Fuji Bearing Lock Nuts

eliminate keyways and tab washers

notes on use

Fine-U-Nuts are used for fastening critical components.  When using Fine-U-Nut, strict compliance with the following is required:

A lead in chamfer equivalent to one thread pitch is required. The screw thread should be to ISO 965. (Tolerance Class 6g).


Lubricate the shaft before assembly or removal of the nut. With shafts of low hardness use a high performance lubricant.

To maximise effectiveness ensure there are at least two full threads beyond the friction ring.


The squareness specified for the mating face is achieved with a tightening torque equivalent to x2 the prevailing torque - see our literature.


Do NOT use a high rotational speed impact wrench.


Do NOT use the nuts on shafts with keyways.


Do NOT screw in the nut from the friction ring side.


Stop using the nut when excessive deformation or other fault is found in the friction ring and the clamp.


For severe or unusual applications please ask for our advice on 01202 339559.




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