HARDLOCK - Self-locking nut!

The worlds strongest self-locking nut!

The Hardlock Nut will stay intact through heat, high power throughput and the most severe vibrations. Japanese Railways have specified Hardlock Nuts for more than 40 years.
In the UK, Network Rail have specified Hardlock Nuts for over 10 years, with new applications being added to all the time.

A better fastener because it resists loosening by vibration
Easy to fit – Combines the benefits of a free-fitting nut and a self-locking nut
Reduced inspection and maintenance time
Reusable – Can be fitted after removal, saving time and money

How does it work?

Hardlock Nut consists of a (red) Convex "fixing" Nut that has a truncated protrusion arranged off-center on the upper part, the (green) Concave "locking" Nut is designed with a concentric conical depression for locking the two nuts together.

By tightening the concave nut onto the convex nut, a strong perpendicular load will be applied to the bolt from both sides. Due to the strong locking force created by the Wedge of the Hardlock Nut, no matter if it is exposed to severe vibrations and/or impacts the Hardlock Nut will stay intact.