Coarse Thread Vs Fine Thread Fasteners

Most hardware products(nuts and bolts) you purchase will be Unified National Coarse which is abbreviated (UNC).  This thread pitch is great for projects that require quick assembly. The coarser thread pitch also reduces cross threading incidents.

Unified National Fine Thread abbreviated (UNF) have more threads per inch than course nuts and bolts. UNF products are great for projects that require a high level of precision. These fasteners tend to have a higher tensile strength. Because of the finer thread caution needs to be taken to ensure you do not strip the threads.