Based on the basic deviation and tolerance of GB/T 197-2003, this standard stipulates the limit deviation of pitch diameter and top diameter of ordinary thread (metric thread for general purpose). The basic profile and diameter and pitch series of ordinary threads comply with the provisions of GB/T 192-2003 and GB/T 193-2003 respectively. This standard applies to mechanically fastened threaded connections for general purposes, the threads themselves not having a sealing function.