UNF Bolts

UNF thread bolts adhere to the Unified National Fine (UNF) thread standard. UNF threads are characterized by their finer pitch compared to the Unified National Coarse (UNC) threads. These threads have a higher number of threads per inch, resulting in a tighter and more precise fit when engaged with a mating part.

UNF threads are designated by specifying the nominal diameter followed by the number of threads per inch. For example, a bolt with a 1/4-inch diameter and 28 threads per inch would be denoted as 1/4-28 UNF.  UNF threads have a finer pitch than UNC threads. This means there are more threads per inch, resulting in a greater number of engaged threads and a stronger connection.

UNF thread bolts are commonly used in applications where a higher degree of thread engagement and strength is required. They are often found in industries such as automotive, aerospace, machinery, and precision equipment.  Due to their increased thread engagement, UNF thread bolts offer improved load-bearing capacity compared to UNC thread bolts of the same size. They are better suited for applications requiring higher tensile strength and resistance to vibration.

We stock part thread and full thread bolts (often referred to as a setscrew). Finishes include zinc plated, stainless and unplated self colour. They are high tensile bolts Grade S/5. Available UNF diameter sizes 10/32", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 3/4", 7/8", 1", 1 1/8", 1 1/4", 1 1/2"