Security locknut

This isolates the loading and locking functions and helps prevent the nut from backing off the bolt.

Due to the durable spring steel alloy, the security locknut is fully reusable while maintaining prevailing torque in each application.

They are most commonly used in high vibration environments where non-locking nuts could come loose.

In the rail industry, security locknuts can be found most commonly on railroad fishplates, frogs, switches, and crosses.

Heavy vibration equipment manufacturers[3] use security lockouts on woodchippers, grinders, pulverizers, shakers, feeders, and more.

A hexagonal security locknut threaded onto a railroad track bolt.
Several security locknuts being used on bolted joints on vibratory equipment.