LOCKING FASTENER

Locking Fastener

Locking fasteners are designed to prevent unintentional loosening or backing out. This is particularly important in applications where vibration, shock, or other forces could cause fasteners to loosen over time.
Common Types of Locking Fasteners :
  • Locking nuts: These are nuts with features that prevent them from loosening. Some common types include:
  • Castle nuts: Have a slot that allows a cotter pin to be inserted through the nut and a bolt, preventing the nut from turning.
  • Jam nuts: Are slightly smaller than standard nuts and are used in pairs. The second nut is tightened against the first, preventing both from loosening.
  • Nylon insert nuts: Have a nylon insert that creates friction between the threads of the nut and bolt, preventing loosening.


  • Locking screws: These screws have features that prevent them from loosening. Some common types include:
  • Set screws: Have a pointed tip that digs into the mating surface, preventing the screw from turning.
  • Slotted pan head screws with locking washers: The washer has a serrated edge that digs into the surface of the mating material, preventing the screw from turning.
Applications of Locking Fasteners:
  • Aerospace:Used to fasten components in airplanes, helicopters, and spacecraft.
  • Automotive: Used to fasten components in cars, trucks, and other vehicles.
  • Construction: Used to fasten components in buildings, bridges, and other structures.
  • Manufacturing: Used to fasten components in a variety of products, from electronics to appliances.