Fine Thread Nut

Fine Thread Series, UNF/UNRF: This is used for applications that require a higher tensile strength than the coarse thread series and where a thin wall is required.

Extra-fine Thread Series, UNEF/UNREF: This is used when the length of engagement is smaller than the  fine-thread series. It is also applicable in all applications where the  fine thread can be used

Fine thread:

1. Resistance to loose on vibrations

2. Lead distance is less between threads.