Angle Grinder FAQ: What Is An Angle Grinder & How To Use It?

If you are unfamiliar with what an angle grinder ism or how to use one, you probably have more than a few questions you’d like answered about them.

This article is intended to answer as many of those questions as possible from buying questions like ‘best brand of angle grinder’, all the way down to ‘where and when to use an angle grinder’ so you can make the best operation and buying decisions for you.

This guide is really a Who?, What?, When?, Where?, Why?, How?, Do? and Can?, of buying and using an angle grinder.

If you are looking to buy an angle grinder, it is probably worth checking out Best Angle Grinder: Buyer’s Guide and Reviews for more information on making that decision.

Back to this article – feel free to use the table of contents below to navigate your way to specific questions and answers, or read at your own leisure:

[toc]

Angle Grinder FAQ: What Is An Angle Grinder & How To Use It?

 

Who…Angle Grinder?

 

Who makes the best angle grinder?

It is not about who makes the best angle grinder, but rather who makes the best angle grinder for you.

For example, do you want a cheap angle grinder, 4.5 inch angle grinder, variable speed angle grinder, small angle grinder, cordless angle grinder, or 7 inch angle grinder?

Some brands focus on high quality only, and their prices will be a little higher. Other brands might offer cheaper angle grinders at the expense of some longevity of the tool and less features.

You might like to read Best Angle Grinder: Buyer’s Guide and Reviews to get an idea of what brand is most suitable for the type of angle grinder you are looking for.

 

What…Angle Grinder?

 

What is an angle grinder?

An angle grinder is a power tool that is used to mainly to grind, cut and sharpen.

Angle grinders come in electric (and cordless/battery operated), air tool/pneumatic, and gas/petrol types. Although electric is the most common.

 

What is an angle grinder used for?

As mentioned above, some of the uses of an angle grinder are to grind, cut, sharpen, clean, debur, polish and sand.

Angle grinders are used on a range of materials and surfaces for cutting and grinding including but not limited to wood, sheet metal, bar metal, bolts, steel and rebar, stucco and plasterboard, tiles, bricks and mortar, concrete and stone.

Using an angle grinder can be useful to sharpen other tools such as pruning shears and lawnmower blades.

They can also be used to sand and shape wood, or to polish surfaces like stone.

Just about any trade like welders and car repair technicians can and do use them, as well as the casual DIY’er.

 

What is the best angle grinder to buy?

The best angle grinder to buy is:

1) One that does the task you want it to i.e. does it cut, grind, polish..

2) Suitable for the task i.e. 4.5 inch angle grinders are suitable for most tasks, but a 7 or 9 inch angle grinder may be required for instances where heavy metal grinding is required, just as an example.

Another example is that you may need a cordless angle grinder as opposed to an electric angle grinder due to lack of power source where you are working.

3) One that meets your objectives of price, quality and features you require.

This article can help you consider these three factors – Best Angle Grinder: Buyer’s Guide and Reviews.

 

What size angle grinder should I buy?

Size means several different things on an angle grinder:

1) Grinder/Unit Size – some angle grinders are specifically designed and constructed as a ‘small angle grinder’. These angle grinders come with a decreased width, length, depth and weight compared to regular 4.5 inch angle grinders.

2) Disc Diameter, Size and Arbor Size -Disc diameters usually come in the following sizes, with the larger disc sizes usually meaning the angle grinder itself gets bigger and heavier:

  • 4½ inch – 115mm (most common)
  • 5 inch – 125mm
  • 6 inch – 150mm
  • 7 inch – 180mm
  • 9 inch – 230mm

Arbor sizes are usually 5/8 and 7/8 inches.

If you want a lightweight grinder for a specific task, get a small angle grinder.

If you want a standard angle grinder, you generally will go with a 4.5 inch angle grinder.

Metal workers and people performing heavy duty tasks might go with the 7 inch and 9 inch angle grinders which have alot more power and Amps.

 

What are the angle grinder disc types?

You should always buy the angle grinder discs or attachments that fit your angle grinder (we don’t support one particular brand), but Bosch has a great page that lists the different sorts of angle grinder discs and attachments which will give you an overview on disc types.

 

What are angle grinder brushes?

Angle grinder brushes are usually small brush pads/blocks made of carbon, that sit within the grinding unit and protect the motor and gears from grinding debris that could get stuck of lodged in there.

Another meaning of angle grinder brushes might refer to the actual grinding cup brush attachment made of course steel wire.

 

What is an angle grinder show?

An angle grinder show can refer to two things.

The first is a burlesque type show where the performer entertains the crowd usually in a dark room, by grinding on a piece of metal attached to them by strap/s, shooting grinding sparks in different directions.

The second is an actual trade tool show, where the latest angle grinders and angle grinder accessories and technology are shown to tradesmen or the general public by the manufacturers.

 

What is an angle grinder tool?

Angle grinders are referred to as an angle grinder tool to differentiate them from the other types of grinders in other industries such as coffee grinders, herb grinders, food grinders and so on.

 

What is an angle grinder flap disc?

An angle grinder flap disc or flap wheel is an abrasive disk used for metal finishing or wood sanding (when using the sanding flap disc). Unlike the simpler flat disks, made from a circular flat sheet of a coated abrasive, a flap disc is made of multiple overlapping small pieces or ‘flaps‘, bonded to a central hub.

Some manufacturers refer to it as a Type 29 disc, with the other types being a Type 1 Cutting Disc, and a Type 27 Grinder disc.

Flap discs can be made of an aluminium zirconium grit, and be used for metal blending and grinding, and wood sanding among other things.

 

What is the best cordless angle grinder?

We identified both Makita and Bosch to have the best cordless angle grinder.

 

What is the best brand of angle grinder?

You can check out the best brand of angle grinder for your particular needs.

 

When…Angle Grinder?

 

When to use an angle grinder?

An angle grinder is intended for use in grinding when you want to grind a surface, shape a material, remove rust and grind down welds, remove paint, debur a surface or even sharpen an edge of another tool or blade.

Using an angle grinder to cut wood or metal is generally useful when a saw blade or a hacksaw won’t get the job done. Other ways to cut metal apart from using a cutoff or bandsaw, or angle grinder, can include using metal shears, tin snips or an oxy-acetylene gas cutting torch.

It should be noted that using an angle grinder produces a quick, powerful but rough/uneven cut – so, if you want a precision cut, use another power tool like a jigsaw, or table or miter saw.

 

When to change angle grinder disc?

You should know when to change an angle grinder disc in the following instances:

1) When you need to perform another task – You will need a different disc to grind than you will to cut for example. Change the disc according to the task you need to perform. If you’re unsure of the discs and their uses, check out a disc manufacturer website.

2) When the disc is worn down- It is generally recommended you use discs until they are grinded down to about 2/3 the size they started at. As the disc gets more worn, it grinds more slowly, because it stays at a constant RPM, but less disc circumference.

Other people prefer to replace or change the angle grinder disc it gets worn down to the two plates or screw/clamping nut holding it in place.

For cutting discs, when you lose the edge/it starts to get too blunt – it’s time to change the cutting disc.

3) Disc failure – pretty obvious one…if the disc breaks or fails under pressure or speed.

 

Where…Angle Grinder?

 

Where to use an angle grinder?

Angle grinders can be used in almost any environment where power cutting, grinding, sanding and polishing is required.

Metal workers and fabricators, car repairers, carpenters, along with residential DIY operators (the average person) can all use an angle grinder.

The most common electric angle grinder obviously needs a power source like a generator or powerpoint to operate.

Cordless angle grinders, gas angle grinders and air angle grinders can all be used remotely.

 

Where to rent an angle grinder?

You can rent angle grinders from a tool store or hire store – in person or online. Simply google ‘rent power tools + your country’.

For the US, Home Depot.

For UK, HSS.

For Canada, Home Depot Canada.

For Australia, Kennards or Coates.

 

Where to buy an angle grinder?

You can buy an angle grinder online via a tool store, or Amazon – you might like to check out Best Angle Grinder: Buyer’s Guide and Reviews.

Otherwise, google your local tool store if you’d prefer to check the tools out in person.

 

Why…Angle Grinder?

 

Why use an angle grinder?

There’s probably two main reasons you’d want to be using an angle grinder:

1) They have more power than a handheld tool like a hack saw

2) They are one of the most flexible power tools out there – they can cut, grind, sharpen, polish, sand and more!

 

Why variable speed angle grinder?

Variable speed angle grinders are angle grinders which have more than one operating speed.

A regular speed angle grinder has two speeds – On, and Off.

A variable speed angle grinder has multiple speeds, ranging anywhere from around 2000rpm to about 12000rpms (speeds can be anything the manufacturer chooses them to be).

When using and angle grinder, it is useful to have a variable speed feature for setting the tool to a suitable speed for the different tasks.

For example, if you are trying to shape soft wood, you can set the speed to the lowest setting. If you are trying to cut through very thick concrete, you can turn the speed up to a high setting.

 

How…Angle Grinder? 

 

How to use an angle grinder?

To use an angle grinder, and use it safely, you may choose to follow these steps and precautions:

1) Ask yourself, do I have the right angle grinder and accessories for the task/s I want to perform? e.g. if you want to cut AND grind, does your angle grinder have the ability to take cutting and grinding discs, and do you have the right discs for the job/s? If you want to cut concrete for example, you will need a diamond disc.

Make sure you have the necessary backup equipment like spare discs, spare batteries (for cordless angle grinders) etc.

It is not uncommon for tradesmen like metal workers to have several angle grinders so they don’t have to spend time changing discs and attachments.

2) Make sure your grinding or cutting area is clean and free of hazards

3) Consider angle grinder safety, which includes but is not limited to:

a) wear protective equipment – glasses/facemask, breathing mask, gloves and apron

b) ensure your cutting or grinding guard is on your angle grinder

c) Will what you’re working on produce lots of dust? Consider using a dust shroud for you angle grinder.

d) Consider securing/fastening the material you are cutting or grinding if its a piece of wood or metal for example – use c clamp or vice grip

e) Check the condition of the disc and that it is appropriate for the work – can it handle the speed, and does it need replacing?

f) The level at which sustained exposure might result in hearing loss is 90 to 95 decibels – check the decibel rating of any tool you buy and wear hearing protection if necessary.

4) Attach the appropriate grinding attachment to your grinder using the wrench or hex tool – ensure the safety lock/disc lock (usually located on the top of the grinder) is on while you do this!! Attach the side handle if you want extra stability.

5) How you use the grinder once you have the correct attachment on is up to you, but you’re now ready to turn on the grinder. Here are some tips for operating the angle grinder:

a) Keep the wheel facing away from you (having the guard on the closest side to you helps to not get hit with sparks and debris)

b) If cutting, try to mark out what you are cutting beforehand with a market for straighter cuts

c) For grinding or sharpening, secure the material, keep pressure of the grinder even, and try to grind in straight/parallel or layers lines if smoothing a surface.

 

How does an angle grinder work?

Angle grinders work by drawing their power either by electricity, batteries, petrol/gas or air.

They are made up of a unit that houses the gears and motor which is attached to a spinning shaft. The spinning shaft rotates the angle grinder attachment – a wheel/disc, brush, polishing pad, sanding discs etc.

The attachment will then mainly grind or cut the surface which they come into contact with.

 

How to use an angle grinder to cut metal?

To cut metal like nuts and bolts, iron mesh, plate metal and more with your angle grinder:

1) Attach a metal cutting wheel to your angle grinder (ensure your grinder takes cutting wheels, and you have a cutting guard). Use a cheap and standard metal cutting wheel for softer metals, or a diamond blade for more heavy duty metal

2) Secure it with a C clamp (cheap) or a vice grip (more expensive)

2) Cut the metal – expect a powerful, quick and imprecise cut (although you can mark the cut beforehand).

 

How to use an angle grinder to clean metal?

Use the above process of cutting metal, except you will want to attach a metal cup brush, or a metal wire wheel to your angle grinder (not to be confused with a grinder wheel).

 

How to use an angle grinder to cut steel?

In this instance, we are talking about cutting steel like rebar, other bars and steel bolts:

1) Attach a steel cutting wheel to your angle grinder (ensure your grinder takes cutting wheels, and you have a cutting guard). Usually and aluminium oxide wheel will be fine.

2) Secure the steel with a C clamp (cheap) or a vice grip (more expensive)

2) Cut the steel – expect a powerful, quick and imprecise cut (although you can mark the cut beforehand).

 

How to use an angle grinder to cut stucco/plaster?

Plasterboard or stucco can be cut usually in small areas and lines with a saw or sawing power tool. For large areas though you can use an angle grinder:

1) Attach a regular metal cutting wheel or diamond wheel to your angle grinder (ensure your grinder takes cutting wheels, and you have a cutting guard).

2) Mark, tape & cut the plasterboard – expect a powerful and quick cut.

 

How to use an angle grinder to cut concrete?

In this instance, we are talking about cutting concrete like part of a slab, driveway or footpath for example:

1) Attach a dry cut diamond cutting wheel to your angle grinder (not a regular cutting wheel). Consider using a higher powered 4.5 inch grinder for this task.

2) Mark out the area you want to cut.

2) Cut the concrete. Expect vibration through the grinder, and take breaks frequently so you don’t overload the grinder.

 

How to use an angle grinder safely?

Take the following precautions to use an angle grinder safely:

a) wear protective equipment – glasses/facemask, breathing mask, gloves and apron

b) ensure your cutting or grinding guard is on your angle grinder

c) Will what you’re working on produce lots of dust? Consider using a dust shroud for you angle grinder.

d) Consider securing/fastening the material you are cutting or grinding if its a piece of wood or metal for example – use a c clamp or vice grip

e) Check the condition of the disc and that it is appropriate for the work – can it handle the speed, and does it need replacing?

f) Understand there may be kickback on the grinder if there is no soft start – get a soft start grinder if necessary

g) Grinder stays running if there is no quick release switch – paddle switches can work well if you drop the grinder

h) Disc breaking – get a disc which can take the rpms and the tasks e.g. use a diamond blade for concrete, and check disc condition regularly.

i) Motor overheating – get a quality grinder and wear gloves when using for extended periods

 

How to use an angle grinder on wood?

You can use angle grinders on wood to sand, shape and cut:

1) Attach your preferred disc to the angle grinder – you can you use flap discs (with sand paper on the wheel) for sanding, an abrasive disc marked for wood use for grinding or shaping, a lancelot type disc if you want to turn your angle grinder into a mini chainsaw (not as precise cutting), or a wood cutting disc.

2) Mark out the area you want to cut. If you want to sand or shape, apply pressure evenly and move the disc across the surface in a parallel motion as opposed to straight down.

2) Cut, sand or shape the wood. Expect wood shavings so wear eye protection.

 

How to use an angle grinder to remove paint and rust?

Removing paint and rust from metal with an angle grinder is popular for fences, letterboxes, old cars and more:

1) Attach a wire wheel or wire cup brush to your angle grinder.

2) Begin removing the rust or paint – apply pressure evenly over the surface, and avoid pressing down too hard in any one spot to avoid removing too many layers.

 

How to use an angle grinder to cut tiles?

In this instance, we are talking about cutting ceramic tiles:

1) Attach a dry cut diamond cutting wheel to your angle grinder (not a regular cutting wheel). Consider using a higher powered 4.5 inch grinder for this task.

2) Mark out the area you want to cut.

2) Cut the tiles. Expect vibration through the grinder, and take breaks frequently so you don’t overload the grinder.

 

How to use an angle grinder to cut stone?

In this instance, we are talking about using an angle grinder for residential stone used for joinery and bench tops for example

1) Attach a dry cut diamond cutting wheel to your angle grinder (not a regular cutting wheel). Consider using a higher powered 4.5 inch grinder for this task.

2) Mark out the area you want to cut.

2) Cut the stone. Expect vibration through the grinder, and take breaks frequently so you don’t overload the grinder.

 

How to use an angle grinder for polishing?

In this instance, we are talking about using an angle grinder to polish stone or floorboards:

1) Attach a backing pad and wool bonnet to your angle grinder (not all angle grinder take this attachment)

2) Begin polishing. Apply pressure evenly and move the grinder in a circular motion to leave an evenly polished finish.

 

How to use an angle grinder for sanding?

Using an angle grinder to sand wood is usually for sanding very quickly and for large areas where you don’t want to use hand held sand paper:

1) Attach a flap disc or abrasive sanding disc to your angle grinder.

2) Begin sanding. Apply pressure evenly across the surface of the material you are sanding.

 

How to sharpen mower blades with angle grinder?

To sharpen mower blades or restore edges of cutting tools:

1) Clamp the blade into a vice or clamp if possible to secure it

2) Attach a regular metal grinding wheel to your angle grinder

3) Align your angle grinder with the angle of the cutting blade and move the grinder across the blade

4) If you want a finer edge, use a file

 

How to grind concrete with angle grinder?

Using an angle angle grinder to grind concrete is usually to remove marks, concrete spurs and defects, or to smooth the concrete surface

1) Attach an abrasive concrete grinding wheel or disc, or wire wheel for very fine concrete.

2) Begin grinding. Apply pressure evenly across the surface of the concrete.

 

How to cut bricks with angle grinder?

Using an angle grinder to cut bricks is useful for masonry workers (although a brick/miter/table saw is more frequently used):

1) Attach a diamond blade to your angle grinder

2) Mark the line on the brick you want to cut. If it s free brick, secure it with a vice.

3) Cut the brick. Expect brick sand debris/brick dust while you are cutting.

 

How to grind mortar with angle grinder?

Using an angle grinder to grind or cut mortar is useful for removing the mortar or simply repointing the brick joints:

1) Attach a thin diamond disc to your angle grinder (for a precise cut)

2) Wear a mask (so you don’t inhale brick dust) and make several small cuts in the mortar joint until you remove it or it is repointed. Try to keep a disc width away from the brick itself to prevent damaging it.

 

How to cut pavers with angle grinder?

It saves time cutting pavers using an angle grinder:

1) Attach a dry cut diamond cutting wheel to your angle grinder (not a regular cutting wheel). Consider using a higher powered 4.5 inch grinder for this task.

2) Mark out the area you want to cut.

2) Cut the pavers. Expect vibration through the grinder, and take breaks frequently so you don’t overload the grinder (consider wearing a mask to prevent swallowing paver dust).

 

How to change an angle grinder disc?

Changing an angle grinder disc is fairly simple:

1) Your angle grinder will come with (or you might have to purchase it separately) a changing wrench or a hex tool

2) Place the tool on the tightening nut or flange located on the inside of the disc and loosen it

3) The disc should come off once

4) As long as your angle grinder arbor and existing guard supports the new disc, place the new disc on and tighten the nut of flange back up with the disc tool

 

How to cut a straight line with an angle grinder?

You can follow these steps which work best with a freestanding piece of sheet metal, steel or wood:

1) You will need a straight edged piece of flatbar steel or metal, some clamps (C clamps or vice clamps) and a square edge tool

2) Place your flatbar on the sheet of material and use the square edge tool to make sure the flat bar is square to the opposite edge of the material – clamp the flat bar in place once its square.

3) You now have a straight edge you can trace a straight line along with a marker on the material you want to cut

4) Cut along the line with you angle grinder, having the edge of your disc being guided by the edge of the flatbar (don’t cut into the flat bar though obviously).

 

Do…Angle Grinder?

 

Do angle grinder sparks hurt?

They can if you are close enough to them. They can also harm your eyes, or even your airways if you are working with dangerous chemicals.

Wear the proper protective equipment like gloves, long sleeves, glasses and an apron.

 

Do I need a variable speed angle grinder?

If you want flexibility in the the speed and torque that your angle grinder disc has, you will need a variable speed angle grinder.

This is particularly true if you are working with softer and weaker materials, together with tougher and harder materials for cutting, grinding and so on.

 

Can…Angle Grinder?

 

Can angle grinder be used to cut wood?

Yes – with a flap disc, sanding wheel, lancelot wheel and regular wood cutting disc.

 

Can angle grinder cut concrete?

Yes – use a diamond wheel cutting disc.

 

Can angle grinder cut metal?

Yes – use a metal cutting wheel.

 

Can angle grinder be used as polisher?

Yes – use a backing pad and a wool bonnet attachment.

 

Can angle grinder be used to sharpen a blade?

Yes – use a regular metal grinding disc.

 

Can angle grinder cut steel?

Yes – use a regular metal cutting disc.

 

Can angle grinder cut tiles?

Yes – use a diamond wheel.

 

Can angle grinder cut brick?

Yes – use a diamond wheel.

 

Can you use an angle grinder as a buffer?

Yes – use the polishing attachment.

 

Can I use angle grinder to polish car?

Yes – use the polishing attachment.

 

Can I use angle grinder to sand wood?

Yes – use an abrasive sanding disc or a flap disc with sanding paper pieces.

 

Angle Grinder Resources

  1. https://tooljuice.com/best-angle-grinder-buyers-guide-reviews/
  2. https://www.boschtools.com/us/en/boschtools-ocs/metal-cutting-grinding-brushing-accessories-22076-c/
  3. https://www.reference.com/science/loud-75-decibels-9bc5167e3a880b06

Leave a Comment