Abstract: An abrasive nozzle assembly comprises a casing, a nozzle head and an abrasive nozzle mounted coaxially to generate a high-velocity abrasive airstream. The nozzle head has a cavity with a nozzle orifice. The casing includes an air passage, which communicates, at one end, with a compressed air supply tube and, at another end, with the cavity. The abrasive nozzle includes an abrasive supply tube which passes axially through the casing and cavity to terminate at the nozzle orifice. A compressed air source feeds the compressed air supply tube. An abrasive mixture source feeds the abrasive supply tube. The abrasive nozzle acts as a primary nozzle directing a narrow abrasive airstream from the center of the nozzle orifice. The nozzle head, which acts as a secondary nozzle, discharges a ring-shaped, high-velocity, abrasive-free airstream from the periphery of the nozzle orifice.