A nozzle is releasably locked in a drilling fluid passage of a rotary rock bit by a retainer member which bridges between matching grooves in the periphery of the nozzle and in the wall of the passage respectively. The retainer member is introduced to the matching grooves through a first passageway that extends from the surface of the bit to the matching grooves. The grooves lie in a common plane. A second passageway extends at an angle to the common plane from the surface of the bit to the matching grooves. A drive-out tool is inserted through the second passageway to remove the retainer member.