• FREE Delivery on orders over £50
  • Over 35,000 products available
  • Established for over 10 years

Locking Washers

Locking Washers are used to prevent threaded fasteners from being loosened by vibration.

There are several types of washer that are designed to counter the problem of vibratory loosening:
  • Spring Washers are compressed when the fastener is tightened up. As a result, they exert pressure on the fastener and the substrate, with the effect that they maintain friction within the assembly when back-out begins to occur, which slows the rate of loosening.
  • Serrated Washers have teeth that bite into both the fastener and the substrate, which prevents the fasteners from loosening, but causes superficial damage to both the surfaces.
  • Schnorr Safety Washers combine the locking abilities of conical spring washers and serrated washers.
  • Nord Lock Washer Diagram
    Nord Lock Washer in use
  • Nord Lock Washers have a unique locking method, in which pairs of washers interlock with cams that have a steeper angle than the thread pitch. The result is that when back-out begins to occur, it exerts increasing force on the underside of the fastener and on the substrate because the expansion of the pair of washers exceeds the growth of the gap between the fastener and substrate. Unlike a spring washer, a Nord Lock washer is capable of stopping the loosening completely.