HEICO-LOCK® wedge lock washers

HEICO-LOCK® Wedge Lock Washers

The HEICO-LOCK® wedge locking system delivers high quality anti-vibration security for the most demanding of bolted joint applications. Even under extremes of vibration or dynamic loads, HEICO-LOCK® wedge lock washers provide Maximum reliability. When the bolt is tightened, the external radial teeth of the HEICO-LOCK® wedge lock washers embed themselves in an interlocking fashion with the respective mating surface. If the securing system is subject to dynamic stress, movement is only possible between the internal washer surfaces. This results in an increase in the preload force.



  • Certified system for securing bolts, working at low and high preload levels
  • Particularly suitable for dynamic loads – including when using lubricants
  • Can be re-used without any reduction in function or quality
  • Very easy to install and remove (wedge lock washers are supplied as a pre-assembled pair)
  • Also suitable for high-tensile bolts of 8.8, 10.9 and 12.9 and their respective nuts
  • Available in steel or stainless steel with narrow or wide bearing surfaces – other materials such as Inconel and SMO are available upon request
  • Available from M3 – M76 and ¼” – 3” - custom sizes upon request


Functional principle


An important feature of HEICO-LOCK® wedge lock washers, setting them apart from other systems that are available, is the securing of the bolt fastening using preload force rather than friction


  • Wedge-shaped surface on the inside of the lock washers, radial teeth on the outside
  • Interlocking embedding of the radial teeth with the respective mating surface (when the bolt is tightened)
  • System movement only possible between the inside washer surfaces, allowing the securing system to readjust itself automatically
  • Increase in clamping force


Technical data


1. Difference in hardness: HHEICO > HMaterial

  • The surface hardness of HEICO-LOCK® wedge lock washers is greater than that of structural grade and high tensile bolts (8.8, 10.9,12.9)
    • Steel (through-hardened) 485 ±25 HV0.3; zinc flake coated
    • Stainless steel (surface-hardened) > 520 HV0.05

2. Difference in angles: α > β

  • The wedge angle α between the HEICO-LOCK® wedge lock washers is greater than the pitch β of the bolt thread
  • This angle means the expansion in thickness of the HEICO-LOCK® wedge lock washers is greater than the possible longitudinal movement of the bolt along the thread

3. Difference in friction: μa > μi

  • The wedge-shaped surfaces have a considerably lower friction coefficient μi than the toothed outside of the washers (friction coefficient μa)
  • Loosening caused by dynamic stresses causes movement between the two washers in the region of the wedged surfaces

4. Difference in preload: Fdyn > Fstat

  • An expansion in thickness of the HEICO-LOCK® wedge lock washers as a result of loosening leads to an increase in the clamping force
  • This causes an increase in the preload compared to when in a static state and thus causes the bolt to self-lock


Installation examples

Hexagon bolt in a through-hole, secured on both sides   Hexagon bolt secured in a blind hole   Countersunk socket head bold secured in position   Secured stud bolt   No locking function when combined with flat washers


Fields of application





HEICO-LOCK® washers are available in special materials and dimensions - talk to us concerning your special requirements.

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