FUJILOK U-nut – The Locknut with the stainless steel insert


The Fujilok U-nut has an international reputation built on over 30 years. The Fujilok U-nut is used worldwide in many engineering applications. It is recognized as the most reliable of all metal locking nuts. The Fujilok U-nut can be customized to fit your unique requirements with regard to material, dimension, and finish. Fujilok U-nut is used by Government civil and defense projects, public utility corporation (water, energy), railways, and many leading manufacturers.



The Fujilok U-nut comprises a nut and friction ring (special spring stainless steel). The friction ring is attached to tha top face of the nut by crimping. The Fujilok U-nut is comprised of a nut and stainless steel friction ring spring.


A stress (P) is produced by the spring effect of the stainless steel friction ring coming into contact with the screw thread as shown in the above illustration. The (P) and its reaction force (P’) press strongly against the screw threads?to produce a frictional torque (prevailing torque). This prevailing torque prevents the turning of the screw, generation an excellent locking effect.


Product types



Fujilok U-nut are used for fastening especially in important areas. When using Fujilok U-nut, the best results are achieved by adhering to the following simple requirements.