- Main groups of angle grinders
- Consumables used
- Weight and power of angle grinders
- Design features of angle grinders
- Choosing a one-hand angle grinder
Angle grinders (angle grinders), or, as they are still commonly called “grinders” – one of the most popular and irreplaceable tools both in production and in the home workshop. And this is provided that the design of the angle grinder itself is extremely simple and has existed without any special changes for quite a long time. But let’s talk about everything in order.
The very name “angular” comes from the type of gear that is used on this tool. The angle gear has been used for a very long time and in various fields of technology. Suffice it to recall the most common windmills, where the wind energy was transmitted to the millstones precisely through a gearbox of this type, as in angle grinders. There is no specific information about who exactly belongs to the “palm” in the invention of the angle grinder. In technical museums in many countries of the world, you can see a lot of a wide variety of devices that can be considered the progenitor of the angle grinder. They differ from one another most often only by the drive. There are devices with mechanical, pneumatic, gasoline and even steam drives. Modern angle grinders are electrically and pneumatically driven.
Electric grinders can be powered both from the mains and from batteries. And nevertheless, it is difficult to determine who exactly was the first to start producing angle grinders in the form in which we are used to seeing them on construction sites, on store shelves. So, in the early forties of the last century, the German company AEG (Allgemeine Elektrizitdts-Gesellschaft), or in translation “General Electric Company”, began the production of the first grinding and polishing electric machines. You may be interested – why do we remember AEG now? The answer is very simple – it was from this company that back in 1966 the Bulgarian plant “Elprom-Lovech”, which produced a wide variety of electric motors for both industry and household use, acquired a patent for the production of an angle grinder.
In the early 70s of the 20th century, the Bulgarian power tool was actively supplied to the territory of the Soviet Union. It is precisely since then that the name “Bulgarian” has been assigned to the angle grinder. As for the plant itself, we still widely use its products. Over time, the ELTOS trademark appeared, which operated successfully until 1996 and was acquired by the German company SPARKY. Naturally, at the same time, the tool was also produced at other enterprises, for example – “REBIR”. It is one of the oldest enterprises in the territory of the former Soviet Union, which was founded in 1944, and since 1966 it was transformed into the Rezekne Construction Tool Factory “Latgale” and after the construction of a new production line, it began producing a wide range of tools. But Bulgarians were the first to enter the power tool market of the Soviet Union …
Here is a small historical excursion. Now we will try to find out the features of the device of angle grinders, since their cost directly depends on this and, knowing this information, we will choose for ourselves the most acceptable options for tools.
Main groups of angle grinders
First of all, let’s split our angle grinders into two big groups – professional and household angle grinders. As with any other instrument, the main indicator for dividing into these groups is the operating mode of the instrument (duration of work). Even angle grinders, regardless of whether they are household or professional, can be divided into two more groups – one-hand angle grinders (angle grinders with which you can work while holding it with one hand) and two-hand angle grinders. The main indicators in these two large groups will be – the diameter of the cutting wheel, power, weight of the tool itself and the various options that the tool has (anti-vibration protection, balancing, rotary handle, SDS nut, etc.). So let’s look at each parameter of these tools in more detail..
The smallest cut-off wheels used on angle grinders are usually mounted on cordless tools, such as the BOSCH GWS 14.4 V Professional cordless angle grinder with SDS-pro system. The diameter of both the cut-off and grinding wheels for this angle grinder is only 100 mm.
A distinctive feature of this tool is a special fastening mechanism for the working tool (circle). A special mechanism is integrated into the cut-off (grinding) wheel, which allows changing the wheel without auxiliary tools. However, this has not only positive, but also negative properties..
The tool is designed in such a way that it allows you to use only BOSCH consumables. Wheels and other consumables from other manufacturers simply cannot be fixed.
It should be noted that for this angle grinder, the choice of consumables is very small – only a few types of grinding and cutting wheels. More convenient, in my opinion, are cordless angle grinders from DeWalt, for example DC411KA. This machine allows the use of standard 125 mm discs. There are also wheels for manual angle grinders with a diameter of 115, 150, 180, 230, 300 mm. The latter (with a diameter of 300 mm.) Are used in special cutting machines, for example, in a BOSCH GWS 24-300 J cutting machine, or on a CM12Y universal cutting machine HITACHI. Moreover – all wheels and other consumables for angle grinders are made with a bore of 22.2 mm, which makes it easy to use any consumables from different manufacturers. We’ll talk separately about consumables another time, because this is a fairly extensive and very interesting topic..
Weight and power of angle grinders
Unfortunately, it is extremely difficult to achieve high power and light weight from a tool at the moment. Manufacturers go to all sorts of tricks that allow, at least to a small extent, to reduce the weight and size of tools without compromising its quality and safety for the consumer. So, for example, to reduce the dimensions of the armature and stator of electric motors in some products, a non-standard wire is used. If a round wire is used to make a conventional electric motor, then in order to achieve a smaller volume and the same power, some products use square wire. This allows for a tighter winding and thus reduces the size of the tools. Alas, it is not so easy to reduce the weight of the tools.
Let’s take a simple example. The G23U2 angle grinder with a power of 2000 W, a diameter of the used circle of 230 mm, has a weight of 4.3 kg, and the G23UBY angle grinder, which is only 600 W more powerful (2.6 kW), has a weight of 5.3 kg. Another feature – angle grinders with a circle diameter of 180 mm., Have the same weight and dimensions as angle grinders with a circle of 230 mm. So for those who are going to purchase a powerful, but small-sized angle grinder, such a tool simply will not work..
Design features of angle grinders
But now is the time to talk about what the device of an angle grinder is. It is only at first glance that this tool seems simple and does not contain any complex technical solutions. In fact, everything is different.
First of all, it is very important to choose more than just a powerful tool. It is important to choose an instrument that is safe for your health. And the manufacturers took care of this – both one-hand and two-hand angle grinders of different classes are now equipped with special vibration-proof inserts. This not only allows you to more quickly and comfortably perform the task, but also prevents the development of all sorts of so-called industrial diseases, which are directly related to vibration..
Many angle grinders are now equipped with special quick-locking nuts (SDS), which, unlike standard nuts, allow discs to be replaced without the use of keys. At first glance, this option is not so important, but when your circle is tightly tightened and you cannot remove it with keys, you will definitely remember that such quick-locking nuts almost always allow you to avoid such troubles.
In addition, due to the fact that the vast majority of angle grinders have powerful electric motors, the so-called “soft start” is installed on the tool. This option will allow you not only to save the wiring in your apartment or in the country from short circuits and overloads, but also save the gears in the gearbox of your angle grinder from impacts at the moment of starting. Some manufacturers, in addition to the “soft start” in the gearbox of the angle grinder, install special couplings to avoid possible jerks and shocks. For example, such couplings are equipped with MAKITA 9562 CVH angle grinders.
Angle grinders are designed to work in harsh conditions – abrasive and metal dust will very quickly destroy an electric motor that is not protected or has poor protection. Different manufacturers have different approaches to the issue of protecting electric motors of angle grinders from overloads and the effects of an aggressive environment. Some install special motor protection against overload, others, such as METAVO, have specially developed electric motors for their tools with protection of the windings from all kinds of mechanical particles, such as in the W 10-125 QUIC angle grinder.
Such things as play an important role in ensuring convenience in work:
- pivoting rear handle,
- the ability to install the front handle in 3 positions, or the ability to rotate the angle grinder,
- turning the protective cover of the angle grinder without using auxiliary tools,
- automatic balancing of the working disc, thanks to the use of specially designed bearings,
- long electric cord of the machine, which allows you to work without the use of extension cords,
- speed regulator and electronics that maintains power regardless of the load on the tool and much more.
It is also worth noting that even the plastic from which most cases of electric angle machines are made not only withstand significant mechanical loads, but also can withstand heating of the case up to 140 degrees. The motor and the body of the angle grinder must be warm during operation. A rise in temperature to certain limits does not mean that the tool is broken..
Choosing a one-hand angle grinder
Knowing all the features of one-hand angle grinders, let’s choose a product that we can actively use in our work, for example, when repairing an apartment. The main selection criteria are sufficient engine power, both for cutting metal and for making strobes for electrical wiring in concrete, the possibility of using a variety of replaceable accessories. We will not pay attention to the products of the lower price segment, and this is not at all because cheap products cannot be of high quality. It is simply much more profitable to purchase a more expensive tool that will last longer than a cheaper one. Moreover, if we consider that we are going to purchase a sufficiently versatile and safe angle grinder in operation, then it must be borne in mind that all additional options have a certain cost. However, in specialized trade, you can always count on some discounts, in addition, manufacturers periodically arrange price promotions for their instruments..
Our attention was attracted by the products of the BOSCH company, which traditionally represents one of the widest assortments of its products on the market. This is a professional angle grinder GWS 10-125 PROFESSIONAL, as well as a household angle grinder PWS 10-125 CE. In addition to these two machines, we also decided to consider the products of the HITACHI company, namely the Hitachi G13YD angle grinder and the MAKITA 9565CVL angle grinder.
All these machines have an engine power from 1000 to 1400 W, a circle diameter of 125 mm., They all weigh about the same. All grinders are equipped with self-shutting off carbon brushes, which prevent damage to the electric motor collector, the cord for all tools is of sufficient length, which allows you to work with tools without the use of carriers. So how do you choose a worthy helper? First of all, let’s look again at the characteristics of the machines..
Angle Grinder GWS 10-125 Professionalhas improved cooling of the electric motor, the protective cover can be rearranged without the use of auxiliary tools by pressing a special locking button, the tool kit includes a special side handle with vibration damping system Vibration Control.
It is possible, using a screwdriver, to reposition the gearbox of an angle grinder by turning it 90 degrees. Power is 1000 W, wheel rotation speed is 11000 rpm, weight is 1.7 kg. The cost of this angle grinder is about 4000 rubles.
Angle Grinder РWS 10-125 CEdiffers from its professional counterpart in that it has the ability to adjust the speed in the range from 2800 to 11000 rpm due to the built-in electronic stabilization system Constant-Electronic. The casing can also change its position and be fixed without the use of auxiliary tools, but the principle of the locking mechanism is somewhat different. The delivery set also includes a vibration-damping handle, the weight of the tool is 2.1 kg, the power of the electric motor is 1020 W. The gearbox of this angle grinder can also be adjusted at a 90 degree angle. Moreover, its cost is almost the same as that of a professional typewriter with the same power..
Angle grinder Hitachi G13YDhas a higher engine power – 1100 W. In addition, the machine is equipped with a soft start and a device that maintains power regardless of the load on the tool, but this angle grinder has no speed control. In addition, the machine does not have a vibration-proof handle, the weight of the tool is 2 kg, the number of revolutions is 10,000 rpm. The cost of this angle grinder is about 4500 rubles.
The last machine that will be discussed is MAKITA 9565CVL. This is a very interesting tool, which in its essence simply has no competitors, since no other manufacturer manufactures angle grinders with similar parameters. It should immediately be noted that this is the most powerful and expensive angle grinder of all those that we reviewed above. Its cost is 6800 rubles.
First of all, MAKITA declares that this tool has been specially manufactured to work in difficult conditions and with high loads. It is for this reason that the maximum number of revolutions is 6800 rpm. The built-in electronics allows the user to reduce the speed to 2000. The machine is equipped with a special plastic gear cover (removable), which makes it more convenient to hold this machine in the hands when polishing any surfaces. In addition to the fact that the angle grinder is equipped with a soft start (starting current limiting device), a special drive system with a patented slip clutch (SJS) was additionally used, which, in combination with a soft start, very effectively prevents tool jerking during operation and during starting. It is also worth noting that with high power, this angle grinder has a fairly low weight – only 1.8 kg.
This is the difficult choice we have to make. However, before finally deciding on the purchase, we decided to additionally consult at service centers about the terms of warranty service, the availability of spare parts, and learned the following information. BOSCH provides a 3-year extended warranty for manufacturing defects for all its professional tools, subject to periodic (paid) service at an authorized service center. Household tools have a 2 year warranty. MAKITA and Hitachi provide 1 year warranty for tools. And we managed to find out one more fact. It turns out that the professional and household BOSCH angle grinder, which we considered above, have the same electric motors, gearboxes, carbon brushes. It turns out that for a lower cost, we can purchase a household angle grinder, which will differ from the professional only in the color of the case, but at the same time has more different functions and better protection. True, you have to sacrifice one year of warranty. The MAKITA product is also worthy of attention, however, a home craftsman is unlikely to be able to fully realize the full potential of this machine at home, and it costs much more than other products. It is for this reason that we have chosen the PWS 10-125 CE angle grinder as our home tool. A professional electric motor and gearbox, a large selection of spare parts, wide application possibilities due to built-in electronics, the presence of a modern vibration protection system allowed us to make this choice.
We did not choose a two-handed angle grinder – the selection criteria would be practically the same, but in the household this tool would have to work less than a small “grinder”. I hope that we helped you learn more about such a tool as an angle grinder (angle grinder) and in the near future we will introduce you to consumables and additional equipment that is used when working with angle grinders. I would like to remind once again that when working with any tool, it is imperative to comply with safety requirements. Successful work to you.