A Nylock Nut (or Nylon Insert Lock Nut) is a type of lock nut that features a nylon insert within its inner thread. This insert creates a friction fit with the bolt or screw, preventing the nut from loosening due to vibrations or torque. The nylon insert also helps to reduce the risk of damage to the bolt's threads, ensuring a secure and reliable connection. ... Nylock nuts are commonly used in automotive, machinery, and electrical applications where vibration resistance is critical. They are available in various sizes and materials, such as stainless steel or carbon steel, and provide an effective solution for securing fasteners without requiring additional locking mechanisms.