Serrated lock nuts resist rotation by gripping the mounting surface with a series of angled ridges on their bottom face. This gripping action prevents unwanted rotation where high levels of vibration may be present. They are better able to resist rotation than lock nuts with washers and nylon insert lock nuts.

Lock nuts with washers resist rotation using an integrated external tooth washer. They are stronger than nylon insert lock nuts when resisting rotation. They save time in assembly and manufacturing settings by eliminating the need for a separate lock washer.

Self-threading lock nuts create their locking threads when they are fastened into place. They are made of a deformable material like nylon and temporarily conform to the male threaded fastener. They are better able to resist rotation than nylon insert lock nuts but are weaker than lock nuts with washers.

Nylon insert lock nuts are used where vibrations may loosen the nut prematurely. They use a deformable nylon insert to engage the male threads and temporarily lock them into place. They are reusable but not heat-resistant and are the weakest style of lock nut.

Distorted thread lock nuts engage the male fastener with slightly deformed thread sections that friction fit into place. Some are reversible, with the locking threads in the middle of the nut. Others have their locking section offset towards one end or the other and are intended to be installed from one direction. These nuts resist rotation better than serrated lock nuts. They are commonly used in high-heat applications where nylon-based locking methods would melt or become ineffective.

Flexible top lock nuts elastically deform around the male threaded fastener using wings cut into the nut. This provides a reusable locking fastener that resists vibration and unwanted rotation better than distorted thread lock nuts.

Slotted and castle nuts feature slots cut into the body of the nut. These slots allow a cotter pin to be inserted through a hole in the male fastener, preventing the nut from unintentionally loosening. Castle nuts feature a reduced profile for use where clearance is limited.