Abstract: A flap disc consists of a backing plate to whose peripheral zone laminae overlapping like a fan or roof tiles are attached. In order to improve the abrasive effect of such a flap disc using less material and simpler production, the lamellae 10 consist of first lamellae 12, comprising a backing 14, a base bonding coat 15 applied to the backing, a layer of abrasive grain 16 deposited over the base bonding coat 15, and a size coat 18 over the layer of deposited abrasive grain 16, and second lamellae 20, consisting of a backing 22 and a layer 24 with grinding active fillers applied to the backing.

Abstract: A pasty mix of granular grits, binder and filler is pressed through a sieve web by rolling action to form cylindrical, worm-like extrusions. After hardening in a heating duct the extrusions are subjected to the same action and thereby granular grit particles are formed each of which contains several grits.The apparatus for carrying out the method includes a sieve web which co-operates with a rotor having several freely rotatable rollers around its periphery.