How to Use an Angle Grinder

Angle grinders are incredibly versatile tools that can be used for a variety of jobs whether you’re a DIY enthusiast or just have a few jobs in mind to improve your home.

Angle grinders are incredibly versatile tools that can be used for a variety of jobs whether you’re a DIY enthusiast or just have a few jobs in mind to improve your home. They can be used to cut masonry, ceramic, metal, and even concrete, as well as for cleaning metal and sand, cutting out mortar and sharpening tools.

Using an Angle Grinder Safely

Angle grinders can be incredibly dangerous if used improperly, and even when used correctly accidents can happen, so make sure you take every precaution seriously. Never operate the tool when tired and if you’re working outside, keep an eye on the weather as rain may cause your grinder to give you an electric shock and cause you to hurt yourself.

When using angle grinders, safety is hugely important. Every time you use it, you should make sure that the handle is firmly attached and that the hand guard is angled securely to deflect sparks and debris towards the ground. Always work so that the grinder spins away from you and keep workpieces properly secured with clamps or a vice when working on them.

Safety Gear for Using an Angle Grinder

When working with an angle grinder you should wear protective gear to make sure you stay safe. You should be wearing:

  1. Protective goggles
  2. Dust mask
  3. Work gloves
  4. Work boots

You shouldn’t be wearing any loose-fitting clothing, jewellery or earphones as they could catch in the grinder, and you should keep long hair tied up under a cap.

Angle Grinder Workspace Safety

Make sure your workspace is free from clutter, keep your power cables out of the way, and make sure there is good lighting. The last thing you want to do when using an angle grinder is trip up. You should also make sure there is adequate ventilation as grinders will create a lot of dust and metal particles that could harm your lungs. Also, remove any flammable materials from your workspace as angle grinders throw sparks when grinding. Keep a fire extinguisher nearby, just in case.

Angle Grinder Disc Safety

A disc shattering when in use can send pieces flying at frightening speeds which can cause severe injury. Never use a cutting disc for grinding as they are not designed to withstand the same pressure and could shatter. You should also never use a grinding disc for cutting for similar reasons.

Never use discs at greater speeds than their max RPM, for example never use a worn down 9-inch disc on a 4.5-inch grinder. You also shouldn’t use a disc after its use-by-date as aging and moisture can weaken them – store discs in a cool dry place to keep them in good condition.

When using a new disc for the first time, make sure you have unplugged or removed the battery from your grinder before changing discs. Then run the new disc in your grinder for 30 seconds in a safe area before using it to ensure it isn’t defective.

Angle Grinder Safety Checklist

When you’re about to start using your angle grinder, follow this quick checklist to make sure it is ready to use safely before beginning:

  • Make sure the handle is secure
  • Check the guard is adjusted to the correct angle
  • Ensure ventilation slots are clear
  • Check the flex and plug for any damage
  • Make sure you are wearing the correct gear
  • Check that any flammable liquids are safely stored away

Using an Angle Grinder

As they are so versatile, angle grinders can be used in hugely different ways depending on the job you are doing. You must make sure though that you have the right disc or attachment for the job as different discs have different strengths and tolerances, and therefore can break violently.

How to Clean Metal with an Angle Grinder

Use a fibre disc to remove light rust and burrs from metal, or use a wire wheel or wire brush to clean off paint or heavy rust. Wire wheels are a great choice for getting into crevices and tight areas.

First, make sure that the item you’re working on is secure and then bring the grinder up to speed. You should always work so that the disc spins away from, and not into, sharp or rough edges for a good finish. You should work away from edges in general to avoid kick-back, but this is especially important for sharp or rough edges.

How to Cut Metal with an Angle Grinder

For this job, you should use the aptly named cut-off disc. First, firmly secure the metal with a clamp then allow your angle grinder to reach a high speed. Drop the grinder through the metal allowing the tool to do most of the work for you, applying only gentle pressure.

When cutting long lengths of metal, you should set up supports at both ends of the material and on either side of the cut so that it remains supported even after it is cut. This prevents it from falling inward which can damage your angle grinder.

How to Cut Masonry and Ceramic with an Angle Grinder

You should cut masonry and ceramic with a diamond blade disc. Tiles can be difficult as they are brittle so precision is key. First, make an outline on both the front and back of the tile as accurately as possible. The more accurate you are during this part, the better the finish you will end up with.

Clamp the tile to your workbench and score carefully along your outline on the front face of the tile, cutting about 1/8th of the way through the tile. Flip the tile over and clamp it back down to your workbench. Cut through the outline you made on the reverse of the tile, cutting slightly past the lines so your cut remains crisp on the tile’s face.

How to Cut Out Mortar with an Angle Grinder

Cutting out mortar can be a difficult job that an angle grinder can make so much easier. Use a diamond tuckpointing disc for this and clear the mortar out by making two or three cuts in the same direction - about half an inch deep.

Be careful to make sure you stay a couple of millimetres away from bricks to avoid any possibility of damage.

How to Sharpen Tools with an Angle Grinder

Quickly sharpen your tools using a grinding disc on your angle grinder. This is great for maintaining hoes, shovels and ice scrapers and for a first grinding of axes or lawn-mower blades.

Firmly clamp the blade you’re looking to sharpen at your workbench, then align the disc with the cutting edge and move along the edge with only very light pressure. Move the grinder from the handle to tip in a steady movement – do not move back and forth.

This can create a lot of heat so you should keep water and a sponge nearby to cool the blade between strokes.

How to use an Angle Grinder for Woodworking

With an angle grinder, you can carve, shape and sand using only one tool which makes it great for woodworking. Be aware though that angle grinders will remove large amounts of wood very quickly so you should test it out before using it on your project.

Use sanding discs to sand quickly, and abrasive carving discs to shape wood. There are also specially designed carving wheels for woodworking that will easily cut into wood and can be used to great effect in carving.

What Angle Grinder Do I Need?

Choosing the correct angle grinder for your needs is crucial as if you’re not careful you could end up with a machine that is too big, too powerful – or worse – not powerful enough.

What Type of Angle Grinder Do I Need?

For most home DIY jobs an angle grinder that holds discs between 4 and 4.5 inches will work very well. Smaller grinders can actually be more powerful as they are able to spin at much higher speeds – although constantly working at the highest speed setting may cause your disc to fail.

The larger the disc, the faster you can work on big jobs and the deeper cuts you can make. However, the machine will also be heavier and more difficult to control. 7-inch grinders are professional level and require both hands to use while any bigger than that can be extremely dangerous – in fact 9-inch grinders are often banned in industrial workshops for being too dangerous.

Electric or Corded Angle Grinders

Corded angle grinders are one of the most common types out there. Powerful and compact, they’re a good option for a first angle grinder.

However, as they require a cord to run they can be limiting if you want to work in a wide range of places or difficult positions. You also should be aware of the cord at all times when working with the grinder as you could easily cut through it if it gets in front of your tool.

You can find a huge range of sizes and powers for corded electric angle grinders. For more power, look for a version with a higher voltage.

Battery Angle Grinders

Battery-powered angle grinders are a great choice for a mobile tool that you can use easily without having to worry about a cord or power supply. The downside with battery-powered models is that if you’re working on a big task your battery could run down and force you to stop before you’re finished.

Battery-powered tools also tend to be smaller and less powerful than corded options. If this style works for you and you need a little more power, choose one with higher Amps.

Pneumatic Angle Grinders

Pneumatic angle grinders can be very powerful and compact, allowing you to get through your work quickly and efficiently. You will also need to buy an air compressor to run these tools, but if you already have one for your other tools then these grinders are a fantastic choice.

You should keep an eye on your discs with a pneumatic grinder as they tend to wear through them a little faster than electric versions.

Petrol Angle Grinders

Petrol angle grinders are the industrial, cordless choice. Featuring all the benefits of battery power without the need to recharge and with the power of a pneumatic grinder, petrol angle grinders are fantastic if you need something for heavy-duty use.

They do tend to be larger and heavier, making them unsuitable for small jobs and they also require extra precautions as you are using flammable liquids.

Now that you’re an angle grinder expert, check out our other helpful how-to’s to learn even more skills like how to use a power drill.