Internal – external teethed lock washers

Description

Internal–external teethed lock washers have teeth that extend both inward from the inside edge of the washer and on the outer edge and are particularly effective on flat bearing surfaces, when the diameter of the bore is significantly larger than the diameter of the screw.
The teeth bite into the bearing surface and the underhead of the bolt to oppose the loosening force.
Internal-external toothed washers are normally designed for use with bolt/nut assemblies involving fasteners of a property class less than 8.8.