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 (e.g. strength classes: 8.8, 10.9,12.9)
  • Radial teeth/ridges on the outside of the washers grip into and seat the mating surface in the tightening process

Material information

Material Hardness Corrosion
Steel (1.1191 / C45E)
(through-hardened, zinc flake coated)
485 ±25 HV0.3 Min. 600h in neutral
salt spray test (acc. to ISO 9227)
Stainless Steel A4 (1.4404 / 316L)
(surface hardened)
> 520 HV0.05 Min. 1.200h in neutral
salt spray test (acc. to ISO 9227)

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
KSS Langloch

5. HEICO-LOCK® Wedge Lock Washers with a large outside diameter

Large O.D. HEICO-LOCK® Wedge Lock Washers are recommended for use on large/long holes (for example with flange nuts or screws), painted surfaces or soft materials, for example aluminum.

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