What is a UNJF thread chart?

UNJF thread charts describe dimensions for fasteners adhering to the Unified Thread Standard. Typical dimensions on a UNJF thread chart include thread standard, pitch, diameter and tolerance. A UNJF thread chart may also include applicable standards based on fastener.

UNJF fasteners are very similar to UN and UNC fasteners and are derived from the same specifications. The major difference with UNJF fasteners is that they have a larger root radius than other Unified Thread Standards. This larger root radius improves the fasteners tensile stress area, which makes the fastener stronger. The tolerance for these dimensions is also tighter and is measured during quality inspection.