Abstract: A flexible abrasive rotary tool includes a hub adapted to be driven for rotation. Secured to the hub are discrete bristle tufts of stiff yet flexible abrasive loaded plastic monofilaments which project radially outwardly and then circumferentially away from the intended direction of rotation of the tool in the general form of a spiral so that the filaments of the distal end of each tuft extend generally circumferentially and overlies the filaments of the next adjacent tuft. The outer end of each tuft is resiliently radially supported by such adjacent tufts. The bristle monofilaments are preferably nylon and loaded with about forty-five percent of abrasive material and have a rectangular or somewhat oval sectional configuration so that the wider side of the monofilament forms the tool face. The tool has a number of applications but is particularly adapted to be circumferentially compressed into a bore or cylinder, such as that of an internal combustion engine.