Abstract: A hard disk drive assembly having a pivoted arm that moves a read/write head over a hard disk from an inside diameter to an outside diameter, and an unadjustable, one-piece crash stop that limits the movement of the arm. A first version of the crash stop is an elongated member having a smooth bottom free of projections, and having first and second through holes. The hard disk drive assembly has a base having two threaded holes. The first and second through holes of the crash stop align with the two threaded holes when the crash stop is placed on the base. Screws are disposed in the first and second through holes and are threadably engaged with the two threaded holes in the base. The screws, when tightened, lock the crash stop in a precise location. In this version, one of the screws passes through a very closely-fitting precision round hole in the one-piece crash stop. That screw acts, in effect, like a locating pin. This version can be used without modifying the existing base of the hard disk drive assembly.