Shakeproof Washers

A shakeproof washer - also known as a serrated or star washer - is the toothed metal washer that bites into the mating surface and the fastener bearing face to resist loosening under vibration, impact, and cyclic loading. At the DIY Hardware Store, our shakeproof washers are available in the metric sizes used across automotive, engineering, and general mechanical assembly applications where positive anti-rotation resistance is required at the fastener bearing point.

The teeth of a shakeproof washer are formed by cutting and deflecting sections of the washer disc to create sharp points that embed into both the nut or bolt head bearing face and the material surface when the fastener is tightened. This mechanical interference provides a positive locking action that a plain washer cannot - the points must be deformed or the fastener must be rotated with sufficient torque to override the locking teeth before the joint can loosen. Internal tooth, external tooth, and both-face (double serrated) formats are available for different fastener and joint configurations.

  • Serrated teeth bite into bearing surfaces to resist loosening
  • Positive mechanical locking under vibration and impact
  • Internal tooth, external tooth, and double-serrated formats
  • Metric sizes for automotive, engineering, and general assembly
  • Zinc-plated steel for general use; stainless for corrosive environments
  • Sold as singles and in packs