What Size Angle Grinder Do I Need?

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Whether you’re a carpenter by trade or just dabble in some DIY around the home, you’ll probably agree that one of the most frustrating moments you can experience is when you have the wrong tool for the job you’re trying to complete. While some tools can be adapted to work differently, others are fairly specific to their purpose and difficult to substitute. Angle grinders are one such example and are common tools found in any toolbox. 

These versatile tools range from grinding through tiles to polishing metal. Despite its versatility, there is no ‘one size fits all’ option since each has its restraints. Choosing the right option for the jobs you intend to use it for will make your work that much easier and safer. Below we’ll go through some of the most common options and their basic specifications to help you make the best choice. So without further ado, let’s jump right into it.

Angle grinder sizes

What Size Angle Grinder Do I Need? Grinder Power Tool

Angle grinders come in various size options starting from 4 inches, all the way to the 9-inch heavy-duty machines found in large factories. They are generally grouped into three categories: 

  • Small angle grinders
  • Medium angle grinders
  • Large angle grinders 

Below, we will take a look at each one of these in more detail.

Small angle grinders

This includes machines that range between 4 – 5 inches. They require up to 120 volts to operate optimally and can generate between 720 – 1440 watts of power. Small angle grinders are ideal for DIYers and odd jobs around the workshop because they are light, portable, and come in a battery-operated option. 

Medium angle grinders

 6 – 7 inch angle grinders are medium-sized and are seldom found in a battery-operated option. These tools range between 1400 – 1800 watts requiring 120 volts. Due to their larger size and power, medium angle grinders are slower than the smaller variants, generating in the region of 5000 – 8000 RPM on average. They’re also significantly heavier, averaging anywhere from 12 – 20 pounds. 

7-pound angle grinders are perhaps the most common industrial tool and are more likely to be seen in carpentry, metal, and woodwork factories. 

Large angle grinders

8-inch angle grinders do exist but are not generally a very popular choice. For large operations, 9-inch angle grinders are usually the go-to option. These large tools use a 15 AMP motor delivering in the region of 6000 – 6500 RPM at 230 volts. Large angle grinders are designed for heavy usages such as welding and construction work since they can easily devour through the thickest stones and metals. 

What Size Angle Grinder Do I Need? Grinder Power Tool

Angle grinder characteristics

There are four major characteristics that angle grinders possess, differing from smaller to larger models. Here’s what you need to check when making your decision: 

  • Size – As we covered already, this ranges from 4 to 9 inches.
  • Speed – Smaller grinders generally spin faster than larger models. This is important as the speed can affect how clean the eventual cut ends up. 
  • Weight – Small grinders usually weigh around 4pounds, while a 9-inch grinder can weigh in the region of 20 pounds. 
  • Power – Harder metals require more power. However, more power generally adds to the weight and decreases the speed. 

Before choosing your angle grinder, take a moment to consider what the most common jobs are that you require the tool for and choose accordingly. 

Angle grinder discs

Angle grinder discs come in three types: 

  • Flap discs – These are the most common type of discs used for finishing work, removing old paint from cars, and removing sharp edges. Unlike some of the other options, these discs don’t produce a large amount of sparks and can work at shallow angles or even on flat surfaces. Flap discs generally range from 40 grit which is great for grinding metal quickly, to 80 grit, which is better for shaping. 
  • Wire wheel discs – These discs are ideal for shining metal, but they can also be used on wood and rubber as well. Wire wheel discs provide a smooth and polished surface while minimizing scratches. 
  • Diamond discs – As the name suggests, these discs blades have diamonds fixed to the cutting edge, which makes them especially good at cutting harder, abrasive material. Diamonds are one of the hardest substances in the world; therefore, these discs are extremely sharp and are capable of cutting through stones and bricks with relative ease.

The disc you choose will be dependent on the job you are using the angle grinder for.

Angle grinder safety 

Now that you know the different sizes and types of machines available, you need to ensure that you take the necessary safety precautions while working. Here are some top tips to keep in mind: 

Warm up the machine – Whenever you start your angle grinder, allow it to run for a minute or two. This allows the machine to warm up and also lets you get a feel for the vibration and power. 

Disc size and attachment – Always use the prescribed disc size and ensure that it is fastened properly using the pinwheel. Using a disc that’s too big will cause the disc to loosen quickly and possibly detach. This can be very dangerous. Therefore, it’s a good idea to check that your disc is fastened fairly regularly.

Safety guards – Never ignore the safety features on your grinder. They are there for a reason, so you should never remove them or continue work if they have broken off. 

Protective gear – Wearing suitable PPE is highly recommended. These items will help protect your eyes and hearing, and your extremities. Never wear baggy clothing and always tie long hair back to avoid getting tangled in the angle grinder disc. 

Match RPMs – Always check the RPM rating of the disc you intend to buy and ensure that it equals or slightly exceeds your angle grinder’s RPM. 

Keep control – No matter how comfortable you feel using an angle grinder, you should never take the potential dangers lightly. Always use two hands when operating the tool, ideally with your dominant hand at the back of the machine and the other hand on the side handle. In addition, be aware of your finger placement when carrying the machine. It would be best if you never had your finger on or near the power button. 


Angle grinders are an essential tool for any toolbox. Due to their versatility, these tools can be used for anything from grinding through metal to filing paint off cars. Angle grinders differ in four major categories: size, power, weight, and speed.

Smaller grinders tend to weigh less and spin much faster than larger ones, which are preferred for large-scale jobs. When operating any angle grinder, it’s vital to ensure that you wear suitable PPE and use the machine correctly to minimize potential danger or injury. 

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