This standard specifies the limit dimensions of common threads based on GB/T 193-2003 "Ordinary Thread Diameter and Pitch Series" and GB/T 197-2003 "Ordinary Thread Tolerance". The basic profile of common thread conforms to the provisions of GB/T 192-2003 "Basic Profile of Common Thread". This standard is applicable to commonly used ordinary threads with a nominal diameter of 1 mm to 300 mm and a tolerance zone of 4H, 5H, 6H, 7H, 6G, 4h, 6h, 6g and 6e.