United Fine Straight threads (UNF) are parallel, and are like the threads on a machine screw or bolt. They require a tapped hole for installation. Most commonly used on trucks, cars, and industrial machines.

 

Maximum Pressure is 8,000 PSI. All zinc dichromate fittings minimum 72 hours to red rust. All zinc fittings case hardened to Vickers HV1 or 83 min Rockwell 15N. All stainless steel fittings are type 303 stainless.