thumb|Early radial flapwheel, for use with an electric drill A flapwheel and the related flap disk is an abrasive disk, used for metal finishing. Unlike the simpler flat disks, made from a circular flat sheet of a coated abrasive, a flapwheel is made of multiple overlapping small pieces or 'flaps', bonded to a central hub.
thumb|Early radial flapwheel, for use with an electric drill A flapwheel and the related flap disk is an abrasive disk, used for metal finishing. Unlike the simpler flat disks, made from a circular flat sheet of a coated abrasive, a flapwheel is made of multiple overlapping small pieces or 'flaps', bonded to a central hub.
== Advantages == The advantages of a flapwheel over a traditional disk are twofold: The separate flaps each attack the workpiece surface at a slightly different angle, and this varies slightly with tool angle. This avoids the common problem with flat sheets, where they produce repeated identical scratches. Abrasive wear is distributed more evenly across the flaps, and through the length of each flap. Flaps wear from their outer ends and the sheet carrier cuts back as the abrasive coating is worn away. The wheel remains useful even as the flaps erode. Compared to flat sheets, that are discarded after only a small area of the abrasive is truly worn-out, this is a much more efficient use of the abrasive material.
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