Example - Typical designation of an UNC thread 1/4” x 20 UNC US Bolts - Tightening Torques UNF - Unified National Fine Threads UNF threads ANSI B1.1: UNC and UNF - Unified Inch Screw Fine Threads Major Diameter (in)Threads per inch(tpi)Major DiameterTap Drill Size (mm)Pitch (mm) ...
Thread Count (TPI) Explained - TPI stands for Threads Per Inch which is simply a count of the number of threads per inch measured along the length of afastener. This description is used only with American fasteners. Metric Fasteners use a thread Pitch to designate different thread sizes....