Flap Discs

RockRidge flap discs offer versatility allowing the user to grind stock and finish the surface in a single operation. The abrasive-coated flaps are adhered to a rigid backing. The back plate provides stability during operation allowing a cooler cut, less vibration, and a smoother finish. The layered flaps aid in decreasing gouging on the metal being worked on. Flap discs are applicable from stock removal to blending the surface. 

RockRidge flap discs are available in either zirconia alumina or ceramic abrasive grains. RockRidge's flap discs are sold in two different shape styles as well, type 27 or type 29.

Flap Disc Shape Types
Zirconia Flap Discs

Zirconia Alumina

The zirconia alumina grain is a medium hard grain that is also very sharp, tough, and heat resistant. Those qualities make it the ideal abrasive type for heavy machining under heavy to very heavy pressure. Heavy pressure and exposure to heat causes the grit to break open which constantly creates new cutting edges. This prevents the grit from ever becoming prematurely blunt. Zirconia alumina achieves best performance with coarser grits, like 24 through 80 grit. These discs are available in standard or heavy duty density flap discs. 

Ceramic Flap Discs


Ceramic grain has a micro-crystalline structure that is hard and tough, but at the same time very sharp. Due to the micro-structure of the grain, the grit begins to break at low to medium pressure. The new cutting edges created ensure that the machining capacity of the grit has very little diminish during the product's lifespan. The properties of the ceramic grain can change in an adverse way under the influence of heat, therefore, active grinding agents help prevent heat build up with this material.