Leveraging the power of the wedge principle used in ancient Japanese architecture, the HARDLOCK® Nut is the ultimate self-locking nut which completely integrates the nut and the bolt.

Self-locking effect recognized by the world

The HARDLOCK® Nut passes United States NAS (National Aerospace Standard) aviation standards.

Torque and Axial Force control

Control the axial force with proper torque wherever used.


Made of all metal with little few wear surfaces, sustains a powerful self-locking effect.

Easy and efficient

Can be easily installed with just one commercially available tool.


Reduced maintenance and labor add up to a significant savings in overall costs.

Self-locking design

The HARDLOCK® Nut has a structure that prevents looseness through the traditional Japanese principle of the wedge. To effectively utilize the wedge structure, two nuts are used: (1) a convex nut with an eccentrically formed boss, and (2) a perfectly circular concave nut. When these nuts are fastened together, the wedge principle mechanically creates a powerful locking effect transverse to the bolt shaft. This powerful anti-loosening effect achieved with the HARDLOCK® Nut wedge completely fuses the bolt and nut. Once locked with this powerful force, the HARDLOCK® Nut is not susceptible to impulsive forces or shocks.