How to Use an Angle Grinder

An angle grinder is a versatile tool that makes quick work of multiple materials. Learn how to take advantage of all its DIY potential.

Next Project
Time

An hour or less

Complexity

Beginner

Cost

Varies

Introduction

Learn to use an angle grinder to cut tile, mortar and pavers; make quick work of rust and loose paint removal; sharpen blades; and cut or grind steel.

Tools Required

  • Angle grinder

Materials Required

  • Flap disk
  • Masonry Disc
  • Paint stripping wheel
  • Thick cut off wheel
  • Thin cut off wheel
  • Wire wheel disk

An angle grinder is one of those power tools that when you need it, you need it!

When most think people of an angle grinder, metal and sparks come to mind. But did you know an angle grinder can also come in handy with wood, cement and acrylics? Once I got past the intimidation factor, the angle grinder became one of my favorite tools.

There are some basic rules for using an angle grinder, and most have to do with safety. Allow me to open the door for you and show you how to use an angle grinder — the right way.

Project step-by-step (5)

Step 1

Use proper safety equipment

An angle grinder is a high-speed rotating tool. That means it’s loud, spits things out, and can hurt you or someone around you if you’re not safety conscious.

Before using an angle grinder, take the following precautions.

  • Eyes: Start with safety glasses. Wear a full-face shield on top of the glasses to avoid smaller particles or sparks coming in through the side.
  • Ears: Use ear protection with any tool louder than your speaking voice.
  • Lungs: While cutting, an angle grinder can create smoke and other potentially hazardous fumes. Be sure to use an N-95 rated respiratory mask.
  • Hair: Tie your hair back and wear a hat so you don’t catch an ember.
  • Clothing: Do NOT wear loose or frayed clothing that can get caught in the spin and pull your fingers into rotating parts of the tool. Also be aware frayed clothing can easily catch fire from flying sparks.
  • Gloves: Gloves are a controversial topic with rotating tools. Gloves can get caught and pull your finger or hand into the moving part of the tool.  On the other hand, gloves protect your skin from heated sparks. If you decide to wear gloves, make sure they fit well and aren’t loose on your hands.

How To Use An Angle Grinder Use Proper Safety EquipmentTMB STUDIO

Step 2

Be aware of your surroundings

Do a test and be sure you know which way the sparks are going to fly — usually in the direction the wheel spins.

How To Use An Angle Grinder Be Aware Of Your SurroundingsTMB STUDIO

Step 3

Never remove the guard

The safety guard should never be considered optional. It will protect you from material flying and a shattering blade. Always keep the guard in place and adjust the placement to protect you from your material. Use the handle and don’t be tempted to take it off.

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Step 4

The right wheel for the job

  • Most wheels will give you information needed right on the blade — i.e. speed, angle of blade and what material it’s for.
  • Marry the material to blade choice. Select your wheel based on the materials you want to remove or cut — metal, masonry or wood.
  • Know the size of blade recommended for your angle grinder. Most common is 4-1/2-inches.
  • Know the recommended revolutions per minute (RPM) for your angle grinder.
  • Make sure the blade capacity is higher than the RPM of the grinder.
  • Always use a wheel that’s in good condition. Replace any that are chipped, warped or damaged.
  • When installing or replacing a cutting wheel or disc, make sure the angle grinder is NOT plugged in.

Pro tip: Wheels usually come with pictures and instructions for optimal use. Follow manufacturer’s instructions. Not all wheels work the same. Some are meant for cutting straight down, others for grinding at an angle. Ignoring these specs compromises your safety.

How To Use An Angle Grinder The Right Wheel For The JobTMB STUDIO

Step 5

Different kinds of wheels

All angle grinders work the same and come with the same basic components. Some have more power; others operate at different RPM. There are lots of wheel options for the material and job:

Cut-off wheel: This comes in different thicknesses. The thinner the cut-off wheel, the faster it will cut. Be aware a thinner disc can easily shatter, making it important to insure the wheel is in good condition.

This is used primarily to cut metal pieces like bars, tubes and small pieces of sheet metal or plates. It can also cut out welds or shorten bolts.

Grinding wheel: For metal. It’s considered an all-purpose disc for cleaning up and material removal.

Flap wheel/disc: Commonly used for finishing work, this works like a traditional grinding wheel but provides a much finer finish to your material. The disc is made of overlapping abrasive sheets called flaps, hence the name. Available in several grit options.

Just like sandpaper, the higher the grit, the smoother the finish. Depending on the grit, flap discs may be used on metal or wood. Usually it’s less aggressive than a thicker grinding wheel.

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Wire wheels: Used to remove rust from metal quickly or polish it. Wire wheels come in varying styles with different purposes. There’s a cup style and a wheel style, with various configuration of wires protruding from a circular base. They feature thick, twisted bristles, which are more abrasive for faster, easier work, or thinner, straighter bristles for finer, precision jobs.

They can be used on softer materials, but may leave scratches on the surface. Wire wheels are also an option for removing paint. They usually screw directly on to the threaded spindle.

How To Use An Angle Grinder Wire WheelsTMB STUDIO

Paint stripping wheels: Sometimes called strip discs, these are a common alternative to wire wheels for removing paint from a surface. Made of poly-fiber material, they’re less likely to scratch material. Stripping wheels are a good choice when working on more delicate materials like soft metals, wood, or fiberglass. They’re also good for removing epoxy or other residues.

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Concrete grinding or diamond wheels: For cement, stone, brick and tiles, these come in many shapes and forms. They’re good for removing concrete from a surface or polishing concrete. Made of solid materials like fiberglass or diamond, they can handle masonry, granite, marble, stone and other hard materials. There are even wheels made to cut tile and porcelain.

Discs last a long time; replace them when they begin to chip. Masonry or concrete wheels can be expensive, so be sure to use the right one for the job.

How To Use An Angle Grinder Concrete Grinding Or Diamond WheelsTMB STUDIO

Angle Grinder FAQs

Are discs for an angle grinder directional?

Some are, some aren’t; check the label to be sure. A 1-mm cutting disc for metal and diamond wheel blades can be placed on the spindle with either face up; they don’t have a direction of cut. On the other hand, some discs are meant to be used flat and sit in only one direction when secured in the spindle. Whichever blade you’re using, ensure the disc is correctly seeded on the tool so its bore is properly aligned, sitting flat and snug fitted to the spindle.

In which direction should the angle grinder spin?
In most cases, you want it spin away from you. This will force the material and sparks downward instead of upward. Being left-handed, I’m conscious of how I position the angle grinder to make sure the material spins away from my body and face. Most tools are not made for lefties, so we must adjust to make sure we’re safe.

What should you NOT cut with an angle grinder?
Hardened steel, high-strength alloys and some ceramics may require specialized cutting wheels or techniques. Additionally, materials that are highly flexible or elastic, like rubber or certain plastics and acrylics, may melt and can’t be easily cut with an angle grinder. Always do a test before proceeding.