The thread size of a metric nut or bolt is listed as the letter "M" followed by a number that indicates the nominal diameter in millimeters, and then the thread pitch. This standardized system simplifies the process of selecting the correct mating components. For example, an "M8" metric fastener indicates a nominal diameter of 8 millimeters. The thread pitch, often included after the diameter (e.g., M8 x 1.25), specifies the distance between threads. Understanding this designation is crucial for ensuring proper fit and secure connections in various applications when working with metric fasteners. Forch Australia offers a wide range of metric fasteners to meet your project needs.