Concrete surface polishing trowel and conversion adaptor

An adaptor assembly for concrete finishing trowels that enables efficient polishing of concrete surfaces, and trowels equipped with said adaptors. A large, rigid, circular adaptor disk supports a plurality of spaced-apart polishing rotors that project into contact with the concrete surface being treated. Each polishing head is rotatably secured to the adaptor disk with a spindle assembly including suitable alignment bearings. The spindle assembly secures a rigid header beneath the adaptor disk that sandwiches a resilient, annular coupler between itself and a rigid driver plate beneath the coupler. Bosses on the coupler insure spacing and enable proper flexure. The driver plate removably mounts a resilient finishing ring, that supports a plurality of radially spaced apart, downwardly projecting, diamond-equipped pucks that frictionally bear against the concrete surface for abrading and polishing.