Wedge-Lock Washers

Bolted connections tend to work themselves loose under certain operating conditions. Vibrations cause particular problems as they can overpower the “self-locking effect” of bolted connections. This can lead to functional failure or even lead to the connection coming apart. As it’s not always possible to know what forces are acting on the structure, and as constructional measures cannot be implemented everywhere, securing elements are often used.
One of the few effective securing technologies available is the HEICO-LOCK® wedge locking system, the effectiveness of which has been demonstrated by the latest experimental standards (including DIN 65151, DIN 25201-4, NASM 1312-7).


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 with Wedge-shaped cams on the inside of the lock washers, radial teeth on the outside. Interlocking embedding of the radial teeth with the respective mating surface (when tightening the bolted joint)
System movement is only possible between the inner wedge shaped cams.   Movement across these wedge shaped surfaces effectively self locks the bolt leading to increase in clamping force.


Certified system for securing bolts, works at low and high preload levels.
Particularly suitable for dynamic loads – including when using lubricants.
Can be re-used.
Very easy to install and remove (wedge lock washers are supplied as a pre-assembled pair)
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 are available upon request.
Available from M3 – M76 and ¼” – 3” – customised sizes upon request


The Junker vibration test meeting DIN 65151 (Dynamic testing of the locking characteristics of fasteners under transverse loading conditions – vibration test) standards is a common and reliable method for testing and comparing the security of bolted joints.

The Junkers test is considered a ‘severe’ test of the loosening characteristics of fasteners, particularly when compared to previously introduced test methods which rely on axial dynamic loading to induce loosening.

Watch a detailed demonstration of the Junkers Test below.

Product Range

The above available with standard diameters – HLS and larger outer diameter HLB for soft surfaces and slotted holes.

Usage Recommendations

Through-holes require the use of two pairs of Heico-Lock washers.

One pair for securing the bolt and a second pair for securing the nut. Turn both fasteners in order to close the cams on both washer pairs before tightening to minimize settlements. Keep the bolt secure whilst tightening the nut.














Designs where Heico-Lock washers are not recommended:

  • With chamfered plain washers.
  • Mating surfaces that are not locked in place.
  • Mating surfaces harder than the washers.
  • Extremely soft mating surfaces (e.g. wood, plastic).
  • Applications with extremely large settlements.