Flap Discs Vs. Grinding Wheels: When To Use A Flap Disc. Grinding disc for metal


DIY users approaching projects in the metal fabrication field, where steel cutting is required, always have an initial question on what is the best abrasive product to efficiently cut through both stainless steel and mild steel. There are a few key determinants to selecting both the appropriate power tool for your project, and the most effective steel cutting abrasive for your project. For DIY users these factors depend largely on what type of material needs to be cut, the thickness of the metal that needs to be cut, and the accessibility of the metal area that needs to be cut. We aim to go through the best abrasive for the job below.

Best Power Tools to Cut Steel

Steel can be cut with a variety of power equipment, depending on the shape of the steel that needs to be cut. A bench mounted, drop saw will fit a 14” 350mm or 16” 400mm cutting blade, and this is most suitable for heavier steel work as the chop saw can cut through almost any metal with the correct cutting blade.

A bench mounted drop saw is particularly useful for cutting repetitive lengths of steel quickly and accurately. The limitation with this tool is that it will only cut at a straight 90º angle. For thin, fiddly auto work, a rotary or air tool may be your weapon of choice. These are particularly useful power tools to get into those hard to reach areas where heavier, bulkier tools cannot be manoeuvred. You can also cut metal with a hacksaw, however this is much more intensive work for something a power tool can do in a fraction of the time.

However, the most popular and versatile power tool to use to cut steel is an angle grinder, due to its size, affordability, and portability. An angle grinder can be purchased in a range of sizes to suit different sizes abrasive cutting discs. Each angle grinder will operate at a different RPM to suit the respective disc, therefore it is important not to fit an incorrect sized disc on an angle grinder. They will also have a guard that should never be removed to accommodate a wheel that is not meant for the grinder size.

An angle grinder includes a spindle washer and spindle nut that you’ll install in different configurations to accommodate thicker or thinner wheels or remove altogether when screwing wire wheels and cups onto the threaded spindle. The most popular angle grinder sizes in Australia for both professional fabricators and DIY users are 4″ 100mm and 5″ 125mm.

Choosing Profile of Cutting Wheel

There are two types of common cutting wheels to suit an angle grinder: Type 1, which is flat; and Type 27, which has a depressed centre.

Generally speaking, Type 1 wheels offer more versatility, especially when cutting profiles, corners or anything that requires the operator to cut up and over two different planes of cutting surface. Type 27 wheels, on the other hand, are ideal for getting into tight corners or overhangs. The depressed centre of a Type 27 wheel provides the extra clearance sometimes needed to get the job done. It is strongly recommend that the general DIY user purchases a flat Type 1 cutting disc which is the more popular type of wheel.

Choosing Grain and Quality in Cutting Wheels

The most popular grain used in the manufacture of abrasive cut-off wheels is aluminum oxide. This is a softer bond that results in a cut that is fast, smooth and easy-to-control.

These aluminium oxide cutting wheels can be purchased in INOX grade quality, which means the abrasive wheel contains no iron and therefore has the ability to cut both stainless steel and mild steel. If the cutting disc does not specify for use on Stainless Steel or have INOX stamped on the label, then it is most likely only suitable for mild steel cutting. As stainless steel is one of the harder types of steel to cut, a disc that cuts through stainless steel will cut through all types of metal including aluminium, sheet metal, rebar and other mild steels.

Choosing Thickness of Cutting Wheels

Cutting discs are available in different thicknesses, and the type of wheel you select depends on the type, shape and thickness of the steel that needs to be cut. For standard everyday jobs on either stainless or mild steel using an angle grinder, choose a 1mm or 1.6mm thickness in your disc.

For projects that involve thin metal such as sheet metal, choose a 1.0mm or 0.8mm thinner cutting disc. These thinner discs will sheet metal faster and as such, minimise discoloration and leave less work in the clean-up of the surface of the metal once you’re done.

When working with Aluminium, best results it is recommended to apply cutting wax or other type of saw lubricant to the cutting disc to preserve the life of the blade and avoid chipping. For heavier steel cutting jobs where you need to cut through a significant thickness of metal, select a 1.6mm or 2.5mm thickness of cutting disc. However, it is important to note that thicker wheels cut slower and generate more friction and heat through the cut — often discolouring the workpiece and requiring additional steps to finish.

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Tips on Using Cutting Wheels on an Angle Grinder

Rule number one when using an Angle Grinder is SAFETY. This means; the correct wheel for that sized grinder, appropriate safety gear ( safety gloves. face shield, safety glasses etc), let the wheel do the work – don’t push it, and pay attention to what you are doing. It is important to use even pressure and consistent motion through the cut. Let the wheel do the work and use the weight of the tool to complete the cut. Pushing too hard increases cut speed but also generates heat and friction, which ultimately reduces wheel life and can be very dangerous.

Abrasives Suppliers

A good abrasive supplier will stock a range of cutting discs for mild and stainless steel to suit the bench mounted drop saw, angle grinder and air tool. At Smith ARROW, an Australian company, we stock cutting abrasives to suit all different sizes drop / chop saws. air tools, rotary tools. roloc tools and angle grinders. We sell very high quality cutting discs for the metal fabrication market.

Smith ARROW is the only abrasives range in Australia to receive INDEPENDENT CERTIFICATION for our entire range of cutting and grinding wheels (equal to or greater than 100mm diameter) as complying with Australian Standard AS1788.1-1987 from SAI Global. As a result, Smith ARROW has been licensed by SAI Global to use their “5 Tick” Quality Certification Mark – one of the most recognisable and respected Quality Marks in the world – on the labels and packaging of all of our cutting and grinding wheels within this range under both our Smith ARROW Brand.

Along with a wide and ever increasing range of high quality industrial consumables that represent amazing value for money for our customers, Smith ARROW supply cut off wheels to suit all steel, in a range of thicknesses to suit your preferred application. View our entire cutting disc range here.

Flap Discs Vs. Grinding Wheels: When To Use A Flap Disc

Flap discs offer benefits such as fast stock removal and the ability to grind, blend, and finish with a single product, which can improve project timeline without compromising on results. In general, you’re better off using a flap disc over a grinding wheel when abrading metal and applying a smooth finish.

When using an angle grinder, choosing the right attachment for the job is critical to a successful outcome. The most common options are flap discs and grinding wheels. While they are often confused due to some overlapping characteristics, the two different abrasive products are not the same. In this blog, the team at Red Label Abrasives explains what they are, the recommended applications for each one, and when you should opt for a flap disc over a grinding wheel for your project.

What is a Flap Disc?

A flap disc is an abrasive product used to contour and shape metal. It consists of overlapping abrasive flaps glued to a backing plate and is regularly used for welding, machining, heavy-duty equipment work, and industrial maintenance. Common applications include:

  • Cleaning flash from molds and castings
  • Removing rust
  • Edge grinding
  • Deburring
  • Blending weld seams

Flap discs offer benefits such as fast stock removal and the ability to grind, blend, and finish with a single product, which can improve project timeline without compromising on results.

When Should You Use a Flap Disc?

Flap discs are the recommended choice when you’re working with metal, especially when you intend to make right angle cuts. Being flexible, these discs make it easier to achieve contours in the metal.

For grinding, apply heavy pressure and for finishing, apply light pressure. You thereby avoid the downtime caused by switching discs between tasks. Other benefits include:

  • Cooler operation, minimizing the risk of scorch or heat marks
  • Reduced vibration and fatigue for a more comfortable experience
  • Safety is improved because there are no pieces that break or fly off
  • With less gouging, the finish is better

What Are Grinding Wheels?

Grinding wheels are one of the most commonly used abrasive products. Made from thousands of tiny abrasive grains, they remove material to both shape and refine a workpiece.

Different types of grinding wheels are available, and each type serves a different purpose. Some are sharpeners and cutters, while others are polishers and smoothers.

When Should You Use a Grinding Wheel?

Grinding wheels are great for general sharpening tasks, such as restoring edges on worn-down shovels and garden tools or performing an initial grinding on lawn mower blades, shears, hatches, and axes. They can also be used for material removal, but aren’t as great for finishing work due to their tendency to gouge surfaces.

When To Use a Flap Disc Over A Grinding Wheel

In general, you’re better off using a flap disc when abrading metal and applying a smoother finish. Although they’ve long been used with high-speed angle grinders, advances in both design and materials have brought flap discs to the point where they can carry out grinding, blending, and finishing jobs much more quickly and with less noise than grinding wheels- layered flaps constantly expose new grain and act as a cushion, resulting in less noise and vibration.

  • Users have better control over flap discs, making damage (and rework to repair it) much less likely.
  • Operators tend to find flap discs more comfortable to use, so they’re a recommended option for longer grinding jobs.
  • Since flap discs don’t gouge the workpiece as fast as grinding wheels do, a less-skilled operator can use them more efficiently without damaging the work piece

Grinding wheels can play an important role in your project, particularly during material removal, but when you’re working with metal and need a tool that can achieve results during each stage of the project, flap discs may be your best and most efficient option.

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Questions? Speak With An Abrasive Specialist

At Red Label Abrasives. we are a leading and trusted provider of specialty abrasive products, including sanding belts. discs. rolls. and flap discs. Whether you need the right abrasive for your application or advice on how to get the most out of your product, our technicians are here to help. For more information or help in placing an order, please call 844-824-1956 or fill out our contact form.

Bosch Mild Steel Grinding Disc 4 inch 2608600017

Specification: A 24 S BF Diameter: 100 mm (4″) Bore diameter: 16.0 mm Thickness: 6.0 mm Product type: Grinding disc Packaging: 25 pcs / box

Authorized Seller


Specification: A 24 S BF Diameter: 100 mm (4″) Bore diameter: 16.0 mm Thickness: 6.0 mm Product type: Grinding disc Packaging: 25 pcs / box


Bosch Power Tools Accessories. Bosch Mild Steel Grinding Disc 4 inch

Grinding disc for mild steel

Expert for Metal Grinding Discs

For an impressive long lifetime and maximum safety on metalAluminium oxide abrasive grain, functional fillers, additives with phenol resin bond matrix are suited for metal applicationsPrecision-manufactured fiberglass fabric for especially high disc stability and maximum work safety

The expert for metal grinding disc delivers an impressively long lifetime on metal with maximum safety. Its premium aluminium oxide abrasive grain, selected functional fillers and additives in a modern phenol resin bond matrix are particularly suited for metal applications. Furthermore, its precision-manufactured fiberglass fabric ensures especially high disc stability and maximum work safety. It is intended for grinding metal. It is suitable for use with hand-held angle grinders.

Types of Angle Grinder Discs Their Uses

Let’s check out the different types of angle grinder discs and their uses.

What is an Angle Grinder Disc?

First things first—let’s go over the basics. An angle grinder disc is any disc designed to fit in an angle grinder and rotates at high speed to perform cutting and polishing operations. The angle grinder disc or wheel spins at anywhere from around 2,800 rpm to 12,000 rpm, depending on the brand and model of the tool and the settings you select.

Just by switching different discs in and out of the tool, you can use your angle grinder for a variety of applications. You can cut, grind, polish, carve, and more.

over, you can work on a wide range of materials such as metal, stone, mortar, brick, or wood.

Angle Grinder Disc Types

Now that you know what an angle grinder disc is, let’s check out some of the most common types of discs you can use and what you can do with them.

Large and small versions of these discs are available to suit the size of your angle grinder. For general purposes, consider a larger disc. For detailed work, consider a smaller disc.

Grinding Discs

It makes sense to talk first about grinding discs, also called “grit discs.” These are the discs you need if you want to grind metal or stone. Each disc features an abrasive compound consisting of grains and a bonding agent. You can choose a higher or lower grit depending on how fine or coarse you want the abrasive grains to be.

You may want to start with a low, coarse grit to speed through the beginning of a task, and then switch to a high grit for a smoother finish.

Cut-off Discs

Next, we have cut-off discs, also known as parting wheels. Choose this type of slim, tapered wheel if you want to cut metal stock. You will find variations in thickness for cut-off discs. There are tradeoffs either way. The thinner the disc, the more easily it can slice into metal. But thin abrasive discs are brittle and more prone to breakage. The thicker the disc is, the sturdier it is, and the less likely it is to warp or fracture while you are using it.

So, you will need to weigh those pros and cons when choosing your cut-off discs. In either case, however, try not to push too hard or too fast into the metal. Doing that only makes it more likely you will damage the work and shatter the disc you are using.

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Diamond Cutting Discs

If you are working with masonry or stones, a regular grit disc or cut-off disc won’t cut. You will need a diamond cutting disc which is a superior alternative. As the name implies, diamonds grits are embedded into the edges of a steel disc.

As diamond rates a 10 on the Mohs hardness scale, it makes for efficient cutting of concrete, tiles, stones, etc. It also offers superb durability.

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So, with a diamond disc, you can work more quickly and easily, even on harder metals. It will cost you more to purchase diamond discs, but they should outlast others, making them more cost-effective in the long run than they may initially appear.

Flap Discs

A flap disc is probably the best option when you need to do some sanding with an angle grinder.

This type of disc uses abrasive (usually Aluminum Oxide) that is similar to a grit disc, but a whole lot finer. The main difference here is that instead of a single flat piece, the flap disc is made of multiple layers of overlapping abrasive sheets called flaps. Sometimes these are referred to as flap wheels, although that name is more appropriate for a radial flap wheel that you use on a drill or rotary tool.

Flap Disc Uses

With a flap disc, you can remove minor imperfections from a surface, remove rust, and polish the surface. Also, if there are fine grinding tasks that you cannot tackle using a regular grit disc, a flap disc may be appropriate. These types of angle grinder discs are often used in autobody shops, metalworking, and fabrication industries. Worried about a flap disc overheating? You can try a ceramic sanding disc as an alternative.

Wire Wheels

One of the most distinctive-looking types of wheels you can get for your angle grinder is a wire wheel. You can use a wire wheel to remove paint or rust from metal.

You also can polish hard metal with a wire wheel—but keep in mind that on softer materials, using a wire wheel is more likely to lead to scratches than a smooth finish. Instead of featuring a cutting or grinding disc, this wheel includes clusters of bristles protruding in a radial formation. These bristles may be slender and straight, or they could be thick and twisted.

The type of wire disc you should get depends on the application you have in mind. The thick, twisted bristles are kind of like coarse grit on a grinder disc. Choose them for tasks that require more speed than precision. Then, switch to straight, fine bristles for work that requires more exactness.


You should always wear safety goggles when you are working with your angle grinder. But it is extra important with a wire wheel, as wires sometimes snap off. That is about the last thing you want flying into your eye. I have seen a lot of novice users ignoring the basic safety practices when with a grinder. I wrote an entire guide on angle grinder safety since this is really important.

Paint Stripping Discs

A wire wheel is not your only option to remove paint. An alternative wheel to consider is a paint stripping disc.

If you are working on a material like wood, fiberglass, or soft metal that you could end up scuffing with a regular wire wheel, a paint stripper may be more suitable.

Instead of wire bristles, a paint stripper wheel features poly-fiber material. It removes paint with efficiency, but should not scratch or scuff the underlying surface. You also can use it to remove epoxy or other residues.

Polishing Pads

You are probably wondering by this point whether there is a type of disc designed with the specific purpose of polishing in mind. Actually, what you are looking for is a polishing pad, which is also called a “buffing pad.”

A variety of different types of polishing pads are on the market. You will need to choose a material that is right for the surface you are working on. For fine surfaces such as polishing your car, get a buffing wheel made of wool.

It is important to take it slow when you are polishing. If you select too high a speed, you will probably end up damaging your surface. Bigger angle grinders are more likely to offer you speeds that are suitable for the job.

Concrete Grinding Wheels

With the right discs, your angle grinder can not only handle metal but can even grind or polish concrete.

There are assorted shapes of concrete grinding wheels and various grit materials. You can find wheels with silicon carbide grain or diamond grit. The diamond cup wheel is the most widely used type since it can be used on a variety of materials and are durable.

Along with hard abrasive materials, these wheels are made of sturdy materials through and through like durable fiberglass. Such materials not only preserve the life of the wheel but also help it push through concrete. Besides grinding concrete with these types of discs, you can also use them to grind granite, stone, marble, masonry, and similar materials.

Although a concrete grinding wheel can offer great longevity, these tough discs eventually wear down. An old disc becomes increasingly likely to chip during use.

Wood Cutting Discs

A couple of times now, we have mentioned grinding or cutting wood using an angle grinder. But as you already know, quite a few types of discs are only suitable for harder materials. If you attempt to use them to cut or carve wood, you might end up damaging your project.

So, is there such a thing as a wood cutting disc? The answer to that question is “yes.”

Woodcutting discs typically feature a toothed, circular blade. You will notice the tips are often tungsten carbide. The reason manufacturers use carbide tips for wood cutting discs is because carbide is incredibly hard. In fact, if you need to sharpen carbide tips, you will require diamond to get the job done.

Because carbide teeth are so hard, they can make clean cuts through both softwood and hardwood. Not only that, but you can get a lot of use out of them before you need to sharpen or replace them.

What types of wood can wood cutting discs handle? You should have no problem slicing a quality disc through pine, cherry, walnut, oak, mahogany, maple, or any other wood you can name.

Wood Carving Discs

If you want to bring carving, shaping, and grinding into your woodworking, you may need to go beyond wood cutting discs to purchase wood carving discs as well.

These discs also usually include carbide teeth. But instead of a flat disc, a wood carving disc has more of a donut shape to it. The teeth are not located around the edges. Instead, they cover the entire surface of the wheel. Typically, they number in the hundreds.

With this shape, this type of disc is especially ideal for creating a concave surface—say, for example, if you are carving out the interior of a wooden bowl.

Keep in mind that working on wood is a bit different from working on metal or concrete. Those materials are typically homogenous. Wood, on the other hand, has natural contours and knots. When working with a wood carving or cutting disc, you must take care not to let your tool catch on irregular features like these. Some wheels are more prone to this than others.

  • What is an Angle Grinder Disc?
  • 10 Angle Grinder Disc Types
  • 1. Grinding Discs
  • 2. Cut-off Discs
  • 3. Diamond Cutting Discs
  • 4. Flap Discs
  • 5. Wire Wheels
  • 6. Paint Stripping Discs
  • 7. Polishing Pads
  • 8. Concrete Grinding Wheels
  • 9. Wood Cutting Discs
  • 10. Wood Carving Discs
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