The Most Powerful Cordless Angle Grinder-A Complete Guide

The most powerful cordless angle grinder are now essential for both DIY enthusiasts and professionals in the field of power tools. The most powerful cordless angle grinder shows how power tools have been used for decades to keep many businesses going.

Angle grinders have been used for years in construction, metallurgy, and home repair. They cut, grind, and clean with a disc that spins with the help of an electric motor or compressed air. These adaptable tools provide the ability to function independently from an electrical outlet.

DIY fans no longer have to be limited by what they can do with their tools. The most powerful cordless angle grinder gives them the courage to take on big jobs. This tool joins them on their artistic adventures, whether they’re making furniture, fixing up the outside of their house, or making a one-of-a-kind yard sculpture.

What is a cordless angle grinder?

Cordless angle grinders, which are becoming more and more useful in many different fields, are a popular choice for professionals and DIYers alike. The Cordless angle grinders are very useful for construction workers, builders, electricians, and metalworkers, among others, because they can be used in many different ways and are easy to use. These strong tools can cut, grind, and clean.

There is an extensive range of materials at your disposal, including metal. concrete, and stone. With speed settings that can be changed and different options for discs, users can get precise and effective results for their jobs. As technology keeps getting better, portable angle grinders are becoming even more effective, durable, and long-lasting. This makes them an even more important tool for any skilled tradesperson to have in their toolbox.

Angle grinders are available in two sizes: 115mm and 125mm. The smaller size is ideal for light-duty tasks, while the larger size is better suited for heavier-duty work. Angle grinders, which can run up to 9,000 rpm, help cut, grind, and polish various materials. Batteries power most of them, making them portable and environmentally friendly.

When selecting a portable angle grinder, please Consider or factor in the size of the workpieces, their material, and how long the battery must last.

The Ultimate Guide to the Most Powerful Cordless Angle Grinder

The purpose of this essay is to provide a comprehensive guide to the most powerful cordless angle grinder available in the market. Cordless angle grinders are essential power tools that offer mobility and convenience without compromising on power. This guide aims to offer in-depth information on the features, capabilities, and performance of the top cordless angle grinders, helping professionals and enthusiasts, depending on their unique needs, make an informed choice.

The Evolution of the Angle Grinder

Angle grinders have been around since the early 1900s, when they were mostly used in the building business. The first angle grinders had to be turned by hand and didn’t have much strength. Angle grinders that were driven by electricity didn’t come out until the 1950s. This made them easier to use and more efficient.

Angle grinders have become more powerful, smaller, and useful over time. AC motors were used in the first angle grinders, but they were not as powerful or movable as DC motors. In the 1970s, side-handle grinders were made, which made them easy to use. In the 1980s and 1990s, brushless motors came out, which made them more efficient and last longer. The most common type of angle grinder right now is one that doesn’t have a handle.

Key changes to angle grinders are motors that are more powerful, designs that are lighter and more portable, safety features, and electric models. Because of these changes, angle grinders are better, more useful, and can be used for more jobs.

Portability and convenience

Angle grinders that don’t need a cord are a helpful tool that can be used for many different tasks and give you the freedom to work anywhere. They are great for building, maintenance, and do-it-DIY projects. Cordless grinders are easy to use, lightweight, and have handles that are made to fit your hand. They get rid of the trouble of tangled wires and extension cords, making them a great choice for people who want a quick and easy way to grind.

Types of Angle Grinders

Disc grinders and cut-off grinders divide angle grinders into two main types:

An angle grinder is one of the most valuable and versatile power tools a tradesperson can have. This is because an angle grinder has different types of grinder wheels that can be switched out based on the job. Because there are so many angles, sizes, and techniques, it can take a lot of practice to learn how to use an angle grinder well. There are different kinds of Angle grinders, but we’ll talk about the two main ones here.

Disc Grinders

An angle grinder is a powerful tool with a quick-spin disc used for cutting metal, but it can also be used for shaping surfaces or creating materials in various jobs or hobbies.

Disc grinders cut, grind, or polish materials with a circular abrasive disc. The disc is linked to the grinder’s spindle and revolves at high rates of up to 12,000 revolutions per minute.  People typically use this method of employment.  as like:

include removing rust, polishing metal surfaces, polishing concrete, and creating shapes from wood or plastic.

Cut-Off Grinders

Cut-off grinders use a smaller, more specialized cutting wheel to cut metal, stone, or other materials. The cutting wheel is made of high-speed steel or diamond and is designed to slice through materials swiftly and efficiently. It is common for people to use this for the following tasks:

Metal pipe or rod-cutting, machine removing bolts or rivets, trimming concrete or masonry, and cutting through sheet metal with a knife.

The Advantages and Disadvantages of Cordless Angle Grinders for Different Applications

Cordless angle grinders are multipurpose power tools. It can be utilized for various applications, from cutting through metal and tiles to shaping and grinding surfaces; these tools are essential for any project that demands precision and efficiency. But what makes them truly unique is their portability.

Furthermore, their small size and lightweight construction allow them to be used for extended periods without generating strain or weariness. They eliminate the requirement to use the power source. These grinders come in various sizes and power outputs, allowing users to pick the best tool for the task they want to accomplish. Cordless angle grinders are now even more efficient and user-friendly because of advances in battery technology that have resulted in longer run times and quicker charging times.

The downsides of cordless angle grinders include a shorter runtime, higher cost, limited power, weight, and battery maintenance. The battery limits the runtime of a cordless angle grinder, which can be an issue for extended jobs or in isolated areas. Cordless angle grinders are often more expensive than corded ones, and they may lack the power required for heavy-duty jobs. Furthermore, because of the weight of the batteries in corded models, cordless angle grinders require regular battery maintenance.

Masterful Applications Revealed

These are just a few of the many applications of high-powered cordless angle grinders. With their versatility and power. This tool is versatile and can be utilized for various tasks.

Metal Cutting and Grinding 

A powerful cordless angle grinder is a versatile tool suitable for metal cutting and grinding, allowing precision and speed in various tasks like cutting thick steel pipes, welds, removing rust, polishing, shaping, cleaning concrete, and masonry. Its size, motor power, and cutting wheel type make it an ideal choice for challenging metalworking operations.

Masonry Mastery

A cordless angle grinder is an extremely useful tool, suitable for masonry work, effectively removing bricks, tiles, and concrete blocks, ensuring pristine concrete. Its diamond blade ensures efficient work, while cleaning and removing grout, making it an ideal choice for DIYers and professionals.

Automotive Awesomeness

The powerful cordless angle grinder is revolutionizing the automobile industry, offering practical solutions for various projects like removing rust, forming metal paneling, painting surfaces, removing brake rotors, cutting welds, washing wheels, and cleaning headlights. This versatile tool is essential for enthusiasts and professionals alike.

Woodworking Magic

Angle grinders are essential tools in woodworking for accurate trimming and edge finishing. They are often linked to metallurgy but can also be useful for carpenters and woodworkers. To use an angle grinder, choose the right disc for the project, such as a flap disc for polishing or a cutting wheel for trimming. Wear safety glasses and mittens to protect yourself, as flames and debris can be deadly. Proper use of angle grinders can elevate your woodworking projects.

The Ultimate Guide to Choosing the Right Cordless Angle Grinder

When choosing an angle grinder, two of the most important factors to consider are power output and torque. Power output measures how much work the grinder can do, while torque measures how much force the grinder can apply. Both of these factors are essential for ensuring that the grinder can handle the tasks you need it to do.

Input Power

Input power is the amount of power a tool needs to work. It is not always a good way to judge its speed, power, or value. This is because the tool loses power through heat as it moves power from the plug to the motor.

For example, a 750-watt grinder might lose more than 100 watts of power as it moves power from the plug to the motor. So, it’s possible that the grinder only needs 300 watts to work.

A grinder’s output power, or the power used to run the tool after heat loss, is a better way to measure how well it works. A tool with a total power of 750 watts will always use 750 watts of power to run.

The Importance of Torque in Speed

Tool speed and torque, which is how hard a grinder turns, show a lot about its power. Most grinders have the same tool speeds when not Currently in use. But, the amount of stock taken off with each turn of the grinding wheel is directly related to how much force (torque) is used to turn the wheel.

For example, each of two grinders may have a speed of 10,000 turns per minute (RPM) when they are not in use. The torque of the grinder is what sets the tool’s RPM when it is being used. When under load, it is easier for the grinder with a higher turning force to keep turning at a high speed. When the lower-torque cutter is working hard, its RPM goes down by a lot.

Battery Life and Voltage

When choosing a cordless angle grinder, there are a few things you need to keep in mind. Two of the most essential factors are battery life and voltage options.

Battery life is how long the grinder can run on a single charge. If you need a grinder for long jobs, you’ll need one with a long battery life.

Voltage options give you more choices for how much power you can use. Higher voltage options give you more power and torque, which is helpful for more rigid materials or complex tasks.

Disc Sizes  

Angle grinders come in various disc sizes, each with its advantages and disadvantages. The most common size is 5 inches, offering a balance of power and versatility for cutting, grinding, and polishing. 4-inch discs are lighter and suitable for tight spaces, but not as powerful for thick materials. 7-inch discs are larger, more powerful, but less versatile, and unwieldy for heavier-duty tasks. The largest disc, 9-inch, offers the most power but is less suitable for indoor use.

Motor Power And RPM  

When selecting an angle grinder for grinding tasks, consider motor power and RPM. Motor power determines the work done, while RPM determines material removal speed. A grinder with a motor of 500 watts and 6,000 RPM is essential, depending on the material type and removal amount. Less power and RPM can be suitable for wood grinding.

The True Value of a Grinder

When you buy a grinder, the price is often a big factor. But when it comes to tools, the phrase “you get what you pay for” can be true. The price tag doesn’t always show some of the most important things about a grinder, like how well it works, how much it costs to run, and how long its tools last. To figure out how much a grinder is worth, you should look at its output power, speed, motor quality, and safety features.

Importance of cordless angle grinder maintenance

Each power tool may have its own rules and safety measures that should be followed to make sure it is used safely. Some of these directions may tell you how to use, store, and take care of the tool. Before you use a power tool, you should read and understand these directions to avoid crashes or damage. Also, check the tool every time before you use it for signs of wear or damage.

Battery Maintenance

If you take care of the battery in a portable angle cutter, it will work better and last longer. Users should pay close attention to any signs of damage. Or use it and change it if you need to. It’s also important to keep the battery in a cool, dry place so it doesn’t get too hot and break. Also, charging and letting go of the battery according to the directions from the manufacturer can help keep it running well. If you take care of the battery this way, the angle grinder will always be ready to use.

Blade Maintenance

Another important thing to do to extend the life of an angle grinder is to take care of the blades. It is important to check the blade often for signs of wear, like dulling or chipping. Dull blades not only make the mill less useful, but they can also be dangerous. Users should clean or replace the blade as needed to keep it working well. Also, you should clean the blade after each use to get rid of any dirt or leftovers that could damage it. If you follow these steps, the angle grinder will keep running quickly and safely.

Safety Precautions

Safety should always come first when using an angle grinder. There are a number of safety rules that should be followed to reduce the chance of getting hurt or having an accident. First, always wear the right safety gear, like safety shields, gloves, and a face shield, to keep falling objects from hurting you. Also, make sure to hold your item tightly in place so it doesn’t move or shift while you’re working.

Troubleshooting

If you are having trouble with a power tool, you should look at the troubleshooting part in the manufacturer’s directions. In this part, you can usually find answers to common problems and advice on how to solve them. It might also tell you how to keep the tool in good shape and fix it if it breaks. By following the fixing steps, you can find and fix small problems on your own, saving you time and money on repairs from a professional. But if the problem keeps happening or seems more complicated, you should get help from a trained technician or call the maker for more information.

The Features of the Most Powerful Cordless Angle Grinder

The most powerful cordless angle grinder is not just a boast. Cutting-edge engineering, starting with the power source, backs it. Here are the features that contribute to its unmatched power:

Brushless Motor A brushless motor can provide greater power for a longer period of time since it is more efficient than a conventional brushed motor.

High-Capacity Battery A high-capacity battery will give you longer run time, so you can keep working without having to stop to recharge.

Variable Speed Control  The grinder’s speed may be changed to suit the work at hand thanks to its variable speed control. This might assist you in protecting the material you are dealing with from harm.

Spindle Lock A spindle lock makes it easy to change discs without having to touch the spinning disc. This is an important safety feature.

Kickback Brake  A kickback brake helps to prevent the grinder from flying out of your hand if the disc catches on something. This is another important safety feature.

User-Friendly and Ergonomic Design of powerful cordless angle grinder

Soft Handles and a Comfortable Grip

Long work hours might cause hand and wrist ache, however ergonomic design takes care of this issue. Soft grip handles are standard on cordless angle grinders, which reduce fatigue and improve control.

Enhanced Visibility in the Work Area

For accurate results, the work area must be clearly visible. With today’s angle grinders, you never miss your target thanks to the enhanced sightlines.

Addition of a Side Handle for Control

A side handle adds more stability and control, especially when using the tool for heavy-duty tasks. To increase comfort, this handle can be modified to the user’s preferences.

Choosing the Correct Disc Size

The work at hand determines the disc size to use. While larger discs are better for heavy-duty operations because they cover more ground, smaller discs are more maneuverable for delicate work.

Start Softly

Because they are strong and quick tools, angle grinders might react a little when they are first turned on. This is very important if the wheel is big and heavy. The motor’s kickback can make the angle grinder jump out of the user’s hands, which could seriously hurt them. The output power to the motor is lowered at first by soft-start technology. It slowly increases until the grinder is fully operational. This power regulation stops the grinder from recoiling during start-up, which makes it safer for the user’s arms and wrists.

Safety Features of powerful Cordless Angle Grinder

Powerful cordless angle grinder are strong instruments that, if not used properly, can be harmful. However, there are a variety of safety features that might help to keep you safe.

Guard–  A shield that shields the user from flying debris.

Trigger Lock– A trigger lock that stops the grinder from starting accidently.

Spark Arrestor–  A spark arrestor is a device that keeps sparks from flying out of the grinder.

Dust Shroud–  A dust veil that aids in the containment of dust and debris.

Vibration Reduction–  Features that reduce vibration that can assist reduce fatigue and hand-arm vibration syndrome (HAVS).

Ergonomic Design– An ergonomic design makes the grinder easy to grip and use.

Difference Between Cordless Angle Grinder or Corded Angle Grinders

Which right-angle grinder to buy depends on what it will be used for and who will be using it. Angle grinders with cords have more strength than those without cords. But cordless types are easier to use and carry, which makes them better for jobs that require you to move around.

When considering corded and portable angle grinders, it’s important to think about how they work and how they get their power. Angle grinders that are plugged into an electrical port get their power from a steady and stable source. This means you don’t have to think about the battery running out or having to charge it.

A connected angle grinder, on the other hand, is limited in how it can be used because of the cord and because it needs to be near an electrical source. On the other hand, portable angle grinders can move around more easily and are battery-powered. They don’t have to be plugged in and can be used in places where there are no electrical outlets.

This makes them perfect for projects outside or at work. Also, portable angle grinders are light and easy to carry, which makes them great for workers who have to move around a lot. On the other hand, portable angle grinders have short battery lives and need to be charged often, which can be a pain when used for long periods of time. Overall, the choice between a corded angle grinder and a portable one depends on the user’s wants and tastes.

Ultimately, the best way to choose between cordless and corded angle grinders is to consider your needs and preferences. If you are still unsure, it is a good idea to consult with a professional.

The 5 best portable angle grinders are our top picks.

Angle grinders are powerful tools that can do a lot of different things. We’ve picked the five best portable angle grinders on the market so you can find the right one for your needs. These grinders are all powerful, easy to use, and affordable. Whether you’re a beginner or a pro, we have a grinder for you.

DeWALT Max 4 1/2 inch Angle Grinder – Swift Wheel Change

This DeWalt DCG412B Cordless Angle Grinder is a great choice if you need a strong angle grinder for heavy use. It can be used for grinding, cutting, and a lot of other things. It does a great job of cutting curves and has a quick wheel release so you don’t have to stop and use a wrench to take the wheel off.

This will save you time and work, and it will be easy to move from one job to the next without stopping. The two-finger trigger switch and lock-off button make it easy to use and more comfortable to hold. The two-position side handle makes it easier to control, more comfortable, and more flexible.

The DCG412B is part of DeWALT’s 20V Max system, so it can be used with any of the 20V Max lithium-ion cells. Users who already have DeWALT electric tools can share batteries so they don’t have to buy as many different types of cells.

The DeWALT is less expensive than the more expensive DCG416B. This makes it easier for Pro and people who work with light metal to get. Still, it is made very well and comes with a 3-year guarantee.

key features

•  Cordless angle grinders with 8000 RPM can be used for cutting and grinding jobs that require a lot of power.
• Quick-change wheel removal makes it possible to change wheels without a wrench.
• The tool-free guard makes it easy to move and change the guard quickly.
• Two-finger trigger switch with lock-off button makes it easy to turn on and hold.
•  The 2-position side handle gives you better control, more comfort, and more ways to use it.
• The 20V tool requires a separate battery and charger, which item needs to purchased.
•  Two positions for the side handle give you more power, comfort, and options.

Makita 18v 125mm Brushless Angle Grinder – Automatic Turn-Off Tech

Makita tools are made just as well as DeWALT, Boch, and Milwaukee tools. But at just under 6 lbs. It’s quite big. Still, this power tool is strong and durable because of how much it weighs. Rest assured, Makita will not fall apart.

The top speed of 8,500 RPM stays steady even when the engine is working hard, and it’s hard to stop. Makita’s electric brake lets it stop in less than two seconds. This makes it easier and quicker to put down After grinding, you can be more productive since you don’t have to wait for the car to stop. In this way, the Makita is about the same as the Boch, but the Boch seems to stop faster based on the grinding wheel.

The soft start keeps the gears in good shape for a long time and stops kickback. Plus, the soft, ergonomic body makes it easier to hold on to and reduces the effect of movements on the arms, which makes grinding less painful.

You will get a lot of use out of the Makita DGA504Z. It has a 3-year warranty and a motor that doesn’t need to be cleaned.

The most important thing about the Makita is that the speed can be changed. Not many compact angle cutters have this feature. But if you want a Makita with a fixed speed, the Makita DGA504Z is less expensive and has the same other features.

It’s also small and light, which makes it easy to move.

key features

• 125mm brushless motor has the most power and will last the longest.
• Automatic control of speed for the best performance.
• Anti-restart feature to keep things safe.
• Soft start: This feature lowers the force when the tool is first turned on, which can help keep crashes from happening.
• Electronic power controller to protect against overloading.
• Extreme Protection Technology (XPT) to keep out dust and water.
• Easy to handle because it is small and light.

Black+Decker 18V BCG720N-XJ – Compact capability

Black+Decker’s BCG720N-XJ is a neatly small angle grinder with a powerful 8600rpm no-load speed (8000rpmwhen used). It has 125mm spinning discs that let you grind more ground faster and give you a good balance between depth of cut and freedom.

The die-cast aluminium body keeps the weight down to just 2.6kg, so you don’t have to worry about muscle tiredness stopping you from grinding. The three-position handle and side bar make it easy and accurate to use.

The 18V battery that powers this versatile tool is part of B+W’s 18V PowerConnect line. It works with all other tools in the bar, so if you have a lot of Black+Decker tools, you won’t need to buy more batteries. But this is a big one, but it doesn’t come with a battery or charger. Most angle grinders are sold “bare,” so you’ll have to buy those things separately, which will make the price higher.

On the safety side, it has a cover that keeps sparks and dust out and a no-volt release switch that stops the unit from turning on by accident when the battery is changed. This means that even if you’re not the safest person, the team is safe in your hands.

The small but robust Black+Decker BCG720N-XJ is great for cutting, grinding, and cleaning odd jobs around the house. It has a spindle lock that makes changing discs easy.

key features

• 18V lithium-ion battery with a 125mm (5″) disc size for mobile use
• 8,600 RPM at no load.
• Start slowly for a smooth ride.
• Anti-restart feature to keep things safe.
• For easy disc changes, the guard can be taken off without tools.
• Ergonomic shape makes it easy to use.
• Comes with a 125mm cutting disc.

Bosch GWS 18V-7 Professional – Heavyweight versatility

The GWS 18V-7 Professional portable angle grinder from Bosch is a handy solution that combines strong 18 V cutting power with a small size. It has a strong brushless motor that gives the same amount of power as a 700-watt wired angle grinder. This gives users all the power they need to get great cutting results.

It’s easy and comfortable to work with because it’s light, has a slim grip, and doesn’t have a key guard. This angle grinder is well-balanced and has a slim handle to make it easy to use. It works well for cutting a lot of different things.

The Bosch GWS 18V-7 Professional is a serious grinder. It’s made for workers who use their tools every day for work, not just for fun. This stylish grinder is made to last and get the job done, no matter how hard it is.

With a huge no-load speed of 11,000 rpm, the Bosch has a lot of power and can spin those 115mm discs faster than anything else out there. This gives you a removal rate that is second to none and is on par with many of the best electric options in terms of power.

The GWS 18V-7 Professional is small and lightweight, with an ergonomic slim-grip handle that makes it easy to use in tight spaces. It has a brushless motor that helps the battery last longer and keeps the Bosch grinding long after its brush-carrying competitors have stopped working.

If you want to step up your angle grinding game, look no further than Bosch. It can cut through bricks, tiles, and metal just as well as it can cut through metal. It also has a feature called “restart protection” that prevents unwanted spins when you change batteries.

The box comes with the GWS 18V-7, an extra handle, mounting flange, safety guard, quick-clamping nut, and a two-pin wrench.

It works with all 18-volt batteries and chargers from Bosch Professional, as well as the GDE 125 EA-T dust extractor from Bosch. Also works with AMPShare, a union of batteries from different brands.

key features

•  Brushless motors work well and last a long time.
• 18V battery for freedom from cords
• 11,000 RPM at no load for a wide range of uses
• Keyless guards make it easy to change discs
• Safety protection for restarting
• Start slowly for a smooth ride.
• Dust insulation to make things last longer
• Easy to handle because it is small and light.
• Carrying case makes it easy to move and store
•  Warranty for 3 years

DeWALT MAX FlexVolt Avantage 4 1/2 to 5 in. Angle Grinder

The DEWALT DCG416B is a powerful and flexible angle grinder that is great for both pros and people who like to do things on their own. It has a brushless motor that can put out up to 1,550 watts at 9,000 rpm. This makes it great for a wide range of grinding, cutting, and cleaning tasks.

On the other hand, DeWALT is just as well made as Milwaukee, and their safety features, such as the kickback brake, e-clutch, and e-switch protection, are just as secure. The e-clutch stops the motor in less than a tenth of a second if the pitch happens.

DeWALT says that their “FlexVolt Advantage” batteries have up to 54% more power. Even though it’s hard to say for sure, the FlexVolt batteries do improve the power in a noticeable way. So, the DeWALT + FlexVolt is a good choice if you need a very powerful angle grinder. Pricey, but good.

Like the Milwaukee grinder above, the DeWALT DCG416B is a skilled angle grinder. It costs a lot and has a lot of power. But, unlike Milwaukee, it has “just” a 3-year guarantee. This is a normal warranty length, and some brands give even shorter ones.

key features

• When a FLEXVOLT battery is used with the FLEXVOLT ADVANTAGE technology, it gives up to 54% more power.
• The brushless motor can put out up to 1,550 watts at 9,000 rpm.
• Switch with a paddle for easy use
• In case of a return, the return Brake stops the wheel quickly.
• When a wheel pinch is noticed, the E-CLUTCH® System turns off the motor on its own.
• It’s part of the Perform and ProtectTM line of products, which comes with a 3-year limited guarantee.

Overall Conclusion

The most powerful electric angle grinder is one with a brushless motor that can reach up to 10,000 RPM. This makes it easy to take and gives it a long power life. Other portable angle grinders have more power and a longer battery life, so they can be used for a wider range of jobs. The most powerful cordless angle grinder for you will depend on your wants and your budget. Look for a grinder with a brushless motor if you want the most power, but there are other choices if you want to spend less.

FAQs

Q: Why is it important to have a strong powerful cordless angle grinder?

A:  A cordless angle grinder is crucial for professionals and DIYers due to its quick, easy removal of material, versatility, reliability, and ability to handle heavy-duty tasks. It ensures safety, reduces fatigue, and can accommodate different disc sizes, making it a valuable tool for cutting, grinding, and polishing.

Q: What types of materials can be cut or ground using a powerful cordless angle grinder?

A:  Angle grinders that don’t have cords are very useful tools that can be used to cut and grind a wide range of materials, such as metal, wood, concrete, brick, stone, and plastic. The tool is right for a certain job based on the type of material and the right disc.

Q: Why is it important to check a portable angle grinder’s RPM rating?

A:  The RPM (Revolutions Per Minute) number shows how fast the grinder’s disc spins. To make sure the grinder works safely and well, it’s important to match the RPM of the grinder with the recommended RPM of the grinding or cutting disc. Using the wrong RPM can cause crashes or make the machine work less well.