Angle Grinder Sizes | Which is the Right Size for You. Angle grinder rpm

Angle Grinder Sizes | Which is the Right Size for You?

If you are into automobiles, metalworking, or construction business, then you might be familiar with Angle Grinders. They are one of the popular power tools. Angle Grinders are also known as Side Grinders or Disc Grinders. Like other similar power tools, even Angle Grinders come in different sizes. For small and precise cutting, small size is suitable. But for general purpose cutting and grinding, a large size disc is a better choice. What are some popular Angle Grinder Sizes? Which is the right size for you?

In this guide, we will take a look at Angle Grinders. First, we will tackle the basics. Then, we move on to different Angle Grinder Sizes. After that, we will find out the right angle grinder size for the job.

What is an Angle Grinder?

An Angle Grinder is a power tool that grinds steel, wood, or material at a right angle. The motor rotates an abrasive disc at a very high speed, usually between 3,000 to 12,000 RPM.

With this high-speed turning disc, you can grind or cut wood, masonry, and metal. Here are some of the things you can do with an Angle Grinder:

  • Chop off extra of metal
  • Sanding and other finishing (low RPM)
  • Remove old paint and rust
  • During emergency rescue missions

All angle grinders come with a safety guard. This will protect you from flying shrapnel if the disc breaks while operating at thousands of RPM. It will also protect your hands while using the angle grinder.

SAFETY WARNING : Do not use the angle grinder without the safety guard.

The disc attaches to the main grinder unit with the help of a flange and nut. The design of this nut is special as it recesses into the center of the wheel.

When you purchase the tool, you will get a special wrench in the package to tighten or loosen the nut of the disc. Keep this wrench somewhere safe.

Types of Angle Grinders

There are three basic types of angle grinders. They are:

Choosing the correct arbor size for your grinder

It is very rare but you can also find gas-powered angle grinders. As you can see from the names, the first two types have electric motors while the third one has a pneumatic engine.

Corded Electric Angle Grinders are a popular choice for most metalworking jobs. Simply plug in the power cord to an outlet and start using the tool. These power tools are also inexpensive of the three while also being light in weight.

Cordless Angle Grinders are gradually replacing the corded options. Apart from portability, these tools also offer great performance. Due to the battery, the weight of cordless angle grinders is more. Cost is also more than corded counterparts.

Brands like Makita, DeWALT, etc. allow you to use one style of battery with several similar power tools. This might reduce the cost in the long run with multiple tools.

The pneumatic Angle Grinder runs on compressed air. Automobile garages and workshops with several pneumatic wrenches and other compressed air tools will have an angle grinder in their chest.

Angle Grinder Sizes

The size of the angle grinder depends on the job you are working on. When we say angle grinder sizes, we actually mean the diameter of the cutting/abrasive disc.

Apart from cutting discs, you can also use sanding discs and wire wheels with an angle grinder. But make sure that the tool has an adjustable speed as sanding usually requires a low RPM (between 600 and 1000).

Coming to the angle grinder sizes, they are usually available in the range of 4” to 9”, which is about 101.6 mm to 228.6 mm. In this, the 4-1/2” and the 7” angle grinders are extremely popular.

The following list shows the common angle grinder sizes with dimensions in both metric as well as imperial. Note that these dimensions are the diameters of new grinding discs.

Small angle grinders will have higher RPM. For instance, the 4” Angle Grinder from Makita has a no-load speed of 11,000 RPM. They are also very lightweight at 3.7 lbs. to 4 lbs.

The 4” Angle grinders are not as common as the next size i.e., a 4-1/2” is a better option. Speaking of 4-1/2” discs, they are some of the popular angle grinder sizes in the current market.

Just like the 4” options, the 4-1/2” Angle Grinder is also lightweight, at around 4 lbs. to 5.5 lbs. This additional weight is a result of a more powerful motor.

Most 4” Angle grinders have a 6 amp or 7 amp motor. But the 4-1/2” Angle Grinders have an 11 amp or 13 amp motor.

As we move higher in angle grinder sizes, the rotational speed of the disc becomes less. A 5” Angle grinder has a speed up to 10,000 RPM, while a 6” one has a speed between 9,000 RPM to 10,000 RPM.

The 7” angle grinder is another popular size in the “larger” angle grinder category. They have a powerful 13 amp or 15 amp motor and rotate the disc between 6,500 RPM to 8,000 RPM.

What is a Right Angle Grinder Size for You?

Small Angle Grinder sizes i.e., with discs less than or equal to 4-1/2” are suitable for a wide range of cutting and grinding jobs.

angle, grinder, sizes, which, right

You can work on metal as well as masonry with these size tools. You can also work in tight spaces due to their small and compact sizes.

The 7” angle grinder is a medium size while we can consider the 9” and above as a large angle grinder. If you work with a lot of metals, be it aluminum, steel, bronze, iron, and even bricks and concrete, then the 7” angle grinder is an obvious choice.

It has a powerful motor that can deliver excellent performance for demanding and tough jobs.

We recommend you to have a good quality 4-1/2” Angle Grinder as well as a 7” Angle Grinder in your garage or workshop. The smaller one can serve you well for cutting and grinding. While the larger 7” one is suitable for general purpose jobs, including sanding.


Angle Grinders are very popular power tools. We use them in construction, automobiles as well as regular metal working. There are several angle grinder sizes but the 4-1/2” and the 7” options are very common and popular.

In this guide, we saw the basics of angle grinders along with some popular disc sizes. We then saw a brief note on the suitable angle grinder size for a job.

DIYer’s Guide; Top 5 attachment for Angle Grinder

Before diving into the different options of attachment for angle grinder and their uses, it’s a good idea to understand what an angle grinder is and what it does.

angle, grinder, sizes, which, right

Angle grinders are a multipurpose power tool with a fast-revolving disc that can cut, grind, polish, sharpen, and clean a range of tough materials such as iron, copper, brass, brick, tile, stone, or mortar. The tool rotates the discs at a high torque and an average working speed of around 12,000 revolutions per minute (rpm), with some models having variable speeds as low as 2,800 rpm. You may alternate between grinding through metal and polishing metal by adjusting the speed and disc, so make sure the angle grinder is properly equipped for each project’s aim before getting started. The angle grinder is the power tool you need if your profession or pastime includes any sort of material production or surface polishing. Aside from its most frequent usage as a grinder, this power tool comes with a number of abrasive attachments that may be used for a range of chores and purposes. Depending on the material you’re working with and the job you need to accomplish, you can select a proper attachment for angle grinder and get your job done.

How to cut straight and efficiently with an angle grinder

A Vast Selection of Attachments for Angle Grinder

Of course, the applications for which you may use your grinder are limited by your choice of attachment for Angle Grinder and their availability. There are several viable alternatives at this stage. The purpose of the grinder is determined by the disc or wheel it is attached to, which can range from cutting wheels to polishing wheels, grinding discs to flap discs, wire wheels and cup brushes.

o Sanding Attachments for Angle Grinder

Because of its strong engine, accuracy, and high RPM, angle grinders are ideal power sanding equipment. Angle grinder sanding discs are usually circular discs with abrasive material incorporated in them. It’s widely used in the woodworking sector to level surfaces, carve and shape hard woods, and smooth them out, as well as in the metalworking business to remove rust and scratches. These are one of the most commonly used attachments for angle grinders.

o Buffing Polishing Attachments for Angle Grinder

While utilizing an angle grinder as a buffing tool is a wonderful idea, it’s better to use it with experienced hands since angle grinders are quite strong and can spin up to 13,000 RPM, therefore it’s ideal to use a variable speed grinder for buffing and polishing operations. Angle grinder buffing pads are composed of high-quality wool that is known for its wear resistance. The buffing wheel comes to the rescue when it comes to polishing and shining metal surfaces. The polishing wheel, these attachments for angle grinder are used for polishing metal, glass, ceramics, and wood.

o Wire Brush Attachments for Angle Grinder

Wire cup brushes, wire wheel brushes, and end brushes are among the various shapes, styles, and sizes available. Heavy-duty cleaning, deburring, edge blending, and paint peeling are all possible with wire brush angle grinder attachments. For dealing with hard metal surfaces like iron and stainless steel, wire wheel brush attachments with knotted and crimped wires are utilized.

o Attachments for Angle Grinder to Clean Metal

An angle grinder may be used to remove paint, corrosion, and lacquer from metal surfaces. To remove chipped and peeling layers without harming the metal below, use a plastic stripping disc or a metal cleaning wheel. Plastic stripping discs are a suitable choice for removing paint, lacquer, and other non-fused coatings from metal. These discs are composed of nylon webbed material and silicon carbide to give adequate abrasion to remove the coatings off the metal.

A metal cleaning wheel is a superior alternative if you need to remove rust. Metal cleaning wheels are created by twisting together a number of metal wires to make an efficient rust-removal wheel. When this wheel comes into touch with a metal surface while rotating quickly, it scrapes away surface rust to reveal the clean metal beneath. Because these wheels might occasionally discharge tiny bits of broken wire, always use the proper PPE and attachment for Angle Grinder.

Wire wheels easily remove corrosion and peeling paint. Angle grinder attachments with wire wheels and brushes are designed for different sorts of stripping, cleaning, and deburring jobs. Stripping paint or rust off broad, flat surfaces is best done with wire cup brushes. Wire wheels are easier to fit into gaps and corners. Wheel and brush attachments are available in a range of designs. Look through the package to pick one that will work for your needs. Also, check sure the threads on your grinder match the spindle threads. Although the majority of angle grinders feature 5/8-in. spindle threads, there are a few exceptions.

o Attachments for Angle Grinder to Restore Cutting Edges

Angle grinders can also be used to sharpen other instruments, such as lawn mower blades, axes, and chisels, to restore their edge. Equip the angle grinder with an abrasive grinding disc and put the blade of the tool in a vice so you can concentrate on regulating and steadying the grinder’s action. It’s critical to align the grinding disc with the angle on the blade when sharpening tools using a grinder so that the sharpened blade has the same angled cut. Changing the cutting angle might diminish the tool’s efficiency and perhaps cause the blade to break. A grinder is great for swiftly sharpening your tools, but before putting them away, use a sharpening stone to provide a more accurate edge to the blade.

Our 3 Picks of Angle Grinder for Your DIY Projects

Now that you Know there is no limit to do creative projects with the right attachment for angle grinder, it’s only fair to say that all you need to know now is which angle grinder to choose and you are set. Having the best angle grinder means you’ll have a powerful instrument that you can use to handle a wide range of landscaping jobs. Because of their flexibility, weekend warriors and contractors use the best angle grinders all of the time, and they don’t have to be expensive. With picking the suitable attachment for angle grinder, they are capable of a wide range of operations, including grinding, polishing, and cutting. It’s a tiny, portable, handheld power tool that’s easy to pack and move from one job to the next, and it’s available in corded or electric versions. However, with so many possibilities, choosing the ideal one for your desires and needs may be difficult. Here is a short list of 3 angle grinders that would make decision making an easy job for you.

It’s an excellent option for DIYers of any skill level, take this tool, chose the right attachment for Angle Grinder and do whatever DIY project you want to do. It has a peak speed of 9,000 RPMs, a 20-volt lithium-ion battery, and each purchase comes with a fully equipped kit. Each purchase includes 4.5-inch cutting, grinding, and sanding discs, as well as everything else you’ll need to get started on grinding jobs around the house. This product’s cordless design is another big plus because it allows you to operate in small locations without being connected to an outlet or having to worry about tripping over a cable. This angle grinder has a great delayed start mechanism that assures professional-grade results every time you use it. It comes at a very reasonable price, especially when you consider the accessories and kit that come with it. It can cut tile, grind metal, concrete, and rebar without causing harm, and it has a rubberized, ergonomic handle with two settings to keep you comfortable throughout long jobs. The brushless motor provides 53.5 percent greater runtime per charge and is backed by 25 years of expert knowledge.

This angle grinder has a great delayed start mechanism that assures professional-grade results every time you use it. It comes at a very reasonable price, especially when you consider the accessories and kit and attachment for Angle Grinder that come with it. It can cut tile, grind metal, concrete, and rebar without causing harm, and it has a rubberized, ergonomic handle with two settings to keep you comfortable throughout long jobs. The brushless motor provides 53.5 percent greater runtime per charge and is backed by 25 years of expert knowledge. As an added bonus, you’ll receive a slew of features that give you far more control and power than other angle grinders. You’ll receive a two-position handle, for example, to regulate vibrations and keep you comfortable, as well as a direct airflow to blow dust away from any essential sections of the tool, allowing it to last much longer. It also comes with two extra amps than prior models, making it more flexible. The paddle-style switch allows for a variety of grip settings, and the carbon brushes are extremely long-lasting. To protect it from overheating or being overwhelmed with difficult jobs, it has direct motor cooling capabilities.

  • Ronix 3221 Angle Grinder, 2400W, 230mm

The last but surely not the least pick is Ronix 3221 Angle Grinder, 2400W, 230mm. It’s a perfect tool for any DIYer enthusiast just with the right choice of attachment for angle grinder. Its professional 2400W powerful motor enables the tool to work with high performance. It’s one of the most versatile tools among the Ronix tools. Its robust motor allows you to cut, grind or polish all kinds of materials. Ronix 3221 has Ball bearings that are designed to reduce friction, protect the motor against dust, and ensure a long lifetime for the motor and make it work more smoothly. If the motor works under an unusual load, it will be warm and overheated. This angle grinder with its anti-dust switch reduces dust penetration, especially in masonry working conditions. Ronix 3221 has a new locking pin system for easy and fast disc changing and safety mechanism.

Ronix’s ability to change the disc guard quickly, allows the user to place the guard in different working positions. Additionally, this tool has a soft start switch system that ensures the safety of the operation.


  • What can you attach to an angle grinder?Angle grinders are multi-purpose tools that can sand, polish, and sharpen metal, as well as cut tile, stucco, and pavers, carve out mortar, and sand, polish, and sharpen.
  • Is it possible to use a wood blade on an angle grinder?An angle grinder’s blade is a grindstone for polishing or sharpening metal and stone; it cannot be used to cut wood.
  • Is it possible to use an angle grinder as a sander?Yes, converting your angle grinder into a sander is the easiest and most cost-effective way to remove or sand a large amount of surface wood.


Angle grinders come with a variety of capabilities and are available in both cordless and corded variants. Aside from its most frequent usage as a grinder, this power tool comes with a number of abrasive attachments that may be used for a range of chores and purposes. Depending on the material you’re working with and the job you need to conduct, you can select an attachment. Choosing the best attachment for Angle Grinder may be a pleasurable experience when you know what to look for and have examples of what is achievable by good use of them. You may also check through the different buying guides to learn what to look for when you’re out shopping.

Grinding Wheel Safety: Respect The Maximum Speed

One potential source of serious injury in grinding comes from an oversight that is easy to make: operating the wheel in an over-speed condition.

angle, grinder, sizes, which, right

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One potential source of serious injury in grinding comes from an oversight that is easy to make: operating the wheel in an over-speed condition. While a wheel that is run far enough in excess of its rated maximum speed may shatter within minutes of operation, danger may also result from a wheel run just slightly faster than its rated speed. This less severe over-speed condition can cause the wheel to be damaged, and the damage may result in breakage after further use. For example, operating a reinforced, 9-inch diameter, Type 27 wheel rated for a maximum speed of 6,600 rpm on a 7-inch angle grinder with a speed of 7,700 rpm can cause the wheel to crack. This cracking can lead to breakage later.

What other actions lead to an over-speed condition?

The following actions—all of which are not recommended—can also lead to an over-speed condition:

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  • Mounting the grinding wheel on a sander, such as a “pistol grip” air sander
  • Mounting the wheel directly on an electric motor
  • Mounting the wheel on the wrong machine size for that wheel
  • Failing to properly maintain machine components, particularly governors on pneumatic machines and linkages on floorstand machines
  • Using the incorrect air, hydraulic or electric power supply
  • Using an improper speed setting on the machine

Any of these actions sets up a disastrous scenario that could lead to an accident involving serious injury or death.

The hazard of running in an over-speed condition comes from centrifugal force. A result of rotary motion, centrifugal force is what causes a weight on the end of a string to pull the string taught when the weight is swung in a circle. This same force causes the mass of the grinding wheel to be pulled outward from the center of rotation as the wheel is spinning.

Danger comes from the fact that centrifugal force does not increase in direct proportion to an increase in speed, but instead it increases as the square of that speed increase. When rotational speed doubles, centrifugal force quadruples. This effect means that relatively small changes in speed can produce significant increases in force. In the example mentioned, changing from 6,600 rpm to 7,700 rpm multiplies the speed by 1.167. However, the corresponding centrifugal force would multiply by a factor of 1.167 × 1.167, or 1.36.

To take a more extreme example, consider the same wheel with a maximum safe operating speed of 6,600 rpm run on a 5-inch right angle grinder at 10,000 rpm. This represents an over-speed of about 1.5 times the wheel’s designed speed. But the corresponding centrifugal force—and the corresponding rotational stress on the wheel—would be about 2.3 times as much as the maximum allowed.

How to Use an Angle Grinder – 9 Tips to Grind Like a Pro

We got our Pro team together to give you some tips on how to use an angle grinder from basics to some advanced techniques and shortcuts. Angle grinders are controlled by either a trigger, paddle, or switch. They spin a disc at an incredible rate of speed for the express purpose of sanding, grinding, or cutting.

Due to the Rapid advancements in lithium-ion battery technology, the many angle grinder uses have expanded dramatically. This makes it a versatile tool used by a wide range of professionals. With so much flexibility at your disposal, the angle grinder also has a steep learning curve compared to many other tools.

– When Using an Angle Grinder, Protect Yourself!

Before you use an angle grinder, you’ll want to grab some personal protection gear. The reality of the angle grinder is that it’s a loud tool that kicks a whole lot of debris around. Plus, you’re not always grinding or polishing. Oftentimes, the job entails cutting. If you get sloppy with a cutting wheel or simply have bad luck, that wheel could turn into high-speed shrapnel.

For these reasons, you’ll do yourself a favor if you grab some hearing protection, long sleeves, gloves, and something to shield your entire face. You don’t want to take a hot shard of cut-off wheel to the moneymaker, after all. A grinder can also ruin your clothing, so wear protective outerwear if you don’t want pinholes in your clothes from flying hot metal.

angle, grinder, sizes, which, right

Pro Tip: Having a cutting wheel fly apart on you at 10,000 RPM is no joke. There’s nothing you can do when it happens. As a result, you want to always wear a full face shield when using a cutting wheel—even when using a guard. Grinding and using a flap disc doesn’t typically present the same level of danger, so the guard and adequate eye protection are often enough.

– Perform a Ring Test on Grinding Wheels

We recommend doing what’s known as a “ring test” on any grinding wheel before affixing it to your grinder. You can actually do this on bench grinders as well. You basically suspend the grinder wheel from a pencil or other project. Then, gently tap it with the handle of a screwdriver or similar tool—anything not made of metal. Rotate it 180 degrees and do it again. A wheel in good condition should let out a distinctive metallic “ringing” sound.

That metallic ring comes indicates the integrity of the grinder wheel. An internally- or externally-cracked wheel typically stops the vibrations at the damaged point—preventing a clear ring. While the ring test does a good job of giving you an idea of the integrity of the wheel, you also want to follow up with a quick visual inspection.

Once you’re reasonably certain of the integrity of your grinding wheel, go ahead and mount it. The last thing we recommend before starting is to run that wheel on its own (pointed away from your face) for 15-30 seconds. This helps you know (by feel) if it’s properly centered and mounted and if there are any issues with the wheel balance.

– Angle Sparks Away from Your Body

Because angle grinders quickly remove lots of material, lower the risk as much as possible by positioning the tool properly. Using an angle grinder in different applications and with certain attachments calls for different angles. Ensuring sparks and debris fly away from your body reduces your chances of getting injured. Your work clothes will last longer, too!

– When Surface Grinding and Using Flap Discs

For surface grinding, use the flat part of the wheel, maintaining a 20°-30° angle between the tool and the work surface. Position the blade guard at the back toward your body. Use a smooth back-and-forth motion to guide the flap disc over the material. Let the wheel do the work, but feel free to apply enough pressure to ensure you’re being productive.

You can really grind down welds quickly in preparation for painting using this method.

– How to Hold an Angle Grinder When Using Cutting Wheels

You should tackle cutting straight on since you want to use the edge of your wheel to cut into the work surface. Be careful not to bend the cutting wheel in any direction. In this mode, the guard always goes on top to protect you from debris. Wearing a face shield also protects you against premature disc failure. And remember—if the guard isn’t between the cutting disc and your face—move it until it is.

Also—and this might go without saying—never “plunge cut” a cutting wheel into the material. Cutting at the 12 o’clock position is a recipe for kickback and loss of control. Instead, cut downward as shown in the image above.

– Guard Yourself Against Kickback

Kickback occurs any time the grinder wheel stops suddenly. This forces the grinder in the opposite direction of the rotation at the point of pinching. Knowing how to use an angle grinder in a way that avoids this can keep you safe. For cut-off applications, this can happen when the waste piece sags under its own weight—suddenly pinching the blade and causing the tool to transfer all that rotational energy into a kickback event.

Guard against this by properly using blade guards and by supporting your material properly so it doesn’t sag when making an abrasive cut.

You can also experience kickback when using abrasive wheels to grind down material. Corners, sharp edges, and other areas present possible points of kickback that can damage and/or stop a wheel suddenly. Take care to use the auxiliary handle in a way that gives you leverage to protect yourself should this occur. Never EVER use a grinder with one hand!

– Using a Grinder for Light Work or Sanding

For sanding applications, hold the tool at a 5°-10° angle to the work surface. For pretty much all grinder applications, apply only minimum pressure. You want to let the tool and the abrasive accessory do the hard work.

– Your Accessories Need to Match the RPM of the Grinder

Check the manufacturer’s specs when attaching your wheel, disc, or cup. The max RPM on the accessory should meet or exceed the max RPM of the grinder you plan to use. If the rated speed of the accessory is lower than your grinder, you run the risk of the wheel flying apart.

– Never Use Toothed Blades on a Grinder

I don’t care if a company offers circular saw-style blades that fit your grinder. These tools operate at a significantly higher RPM than any handheld circular saw. You NEVER want to use toothed blades on a grinder. That includes those “wood carving chain discs” that use chainsaw teeth as well as anything with carbide-toothed blades. Just don’t do it.

Additional Pro Tips on How to Use an Angle Grinder

If you’ve got any additional tips or tricks on how to use an angle grinder, feel free to leave a comment below.

New 4-1/2”. 6” Angle Grinders

German engineered and manufactured for safety, productivity, and durability. New motor delivers up to 50% more torque for faster material removal and up to 20% higher overload capacity for ultimate durability. Enhanced safety thanks to Metabo’s patented S-Automatic mechanical safety slip clutch which reduces the likelihood of kickback by helping the user maintain control if the accessory jams. Features Metabo’s patented Quick tool-free wheel change system for maximized productivity. Designed with the smallest grip circumference in its class for increased comfort during extended use cutting and grinding applications in metalworking and masonry applications.

WP 11-125 Quick

4-1/2″. 5″ Angle Grinder

11,000 RPM. 11 Amps w/ Non-Locking Paddle

Replaces WP 9-115 Quick (600380420)

Replaces WP 9-125 Quick (600384420)


The powerful LongLife motor delivers up to 50% more torque for faster material removal and up to 20% higher overload capacity for ultimate durability. For cooler operation and extended longevity in demanding working environments the patented motor includes: unobstructed rear air intake, optimized internal air flow, and epoxy coated copper windings that extend outside of the field coil for advanced heat dissipation and protection from abrasion. In addition, the winding protection grid extends the life of the armature up to 5 times in harsh environments.

The grinder’s safety is enhanced by the patented Metabo S-Automatic mechanical safety slip clutch which reduces the liklihood of kickback by helping the user maintain control if the accessory jams.

Productivity is maximized with the M-Quick System for fastest tool-free disc change at the touch of the large spindle lock button.

The ergonomic Non-locking paddle switch is designed to reduce fatigue and de-energize the motor immediately when released for increased operator safety.

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