A loose bolt can cause catastrophic machinery failure. While a standard flat washer distributes pressure, a spring lock washer adds active mechanical tension to the joint. These small, split components are critical for high-vibration applications.

What is a Spring Lock Washer?

A spring lock washer is a metal ring split at one point and bent into a helical shape. This design allows the washer to act like a spring when compressed between a nut and a mating surface.

   Normal State         Compressed State
    _   _                  _______
   / \ / \                |_______|

  |_/   \_|             
(Helical Split)        (Flattened Tension)

How They Work

Spring lock washers prevent loosening through two distinct mechanisms:

• Preload Tension: Compression flattens the helical shape, creating continuous upward force against the fastener head.
• Frictional Resistance: The sharp edges at the split bite into the nut and the mounting surface, physically resisting counter-clockwise rotation.

Best Practices for Installation

Maximising the effectiveness of a lock washer requires proper installation techniques.

• Placement: Always place the lock washer directly under the nut or bolt head being turned.
• Combination: Use a flat washer underneath the lock washer if you are fastening into soft materials like aluminum or plastic to prevent surface damage.
• Torque: Tighten the fastener until the lock washer is completely flat. Over-tightening can crush the washer and destroy its spring properties.