Technical Data

1. Hardness differences between HEICO-LOCK® and mating surfaces (HHEICO > HMaterial)

  • The hardness of the HEICO-LOCK® washer should exceed the hardness of the mating surfaces and is higher than structural grade and high tensile bolts and nuts (8.8, 10.9 an 12.9.)
  • Radial teeth/ridges on the outside of the washers grip into and seat the mating surface in the tightening process.

HEICO-LOCK® Hardness Table

Steel (1.1191)
(through hardened)
485 ±25 HV0.3
Stainless Steel A4 (1.4404)
(surface hardened)
> 520 HV0.05
Stainless Steel SMO 254 (1.4547)
( surface hardened)
> 520 HV0.05


                   Technical Data

2. Difference in the rise of HEICO-LOCK® cams and the pitch of the bolt

  • The rise of the cams α between HEICO-LOCK® wedge lock washers is greater that the pitch β of the bolt.
  • The elongation of the thickness of HEICO-LOCK® wedge lock washers is larger than the potential movement of the the bolt along the pitch. The lock washer prevents the bolt/nut from loosening due to vibration and the bolt/nut is locked safely in place.
  Technical Data

3. Differing Friction Coefficient between HEICO-LOCK® cams und radial ridges

  • The cams on the separation plane (joint face) of the individual washers of the pair show a much lower friction coefficient µi than the friction coefficient on the radial ridges on the outside of the pair of washers µa)
  • Any loosening through a dynamic load will always lead to movement only across the face of the cams of the washers.
  Technical Data

4. Securing the bolted joint through post tensioning (Fdyn > Fstat)

  • Loosening the bolt causes the pair of HEICO-LOCK® wedge lock washers to expand, thus actually increasing the clamping force. The result is an increase in the clamping force.
  • The expansion of the pair or washers increases the pre-load and locks the fastener securely, even when subjected to extreme vibration and dynamic loads.
  Technical Data

5. HEICO-LOCK® wedge lock washers with a large outside diameter

Large I.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.

  Technische Daten