Mounted Vs Unmounted Flap Discs

A flap disc is an abrasive disc with die grinders and angle grinders. It differs noticeably from a flap wheel. They are made of coated abrasive flaps that overlap and are connected radially to a backing plate, giving them the appearance of overlapping pieces of sandpaper. Additionally, they have a quick change connection, a screw-on/screw-off hub, or an open center hole.

Flap discs, in contrast to traditional grinding wheels, are composed of flaps formed of abrasive materials. They can now be found in various materials and grit sizes. Each abrasive sheet is the same size and is made up of x-weight fabric flaps bonded to grains of abrasive material resembling sandpaper. With use, flap wheels will degrade, supplying new abrasives for a steady cut and extended use. This kind of material works well on large work surfaces, curved or uneven surfaces, including pipelines and tubes.

Mounted Wheels

Mounted wheels are typically used on portable tools and have a diameter of 3" or less. It is possible to have mounted wheels with an 18" or 14" straight shank or a 14-20 male threaded shank. For precision work with MFW in the diameter range of 3/8" to 1 3/16", the 1/8" shank is employed in the mold and die business. The most widely used shanks are a 14-20 threaded shank and a 14" straight shank.

Unmounted Wheels

Unmounted flap wheels are made with abrasive flaps forming a fan-shaped wheel around an arbor hole. The flap wheels can be connected via the arbor hole to bench-top grinders, pedestal grinders, and other straight finishing tools.

The larger wheels, which have a diameter of 4 inches or more, are used on stationary tools. A similar configuration of flaps radiating from a central core is seen on unmounted wheels. UMFW are attached to a spindle using flanges and have an arbor hole. The unmounted flap wheel has a face width of 4 inches and a maximum diameter of 16 inches.