[computerworks]

The upper portion of the tapped nut is compressed to an elliptical form to create a locking zone. The lower zone of the nut maintains its form.
The mating external thread assembles freely in the lower zone of the STOVER locknut. As the mating external thread advances into the nut, it makes contact with the locking zone, expanding it to an almost circular shape. This creates a compressive force on the mating external threads. This compressive force provides the prevailing torque locking action.