Hard Lock Industry’s self-locking nuts are designed to withstand loosening from vibration that often occurs in fastener assemblies. The workholding system combines a centered concave top nut and an off-center convex lower nut to form a wedge when tightened. Force is applied perpendicular to the bolt, and the self-locking force of the wedge resists loosening when the top and bottom nuts are tightened. The nuts are said to withstand even repeated vibrations and shock.
Previously offered only in metric sizes, the nuts now are also available in inch sizes ranging from 1/4" to 1" in 1/16" increments.