Flap Wheel – Ultimate FAQs Guide

Rubbing can make a workpiece refined and polished. An abrasive material like a mineral is usually used to rub an uneven surface.

Flap wheels are a perfect example of abrasive tools used to give your workpiece a refined and finished look.

In this write-up, you will find all the necessary information regarding the flap wheel’s specifications, types, sizes, and applications.

Let’s get started!

What Is a Flap Wheel?

Flap wheels are abrasive tools to smoothen a surface. These fast rotary tools are great for removing light material and give a finished look.

A robust and flexible cloth is embedded with abrasive grit. The coated abrasive flaps are attached around a tool axis. The adjustable flaps are ideal for contouring any surface conveniently.

The aggressive coated abrasive on the flaps help to remove high stock from variable metals and materials. You can use your flap wheels in multiple rotary tools.

Grinding and finishing hard-to-access areas, like inside pipes and tubes, were never so easy before the flap wheels. Syndent Carbide burrs can also finish such kind of jobs.

Syndent’s flap wheels are available in variable sizes, abrasives, grits, diameters, and widths. A wide range of industries benefits from the flap wheels.

Flap Wheels

How Many Types of Flap Wheels Are There?

Regarding mounting, there are two types of flap wheels:

  • Mounted flap wheels
  • Unmounted flap wheels

If we classify flap wheels concerning their flaps, there are mainly three types:

  • Coated flap wheels
  • Combination flap wheels
  • Non-woven flap wheels

Coated Flap Wheels

Syndent’s coated flap wheels are standard sandpaper flap wheels. These are ideal for heavy and light material removal, for example, weld removal, deburring, and blending. It provides you a consistent cut rate and uniform grain finish.

You can conveniently use these wheels on metals, stainless steel, and aluminum—the grits on the coated flap wheel range from 40 – 400P.

Combination Flap Wheels

As the name suggests, these flap wheels consist of a combination of sandpaper and non-woven abrasive flaps.

As compared to coated flap wheels, these are less aggressive on metals. It is ideal for delicate blending and finishing. It helps in providing you a brushed finish.

Flap Wheel

Non-Woven Flap Wheels

It is an ideal flap wheel for cleaning and a light satin finish. With the fine grits, your non-woven flap wheel provides you a finished result on stainless steel.

What Is the Difference Between Mounted and Unmounted Flap Wheels?

Syndent manufactures two types of flap wheels depending on their mounting techniques.

Mounted Flap Wheels

One type is mounted flap wheels. In this type, the abrasive flaps are joined with a resin adhesive to a central hub.

A shaft is attached to the center. You can use mounted flap wheels conveniently by screwing the collet tightly into any suitable rotary tool, like drills, grinders, or flexible shafts.

The standard shank length of mounted flap wheels is 40mm.

Unmounted Flap Wheels

Syndent’s unmounted flap wheels don’t have shafts attached to them. These flap wheels can be used in angle grinders or bench grinders.

Flap Wheel

How to Use a Flap Wheel?

Whether you are using a mounted or unmounted flap wheel, you need to know specific techniques to give you better results. These are:

  • Ensure that you start your flap wheel first before the wheel comes in contact with the workpiece.
  • It is recommended to move your flap wheel in a back and forth position.
  • Try to keep your flap wheel moving. Grinding on one position for long may result in uneven marks and more material removal than needed.
  • Choose the appropriate flap wheel size according to your workpiece.
  • Applying more pressure on the flap wheel will result in quick material removal, while light pressure will result in a smoother finish.
  • Syndent recommends you to use your mounted flap wheel at 15 – 20m/s. It is the ideal cutting speed for your flap wheel.
  • The ideal cutting speed for your unmounted flap wheels is 15 – 30m/s.
  • The recommended cutting speed of an unmounted flap wheel, when used with angle grinders, ranges from 40 – 50m/s.
  • It would be best if you use grinding oil according to your material. It increases your tool’s life and performance.
  • You can attain the best results when the edge of your flap wheel is flat against the workplace.

Flap Wheel

What Are the Uses of a Flap Wheel?

Syndent’s flap wheel is appropriate for multiple purposes. Like:


Grinding an uneven surface has never been so easy. Syndent’s flap wheel has made it convenient for you to remove the unwanted chunks in no time.

You can use variable grit size to increase the stock removal rate. Coarse grit is suitable for aggressive grinding. On the other hand, fine grit is used for giving a fine surface finish.

Machining hard-to-reach and small areas

Mounted flap wheels are ideal for working in smaller areas. You can quickly treat Hard-to-reach spaces like the inner side of the pipes and tubes with mounted flap wheels.

Machining of light and non-ferrous metals

Flexible abrasive flaps help you to grind and deburr light and non-ferrous metals. You can maintain low pressure to attain the desired results.

Flap Wheel


Smoothening the rough edges without damaging the corners can be attained with the help of Syndent’s mounted flap wheels.

For example, you can quickly deburr a carved wooden block without damaging the minor engraved details.

Stock removal

Flap wheels are available with variable grit sizes. By grit size, we mean the number of abrasive particles on the flap.

For aggressive stock removal, you can use a small grit size called coarse grit.


Flap wheels are ideal for blending the surfaces. For example, you can mix a welding point very neatly with the help of your mounted flap wheel.


Flap wheels are available in variable grit numbers. You can select coarse grit flap wheels for stock removal.

After that, use a more significant number grit wheel to smoothen the surface. It is called the pre-finishing stage.

Finishing and Conditioning

Once your metal surface is pre-finished, you can acquire a finely finished surface with the help of large grit size flap wheels, called fine grit.

Polishing and Depolishing

The aluminum oxide flap wheels can also work as buffing wheels and polishing wheels on non-ferrous metals.

You can rub the polishing compounds or polishing soaps on the buffing wheel to give your metal surface a fine finish.

Similarly, flap wheel can effortlessly depolish a surface. It removes the existing polish and gives a smooth finish to the surface.

Cleaning and De-rusting

Fine grit flap wheels are an ideal solution to remove rust from metals. They can conveniently remove paints from metal surfaces.

After removing rust and cleaning the paint, you can get a fine smooth, and finished metal to polish or paint again.

Flap Wheels

Which Industries Benefit from the Flap Wheels?

The versatility of flap wheels benefits a wide range of industries in many ways. The primary industries that use mounted and unmounted flap wheels are:

  • Mold construction
  • Apparatus engineering
  • Construction
  • Repairing and maintenance tasks
  • Robotics
  • Assembly shop operations (angle grinders with unmounted flap wheels)
  • Metal fabrication
  • Tank industry
  • Assembling industry
  • Aerospace
  • Automotive
  • Industrial
  • Marine
  • Paint
  • Plumbing
  • Welding
  • Woodworking

Flap Wheel

Are Flap Wheels Available in Variable Sizes?

Yes, definitely!

Syndent manufactures a wide range of mounted and unmounted flap wheels. They are available in variable sizes, diameters, and grit numbers. Let’s have a look:

Mounted Flap Wheels

Here are few standard sizes of mounted flap wheels. The sizes are mentioned in the pattern of:

Wheel Diameter x Flap Length

  • 10 x 10 mm
  • 15 x 15mm
  • 30 x 5mm
  • 30 x 10mm
  • 50 x 30mm
  • 30 x 20mm
  • 80 x 50mm

The diameter of the mounted flap wheel ranges from 5/8 – 3 inches.

Shank Sizes

The shank of mounted flap wheels is available in two standard sizes:

Shank Diameter x Length

  • 3 x 40mm
  • 6 x 40mm

The ¼ inch shank or ¼-20 threaded stem is helpful in quick changeovers.

Flap Wheel

Unmounted Flap Wheels

Unmounted flap wheels are available in variable sizes. Mentioned below are few standard sizes:

Wheel Diameter x Flap Length

  • 100 x 30mm
  • 115 x 20mm
  • 125 x 20mm
  • 150 x 50mm
  • 200 x 30mm
  • 250 x 50mm

The diameter of the unmounted flap wheel ranges from 3 – 9 inches.

Center Hole Diameter of Unmounted Flap Wheels

Unmounted flap wheels are available with two standard center holes in diameter. These are:

  • 4mm
  • 44mm

Grit Sizes

Syndent manufactures variable-sized grits for coarse and fine machining. The sizes available for mounted and unmounted flap wheels are:

  • The grit number of mounted flap wheels ranges from P40 – P400.
  • In unmounted flap wheels, the grit number varies from P40 – P320.

Flap Wheel

What Are the Advantages of a Flap Wheel?

Flap wheels are beneficial for you in numerous ways. Such as:

  • Syndent’s flap wheels are highly flexible. The flexibility allows you to rub any surface without damaging the particular space’s cuts, corners, and shapes.
  • The aggressive coated abrasive on the flaps allow you to remove high stock in no time. It has got a fast cutting rate.
  • You can attain a smooth finish as Syndent’s flap wheels are capable of removing carrier material uniformly.
  • Your flap wheel’s flat cast core construction facilitates you to work closely on edges and in corners.
  • You can conveniently attain a balanced grinding result at a high rotating speed.
  • Syndent values your investments and provides you cost-effective flap wheels.
  • Another advantage of the flap wheel is that you can use it in any weather condition and environment. It is heat and water-resistant.
  • The professional-grade flap wheels allow you to attain perfect results.
  • Flap wheels can conveniently fit in angle grinders. It is beneficial for facilities where no straight grinders are available. In an angle grinder, you can use unmounted flap wheels.
  • You don’t need a flange to attach/adjust the flap wheel.
  • It is ideal to use in small and difficult-to-reach spaces.
  • Compared to the sanding band, flap wheels provide you a nice finished surface without quickly penetrating the material.
  • You can work freely without the fear of catching fire or heat marks because the flaps allow you to perform your work a little cooler.
  • You can put variable pressure on your flap wheel to get desired coarser and smoother finish.
  • Flap wheels give your work smoother with less vibrating fitting.

Flap Wheels

On What Materials Can I Use My Flap Wheel?

Variable abrasives used on flap wheels are suitable for different metals and materials. So, you can use your flap wheel on:

  • Stainless steel
  • Aluminum
  • Wood
  • Copper
  • Bronze
  • Steel
  • Ferrous metals
  • Fiberglass
  • Non-ferrous metals
  • Paint
  • Plastics
  • Chipboard
  • Plexiglass
  • Silver
  • Gold
  • PVC
  • Rubber

Flap Wheel

What Is the Difference Between a Flap Wheel and a Flap Disc?

Not to mix the two flapped rotary tools – flap wheels and flap discs. Both are used in multiple surfaces for grinding, deburring, finishing, polishing, and shaping.

Both of these tools are available in variable sizes and abrasive coatings. However, there are specific differences between the two. Like:

  • Flap discs are used to shape metal, whereas flap wheels are designed specifically to machine hard-to-reach areas.
  • In flap discs, the overlapped abrasive cloth flaps are glued to a strong plate. The plate provides rigidity and stability to the flaps during grinding and finishing.
  • On the other hand, the flap wheels are made with strips of abrasive embedded cloth. These flaps are joined together by a resin core around a hub.
  • Flap wheels are available with and without shafts. In contrast, flap discs are only available without shafts.
  • Flap discs are most commonly used for heavy stock removal and shaping a surface. On the other hand, flap wheels with fine grits are used for finishing and polishing.

Flap Wheel

What Is the Cutting Speed of a Flap Wheel?

The cutting speed of Syndent’s flap wheel ranges from 15 – 40m/s. The maximum cutting speed you can work on is 40m/s.

However, Syndent recommends you work on a speed ranging from 15 – 20m/s for mounted flap wheels, and for unmounted flap wheels, it varies between 15 – 30m/s.

Rotational speed varies according to the size of your flap wheel. Smaller diameters mean high rotational speed and vice versa.

The cutting speed for some flap wheels is mentioned below:

Mounted Flap Wheels

Mounted flap wheel with a diameter:

  • 10mm works on 25,700 – 70,700 RPM
  • 20mm works on 15,000 – 40,000RPM
  • 30mm works on 9,500 – 25,000RPM
  • 50mm works on 5,700 – 15,000RPM
  • 80mm works on 35003 – 9,700RPM

Unmounted Flap Wheels

Unmounted flap wheels with a diameter:

  • 100mm works on 2,900 – 9,600RPM
  • 150mm works on 1900 – 6200RPM
  • 200mm works on 1,450 – 4,800RPM
  • 250mm works on 1,100 – 4,300RPM

Note: The speed ranges shown here are the maximum speed ranges. Recommended speed ranges may differ on the upper limit.

Flap Wheel

Which Tools Are Recommended As Flap Wheel Drivers?

Syndent’s flap wheels are convenient to use as you can mount them on any rotary tool to get the desired results.

Some tolls that can work as flap wheel drivers are:

  • Flexible shafts
  • Electric powered grinders
  • Air powered straight grinders
  • Grinding blocks (unmounted flap wheels)
  • Die grinders
  • Right angle die grinders
  • Bench grinders
  • Pedestal grinders
  • Power drills

Note: The estimated power output for the tool drivers ranges from 1000 – 1500watts.

Flap Wheel

What Factors Influence the Work Result of a Flap Wheel?

It would be best if you considered specific factors while working with your flap wheels. Some key points may affect the results of your work. Like:

  • To reduce the tool wear and thermal load, you must consider three things:
    • Reduction of the contact pressure (you must not apply too much pressure on the workpiece with your flap wheel)
    • Reduction of the peripheral speed (always work within the recommended peripheral speed)
    • Addition of grinding oil (grinding oil makes it convenient for you and the flap wheel to work on a surface. It increase the tool’s life and efficiency)
  • If you want to increase the stock removal rate, you must use a coarser grit size rather than increasing the pressure. An increase in contact pressure may result in tool wear and thermal load.
  • To attain a more refined surface, you must increase the speed of your flap wheel.
  • Increased contact pressure may result in a rough working surface. Softer materials get more uneven with increased pressure as compared to hard metals.
  • Always use an appropriate-sized flap wheel according to your workpiece. Smaller wheels for larger spaces may waste time, and larger wheels for small surfaces may affect the results.

Flap Wheel

What Safety Measures Shall I Take While Using a Flap Wheel?

Whenever it comes to working with a rotary tool, you must not forget to take precautionary measures. Here are specific safety measures you must take before you start your machining.

  • Syndent recommends you to always work in the permitted rotational speed.
  • Save your hands – wear gloves
  • Prevent your eyes from flying metal chunk by wearing goggles.
  • Ear defenders are a must wear to protect your ears from the chattering sound of grinding.
  • Wear a face shield to protect your face.
  • Wear a fire-retardant outfit.
  • Ensure your mounted flap wheel is securely screwed.
  • The clamping depth of the mounted flap wheel must be more than 15mm.
  • Unmounted flap wheels must be used with appropriate clamping flanges.
  • You must work by remaining within the permitted rotational speed.
  • The permitted peripheral speed for unmounted flap wheels is 50m/s.
  • Flap wheels for angle grinders can work on 80m/s.
  • Ensure you work space is free from any flammable object.
  • Always unplug the power supply while changing the flap wheel on your rotary tool.
  • Keep the working space neat and clean. It must be free of any oil and water spills.

Flap Wheel

What Are the Various Features of a Flap Wheel?

The various features a flap wheel must possess are:

  • The resin bonding prevents the flaps from detaching from the core of the wheel.
  • Heavyweight cloth backing makes your flap wheels durable.
  • Fine and coarse grits allow you to work efficiently.
  • Variable abrasive coatings are suitable for different applications.
  • Varying sizes and diameters will enable you to work on any surface.
  • Heat-resistant and water-proof nature increase the number of applications.

What Factors Shall I Consider While Buying a Flap Wheel?

First of all, you need to know for what purpose you are buying a flap wheel. The goal will lead you to think about further specifications you must consider while buying. For example:

  • Choose an appropriate width and diameter according to your workpiece.
  • Select the best suitable abrasive to attain the desired results.
  • You must go for coarse grits and harsh abrasives if you want stock removal and aggressive cutting.
  • Fine grits, fleece cloth, and buffing wheels are the best options to attain fine finishes.
  • You can choose between the mounted and unmounted flap wheels according to the rotary tool available at your facility.
  • Always buy your rotary tools from an authentic and reliable manufacturing company.
  • It would be best to buy from the flap wheel manufacturers and suppliers who offer you a good warranty.
  • Certified flap wheels are more durable and dependable.

Flap Wheels

Can I Get a Customized Flap Wheel?

Yes, why not?

Syndent is always here to serve you to the utmost. You can get customized sizes and abrasives with your desired grit numbers.

You can get variable-sized shank lengths and threaded shanks. On your demand, Syndent can provide you with variable shank lengths.

You can also get a customized flap wheelset. The flap wheelset may contain standard and most commonly used flap wheels.

Or, you can get customized flap wheel combinations according to your demands.

Standard sets contain variable-sized flap wheels with a 6mm shank diameter and aluminum oxide abrasive.

For your convenience, Syndent can facilitate you with customized flap wheel diameters, width, shank diameter, abrasives, and grit numbers.

Just give us your demands and leave the rest on Syndent’s specialized team of engineers.

Flap Wheels

What Is the Life Span of a Flap Wheel?

Syndent flap wheels possess a long life span. However, certain factors play their part in determining the duration of a flap wheel. These are:

  • Coarse grit flap wheels last longer than fine grit wheels.
  • Applying unnecessary pressure on your flap wheel may result in tool wearing and ultimately shorter life.
  • It would be best if you work within the recommended peripheral speed. Exceeding the limit may damage your flap wheel.
  • Always use the appropriate grit for desired work. For example, if you use a fine grit for stock removal, naturally, the wheel will lose all the grains and end up before time.
  • Using grinding oil may increase the life of your flap wheel.
  • Always clean the tool after each use and place it in a safe and dry place.

Keeping all these factors in mind and working with the care, you can benefit from your flap wheels for many years.

Flap Wheels

What Are the Various Abrasive Materials Used on Flap Wheels?

Syndent manufactures a wide range of flap wheels in terms of the embedded abrasive material. Some are:

Aluminum Oxide

Aluminum oxide flaps are ideal for working on steel and other common metals. These are the durable flap wheels with stiffer, thicker, and tougher cloth backing.

The heavy-weight cloth is flexible, bendable, and tear-resistant and gives you efficient stock-removing results.

Zirconia Alumina

Zirconia alumina coated flaps are ideal for working on stainless steel and alloys resistant to high temperatures. The improved stock removal prevents clogging and results in cool grinding.

Ceramic Oxide Grain

These flap wheels are ideal for aggressive stock removal on challenging materials – non-heat conductors.

Silicon Carbide

Flaps coated with silicon carbide are suitable for tough and rigid materials like titanium alloys, copper, and bronze. These abrasives are ideal for giving the surface a fine finish.

Flap Wheel

Can a Flap Wheel Be Used on Wood?

Yes, anytime!

Syndent facilitates you with variable abrasive flap wheels. Wood is one of the ideal surfaces that can be treated with flap wheels.

You can conveniently grind, deburr, shape, and refine a wooden piece. Flap wheels are ideal rotary tools for sculptors and carvers.

The flexible fine-grit flaps impressively smoothen the wooden surface without damaging the minutely carved details.

The ductile flaps ensure to reach every corner and side of your workpiece and clean it. No doubt, it is a state-of-the-art rotary tool.

Flap Wheel

How Do I Use a Flap Wheel for Wood?

You can use flap wheels for wood in many ways. Like:

  • Sand a wooden surface with fine-grit flaps.
  • Remove paint from a wooden piece.
  • You can clean and smooth a carved wood piece conveniently with your flap wheel.
  • With coarse grit flaps, you can quickly cut and shape a woodblock.
  • Finally, with buffing wheels, you can prepare the surface for polishing.
  • Always remember to put minimal pressure on your flap wheel. Unnecessary stress may remove unwanted stock and may damage the shape of your wooden piece.

Can I Use a Flap Wheel on Aluminum?

Yes, of course!

Flap wheels are suitable for a wide range of metals and materials. The versatility of flaps allows you to work efficiently on variable surfaces in many ways.

You can conveniently grind, deburr, stock removal, cut, polish, and clean with Syndent’s flap wheels. Besides all the everyday purposes, flap wheels are ideal for preparing the aluminum surface for polishing.

You can smoothen the aluminum workpiece with flap wheels before polishing, or you can effortlessly polish the piece by yourself.

Flap Wheel

How Do You Use a Dremel Flap Wheel?

Dremel flap wheels are easy-to-use rotary tools. You can conveniently attach the mounted flap wheels to your Dremel grinder or drill.

The flexible flaps of Dremel flap wheels allow you to work on any surface without damaging the cuts and shapes.

Dremel flap wheels are also available in multiple sizes, shank lengths, diameters, grit numbers, and abrasive materials.

You can choose the best flap wheel according to your workpiece and requirement. While using your Dremel flap wheel you must take all the precautionary measures.

You must follow the recommended peripheral speed while working with your Dremel flap wheel.

Flap Wheel


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