Tri-Loc Nut

A tri-loc nut is a prevailing torque locknut with a distorted top thread. The distortion grips the bolt and resists loosening.

A tri-loc nut locks a bolt or stud in place where vibration can loosen a standard nut. It takes a bolt or stud of the same thread and class. A washer is often used under the nut to spread the load.

This nut is often made in stainless steel. That gives good corrosion resistance for outdoor or damp locations.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance to the standard and material grade. On receipt, check the thread form and that the locking action is present but not so tight that it damages the bolt.