Self-locking nuts demonstrated to exhibition visitors

These nuts utilise the wedge effect and meet - or exceed - a number of different standards. They are also approved for use on rolling stock, signals and track in the UK.

The nuts come in pairs, one with an eccentric conical protrusion and the other with a concentric conical recess. When applied to a standard bolt, the nuts' conical forms work together to create an axial load and two radial loads - the nut with the protrusion is forced onto the bolt in one direction while the nut with the recess is forced onto the bolt in the other direction.

Unlike many other types of locking nut, the Hard-Lock nuts can be reused repeatedly. They are available in metric sizes from M6 to M39.

For other sizes and less demanding applications, Staytite also supplies several alternative types of locking nut: Stayloc nuts, Bi-Way nuts, barb nuts, Carp nuts and serrated flange nuts.