Abstract: A screw locking arrangement comprises an article having a threaded aperture with an enlarged counterbore. A slot is positioned in the side wall of the counterbore and extends through the top surface of the article. A screw is threadedly engaged in the aperture and includes an enlarged head with a slot disposed in the outer marginal surface thereof. A deformable lock member is positioned in the counterbore and has a wall between the counterbore side wall and the marginal surface of the screwhead, and the wall is bent by a suitable tool into both of the slots, thereby positively locking the screw and the article together without indexing the same.