一,、英制螺紋（螺紋牙型角55度）Thread of British standard ( Thread pitch shape angle 55°)

            BSW－－－－英國標(biāo)準(zhǔn)惠氏螺紋（粗牙）British Standard Whitworth Thread ( Coarse )

            BSF－－－－英國標(biāo)準(zhǔn)惠氏螺紋（細(xì)牙）British Standard Whitworth Thread ( Fine )

            G－－－－直管螺紋（外螺紋分A,、B兩面級(jí),、絲錐分G、G－D）Straight pipe thread ( Outside )

                      thread in A\B: taps in G,、G－D )

            R－－－－錐管外螺紋（舊代號(hào)ZG;KG）Outside paper pipe thread ( Old thread code  ZG,KG )

            RC－－－－錐管內(nèi)螺紋（舊代號(hào)ZG;KG）Inside taper pipe thread ( Old thread code ZG,KG )

            二,、美制螺紋（螺紋牙型角60度）Thread of American standard ( Thread pitch shape angle 60°

            UNC－－－－統(tǒng)一制粗牙螺紋（代替NC）Unified coarse pitch thread ( Instead of NC )

            UNF－－－－統(tǒng)一制細(xì)牙螺紋（代替NF）Unified fine pitch thread ( Instead of NF )

            UNEF－－－－統(tǒng)一制超細(xì)牙螺紋Unified superfine pitch thread

            UN－－－－－統(tǒng)一制不變螺距螺紋Unified thread

            UNS－－－－統(tǒng)一制特殊螺紋Unified Special thread

            NPT－－－－一般用途錐管螺紋（舊代號(hào)Z;K）Taper pipe thread for general purpose ( Old

                          thread code Z,K )

            NPSC－－－－管接頭直管內(nèi)螺紋Internal straight pipe thread for connection

            NPSM－－－－設(shè)備上自由配合,，機(jī)械連接用直管螺紋Straight pipe thread for general purpose

            NPTF－－－－干密封錐管螺紋Dryseal taper pipe thread

            NPSF－－－－干密封燃油直管螺紋Dryseal straight pipe internal thread

            NGT－－－－氣瓶用錐螺紋Special thread for gas cylinder

            三,、米制螺紋Metric thread

            ZM－－－－－米制錐管螺紋 Metric taper pipe thread

 四、其它螺紋Other threads

            SM－－－－縫紉機(jī)螺紋Thread for sewing machine

            PZ－－－－氣瓶用錐螺紋Special thread for gas cylinder

            5V1－20V1－氣門芯螺紋5V1－20V1－Tyre valve thread

            螺紋代號(hào)說明示例：Explanation of thread code. e. g.

            1/4－20UNC

            1/4－公稱直徑1/4" nominal dia. 1/4"

            20－每寸20牙twenty teeth per inch

            UNC－美標(biāo)統(tǒng)一制粗牙螺紋unified coarse pitch thread ( American standard