This Drawing is of Detail of Self locking nuts. A locknut, also known as a lock nut, locking nut, self-locking nut, prevailing torque nut, stiff nut or elastic stop nut, is a nut that resists loosening under vibrations and torque. Prevailing torque nuts have some portion of the nut that deforms elastically to provide a locking action. Nut plates are self-wrenching, self-locking nuts that are used in constrained areas to provide a permanent nut element on the inside of a joint, so that an access panel, fairing, or other element can be attached with a screw. For the sake of simplicity, only three typical kinds of self-locking nuts are considered in this handbook: the Boots self-locking and the stainless steel self-locking nuts, representing the all-metal types; and the elastic stop nut, representing the fiber insert type. For more details and information download the Drawing file.