly at a linear speed, which we will now calculate for a disk with a diameter of 125 mm and a speed of 12,000 rpm:
Diameter D= 125 mm = 0.125 m
Circumference C= pi*D = 3.14*0.125 = 0.392 m.
Frequency ν=12000 rpm = 200 rps.
Linear speed V= C*ν= 200*0.392= 78.5 m/s
For an angle grinder with a circle diameter 125mm and number of revolutions 12000 rpm the linear speed of the disk fragments will be 78.5 m/s.
Previously there was a calculation error here. Many thanks to Pavel Serkov and Dmitry (unfortunately, last name is unknown) for the letters pointing out the gross miscalculation.
The resulting value is 4 times lower than the initial speed of a bullet from a Makarov pistol = 315 m/s.
2) The disk will hold up and then the grinder will be snatched out of your hands, which will again construction tools turns into a firearm. Here, even without formulas, it is clear that a rotating disk will enter a person like a knife through butter.
5.2. Working without a casing is like playing Russian roulette
The housing should always be between you and the axis of rotation of the tool. Situations will certainly arise when the casing gets in the way, but this is not a reason to dismantle it. Use an angle grinder with quick adjustment of the protection position (I wrote about such a tool above)
In the vast majority of cases, the protective casing works like this:
The disk collapsed, bounced off the casing and the fragments ended up in a zone that was safe for the angle grinder operator, but on the contrary, potentially dangerous for his partner and other people in the work area.
Attention! Sometimes debris can “leak” through the casing or fly in through a ricochet. The presence of a casing is not a reason to forget about the products personal protection.
5.3. Remove all foreign objects
In the mid-90s, when I first picked up a one-handed grinder, I was doing my first renovation in the bathroom, cutting concrete with a diamond, and a piece of clothesline about 1.5 m long was dangling far from me.
I only felt a strong blow on the mask, and in a split second the instrument under the ceiling in the far corner screeched.
Quote from mastergrad.com forum
I think no explanation is needed, organize your workplace properly.
5.4. Personal protective equipment
5.4.1. HEAD. EYES
Safety glasses for grinders. Not a panacea, but better than nothing.
The author knows what he's talking about and had the dubious pleasure of walking around with a red eye while sawing tiles. Didn't fit the size, I had to cut it just a little bit, I was too lazy to put on special safety glasses and caught a splinter in my eye tiles. It's my own fault.
It looks scary, but in terms of time it goes away approximately like a bruise on the skin and does not affect vision. This is one of the easiest and most gentle injuries that can be caused by incorrectly working with an angle grinder.
Safety glasses are not a panacea. Use them only if nothing else is available, but even with safety glasses when working with metal you may be surprised
Chips in the eye. Two words about first aid
The Internet is full of stories of shavings leaking into the eye even when safety glasses were worn. Blinking at the same time will be very painful - the shavings scratch the eyelid and not everyone will be able to endure it until they see a doctor. In this case, proceed as follows at your own risk:
1. Do not touch your eyes with your hands.
2. Lidocaine is dripped from a pipette into the eye (sold in ampoules at the pharmacy). It will burn a little, when the burning goes away and the pain subsides for about 10-15 minutes.
3 . The insides of a cigarette filter are mined. Cut lengthwise at an acute angle.
5. They instill albucid into the eye and go for a check-up with a doctor.
Protective mask - face visor
“Advanced” wear a turner’s shield, which will really protect the eyes from chips, but nothing more. We remember the initial speed of the disk fragments 78.5 m/s and look at the photo from the Hansa:
If I tell you without snot, then the guy was lucky. The circle was cut across the eyebrow and higher on the forehead. Only injured soft fabrics. As a keepsake, there will be a scar 5-6 cm long.
Quote from the guns.ru forum
Consequently, the common shield, which is widely used for working with an angle grinder, only creates the illusion of security and for reliable protection plexiglass should be tens of times thicker, for example here:
I found this mask with a visor made of reinforced plexiglass on the English-language Internet and didn’t even understand how to order it. In addition, delivery can cost as much as a second grinder. Is there anything reliable and affordable for our brother?
Protective shields with steel mesh look cheap and cheerful.
Here protective shield NBT-Euro steel.
The description states:Protects against large and small solid particles with high kinetic energy up to 15 J.
Is up to 15 J a lot or a little? How “large” and “small” particles are we interested in? Let's do some more math:
Muzzle energy- the initial kinetic energy of the bullet at the moment it leaves the barrel. The concept is found in Federal law"About weapons." Calculated using the standard kinetic energy formula:
where m is the mass of the bullet, and v is the initial speed of the bullet.
For small particles:
We take a cutting abrasive disc weighing 0.04 kg. Let it fly apart when destroyed 100 equal parts of equal mass: 0.04/100=0.0004 kg
The mass of one fragment and known to us linear speed substitute into the energy formula:
E = 0.0004 kg * 78.5 m/s (squared)/2 = 1.23 kg m2/s2 = 1.23 J
For large particles:
We assume that the disk shattered in half: 0.04/2=0.02 kg
E= 0.02 kg*78.5 m/s (squared)/2= 61.6 kg m2/s2 = 61.6 J
Indeed, a protective mask with a steel mesh will successfully protect the angle grinder operator from small fragments: 1.23 J.
The result is the same - again we get a piece of the abrasive wheel sticking out from the forehead of the angle grinder operator. Gained kinetic energy 61.6 J a large fragment of an abrasive disc flying out of an angle grinder into 4 times exceeds the maximum permissible 15 J.
It’s a similar story with masks from HUSQVARNA and REZER, and they cost 10 times more than NBT-Euro steel products.
Conclusion: There is no worthy solution on the market of protective construction accessories in the Russian Federation, but we will not give up and turn our inquisitive gaze to protective army helmets.
Mask-1
It’s a funny situation, but only a bulletproof protective helmet can cope with the task of protecting the angle grinder operator’s head.
Reliability is an absolute plus, but availability is a problem - the helmet has been discontinued. In addition, the difficulties of a civilian wishing to officially purchase an army protective accessory are obvious. “From Hand to Hand”, “Avito” and other bulletin boards will help you. Nobody canceled their friendship with warrant officers either :)
Also good option It looks like purchasing a replica (copy) of any army helmet. There are quite a few online stores with such products and visually the result looks great:
ZSh 1-2M with 8mm ballistic plexiglass in two layers
Note: If I’m wrong and reinventing the wheel, and you have ever used specialized construction helmets available for purchase to a wide range of citizens, then I will be grateful and will definitely publish all the reasoned remarks of the form: I used a helmet like this, bought that there, took a blow when the abrasive wheel of such broke then sizes, etc.
5.4.2. HANDS
The casing does not provide a complete guarantee. The last burst disc left my arm a little bruised - a little bloody and all that. The piece hit the casing, flew off to the floor, and from the floor into the hand.
Quote from the popgun.ru forum
Standard cotton gloves will not work. Look for something dense. For example, welding gaiters or split-leaf gloves.
5.4.3. BODY
Need I say that sports tights and a T-shirt do not work with such things?
To work within the framework of safety precautions, you need high-quality, dense and preferably non-flammable (!) workwear. The latter circumstance involves the manufacturer impregnating the fabric with a special composition with a corresponding increase in the cost of the suit.
If your wallet allows, then look towards a “welder suit” in the middle price category.
My enthusiasm for workwear increased significantly after reading some of the remarks. I quote, preserving the authors' spelling:
My patient died from sepsis. I sawed corrugated sheets in my shorts. a stream of sparks flowed along the inner thighs. On the second day I got sick. died 5 days later.
Quote from the guns.ru forum
He was young - “green”. I was cutting something round (unstable) like a (car) muffler. The piece is on the ground, I'm in a deep bend with an angle grinder above it. A sudden gust of wind - and the leg of the overalls gets caught under the disc. The disc of the grinder, winding and cutting the fabric, inexorably, by inertia, creeps upward - to the male “spot.”
With an effort of will, I stopped the grinder's disk (1.5 kW) by squeezing my knees. And so we stand with her and butt heads: Who wins? The off button is somewhere far away in the folds of the fabric. To unplug the cord from the socket you need to take a step with your feet, which I cannot do. In general, it’s good that after a couple of minutes my partner arrived in time.
Result: the grinder didn’t burn, there wasn’t a scratch on the body, my pants were in tatters, I laughed for 2 hours. Since then, I always turn on the angle grinder through an extension cord with a button (I advise you to do the same)
Quote from the chipmaker.ru forum
5.5. Correct technique for working with an angle grinder. Cutting with a grinder. Safe individual skills
5.5.1. Cutting. Start
Never start the grinder by pressing it against the part - the tool can be torn out of your hands. Take a stable position. Turn on the angle grinder at some distance from the material, feel how the machine works.
5.5.2. Avoid being in the plane of rotation of the disk
The first and most difficult rule to master and practically implement. Especially when working with a cutting disc, in order to get to the size it is very convenient to do the opposite - look at the disc and use it as a sight, but at the same time your head and neck themselves, in turn, will be “at gunpoint”. Here's a classic situation:
To move my eyes away from the dangerous line and look at an angle, a simple line drawn with a marker along the cut and adjacent surface helps me. It’s impossible to do absolutely all the work this way, and sometimes I still catch myself thinking that I’ve again gotten myself into the trajectory of the disc flying apart.
However, instilling the skill of working from correct position I minimize the amount of time spent in a dangerous sector and therefore the likelihood of injury.
If you don't like to think in probabilities, then you can minimize the risk with the help of this thing
Super! It's clearly mass-produced, but I haven't come across it on sale. If you have an old vice and a welding tool, it’s not a problem to assemble something similar yourself. Here's a homemade one:
The operating principle is intuitive. Mark yourself, get a foothold, and just know, press the lever as if you were drilling machine or a factory punch and get the following output:
High accuracy.
High security.
The device allows you to completely remove a person from the line of rotation of the abrasive wheel.
5.5.3. Cutting direction
Much has already been written about the notorious direction of rotation of the circle “from itself” or “towards itself” and there is ambiguity of opinions. There, while some people have been sawing all their lives, others consider it categorically unacceptable. My conclusion is clear: Sparks must fly “toward themselves.”
If this is the first time you have picked up an angle grinder, you will intuitively do the opposite, because the sparks make it difficult to see where you are sawing, and besides, showering yourself with sparks is uncomfortable (we talked about the non-flammable welder’s suit for good reason). However:
On my grinder, I turned the gearbox over so that the sparks would fly forward and not backward. Very convenient when the sparks are from yourself. Today the disc jammed and the grinder flew back and sawed through my leg. The cut is not deep, they stitched it up quickly at the emergency room.
And only now I understood why the grinders are set from the factory so that sparks fly backwards. With this direction, when the disc is clamped, the angle grinder is thrown away from you, and not towards you.
Quote from the guns.ru forum
5.5.4. Maintaining a cut
1. Anyone even thin material we cut in several passes.
We enter the existing cut carefully, without touching the walls with the flat surface of the rotating circle.
2. Movements are light and smooth. Feel the aesthetics uniform motion without jerking. In the case of metal, the friction force melts the surface in the contact zone and the melt acts as a lubricating fluid.
If you make a careless movement, the molten film will instantly cool down and you will physically feel the unattractiveness of the “dry” cutting mode.
3. We perform the cut using rocking movements. Thus, the disk forms a small compensation gap for itself, which it will play into if it starts to be pinched. If the cut is carried out under tension, then the disk will have nowhere to bounce and it will fall apart.
5.5.5. We think with our heads
If you have ever sawed a log with an electric/chainsaw or friendship-2, then you probably know how the tool clamps the sawn wood. The same thing happens when working with metal, only the frantic speed of the grinder will turn the scattered disk into a shrapnel shot.
The material will definitely play a role in your work. Figure out where and how.
Remember about the probable rebound and backlash
Be careful in front of and behind the rotating cutting wheel. If you move the cutting wheel away from you in the workpiece, in the event of a kickback, the power tool may bounce back with the rotating wheel directly at you.
From the instructions for angle grinders from Bosh
In addition to disc clamping, rebound occurs:
When the disk plane is pressed against the side surface of the material being processed.
The working disc touches a foreign obstacle or slips off the surface being treated. For example, when cutting along the narrow side of a rail.
5.5.6. The art of undercutting
It is often better to undercut than to cut through. This technique is very common in professional environments.
Examples:
When working with sheet metal, we do not make through cuts. We leave the jumper, bend the sheet and finish it without the risk of clamping the cutting disc. A similar approach can be used when dealing with rolled steel.
If you are cutting pipes in a riser, make an incomplete cut. We burn out the last centimeters - “finish it off” by welding.
For tiles, it is enough to mark a shallow groove on the glossy side and break it. A glass cutter successfully copes with the same task.
5.5.7. Don’t forget about the properties of materials when heated
Any 7th grade student knows that metal expands when heated. Here's the quote again:
The stone was securely fixed, I stood straight. And the disk bit as it was heating up (when it was heating up, you could see how it went straight in waves) ...
Quote from the guns.ru forum
For thorough work when sawing stone and concrete, use a “wet cut” with a grinder. This is a fairly extensive topic that we will leave outside the scope of this article.
5.5.8. Look back at your partner!
Also, do not forget about your own safety when your partner is a person without an angle grinder.
I personally observed a brigade of coven makers from Asia at the facility. The first one saws, and sparks fly down the second’s collar. Like in a joke.
For the same reason, it is forbidden to keep the angle grinder turned on outside the cutting zone. Bend over to unwind the wire, instinctively remove it work area tool to the side - away from yourself and you will cut your partner.
And finally...
6. Smart TB list from chipmaker.ru
On Chipmaker, a specialized resource for working with metal, users have collectively compiled a short and understandable list of TB. I quote it unchanged: