The rotary flap or finishing wheel or tool has a plurality of radially extending finishing units or packs mounted in a circumferential series on a hub structure. The finishing units are mounted on the body structure by a dual clip-type assembly including an inner axially elongated and rigid clip member forming the primary component of the pack and an axially elongated outer clip member supporting or carrying the finishing or fill material and forming the secondary components of the finishing unit. The mount of the inner clip member is afforded at an inner axially extending through-bore therein which encircles an axial pin component located adjacent the outer periphery of the hub structure. The inner clip member has an axially elongated, keyhole-type slot or groove that opens re-entrantly along the entire axial length of the outer free clip end. Replaceable units of fill or finishing material are each constituted in part by the secondary or outer clip component or member having radial arms which are coextensive in axial length with the finishing material and are stapled in place within the latter. The arms integrally connect with one another at a radially inner bight at which, along with a telescoped inner wear sleeve, the pre-assembled finishing unit-secondary clip member is telescoped into the re-entrant keyhole recess of the primary clip member. Either one or both of the clip members of each finishing unit are mounted for pivotal movement.