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How to Select a Right Flap Disc?

How to Select a Right Flap Disc

Flap discs are the leading abrasives category in metal fabrication. They offer fast stock removal and supply grinding, blending, and finishing with one product, for a lower total cost. Flap discs feature cooler cutting with less gouging and burning.

Flap discs are preferred for several reasons, including lighter weight, easier-to-control, less downtime for product changes, less vibration and resulting fatigue, and also reduced noise.

Although, while selecting the flap discs for the job, it's essential to understand all the variables and how they apply to your metal fabricating application.

Selecting the right products for your metal grinding or finishing applications is extremely crucial because it will save time and price for the method.

Let's first understand a bit about flap discs.

What are Flap Discs?

Flap discs are constructed with multiple overlapping pieces of abrasives called 'flaps' and are an essential component of a grinder. They are designed for right angle grinder applications starting from heavy stock removal to surface blending and smooth finishing.

Flap discs are similar to emery wheels, but they yield very different results counting on the project.

Both the grinding wheels and flap discs grind metals effectively, and that they have great cut rates. However, they're costlier in comparison to grinding wheels.

They're made with an equivalent grain found in abrasives, but the grains' arrangement within the discs gives them a softer feel.

Flap discs are designed to be used with right angle grinder operations, and that they can meet your needs in several applications. While it takes a substantial amount of experience to use grinding wheels, flap discs have a smooth learning curve with a little error margin.

How to Select the proper Flap Disc

Select the right Flap Disc

Choosing the Right Abrasive

    The abrasive material of flap discs largely determines its effectiveness; the first types are:

    • Zirconium Alumina- It is a mix of zirconia grain and alumina with self-sharpening capabilities. This sort of flap provides a high bargain rate for rock bottom cost possible. It's tough, durable, and immune to heat, making it an ideal choice for low-carbon steel and carbon applications.
    • Ceramic Alumina - This grain is the newest innovation in abrasives, and it's especially effective on stainless and high-alloy materials. It provides the fastest cuts also as maximum utilization of the entire grain.
    • Aluminum Oxide- Aluminum Oxide Flap Disc is the oldest grain in metalworking, and it's highly recommended for little, low-cost tasks.

    When choosing the three types, you would like to think about increased longevity, reduction in downtime, and inventory reduction for different products. The foremost important thing is to seek out the flap disc that meets the precise requirements of any application within the specified time and budget.

    Proper Flap Disc Grit size

      Choosing the proper grit size goes to work out how fine or coarse. The sizes range from 4 to 7 inches to suit various right angle grinders. There also are custom flap discs that are made to satisfy specialized applications. Understanding the grit sizes will ensure the simplest grinding and finishing solution for metalworking. 

      • Flap discs are designed to be used on right-angle grinders at angles from 5 to 35 degrees. 
      • Grit size is the final component an end-user must select to match a flap disc to an application. The standard range is from 24 to 120 grit.
      • When performing heavy metal removal, selecting too coarse a grit can cause shelling, cautioned Norman of 3M, which offers abrasive as rough as 36 grit.

       Shape of the Flap Disc

      Flap discs are used on right angle-angle grinders, and that they are designed with a central point that permits work to be performed on the flaps. The flaps are often aligned at angles from 5 to 35 degrees.

      Picking the proper Flap Disc shape, conical shape (Type 29), or a flat shape (Type 27) provides different performance features.

      • Type 29 Conical flap discs are the most straightforward choice for aggressive stock removal. Conical flap discs have angled flaps and can be used on both contoured and edge work. They're the simplest choice when speed and stock removal are primary considerations.
      • Type 27 Flat flap discs are the simplest choice for finishing. Flat flap discs are used totally on flat surfaces. They're the simplest choice for blending and smooth finishing.

      Backing Plate Material

        When selecting a flap disc paint removal, you ought to also consider the fabric used on the backing plate where the abrasive flaps adhere. The backing plate offers stability during usage, and it's available in the following material types:

        • Plastic Backing Plates - Plastic backing plates are getting more popular as they are comfortable to use and trimmable, which allows more use of the flaps, especially for blending and finishing
        • Fiberglass Backing Plates - Fiberglass backing plates help in absorbing vibrations. Fiberglass is the most popular material because of its high strength and lightweight.
        • Aluminum Backing Plates - Aluminum backing plates are the least popular, but are good in applications demanding extra high strength and rigid support. While not consumable during use, an aluminum plate can be recycled  

          The density of the flaps

      1. Standard density: A typical density is best fitted to light-duty applications requiring fast stock removal.
      2. High density: As the name denotes, this density is applicable when performing on high-demanding applications and finishing as curved and uneven jobs.


        With the growing innovations, flap discs are available to use on various surfaces, unlike in the past, where they were only used on metals. Today, many types of flap discs are available that will work on wood, to remove paint and concrete, and more. For every one of those applications, the foremost important thing is to settle on the proper disc to achieve the specified efficiency and effectiveness level.

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