螺纹基本尺寸对照表精编版

英制管螺纹基本尺寸及公差（牙形角55o）BSPP螺纹代号G1/8″×28G1/4″×19G3/8″×19G1/2″×14G5/8″×14G3/4″×14G1″×11G1.1/4″×11G1.1/2″×11G2″×11G2.1/2”X11G3”X11G3.1/2”X11基本直径内螺纹外螺纹A级B级大径中径小径中径公差小径公差中径公差大径公差中径公差大径公差9.7289.1478.566+0.170+0.28200000-0.107-0.214-0.214-0.21413.15712.30111.445+0.125+0.445-0.125-0.250-0.2500-0.25016.66215.80614.950+0.125+0.445000000-0.125-0.250-0.250-0.25020.95519.79318.631+0.142+0.541000000-0.142-0.284-0.284-0.28422.91121.74920.587+0.142+0.541000000-0.142-0.284-0.284-0.28426.44125.27924.117+0.142+0.541000000-0.142-0.284-0.284-0.28433.24931.77030.291+0.180+0.640000000-0.180-0.360-0.360-0.36041.91040.43138.952+0.180+0.640000000-0.180-0.360-0.360-0.36047.80346.32444.854+0.180+0.640000000-0.180-0.360-0.360-0.36059.61458.13556.656+0.180+0.640000000-0.180-0.360-0.360-0.36075.18473.70572.226+0.217+0.640000000-0.217-0.434-0.434-0.43487.88486.40584.926+0.217+0.640000000-0.217-0.434-0.434-0.434100.33098.85197.372+0.217+0.640000000-0.217-0.434-0.434-0.434英制锥管螺纹基本尺寸及公差（牙形角55o）BSPT基面上的直径基准长度有效螺纹长度圆锥内螺纹基面轴向螺纹代号大径中径小径基本最大最小基本最大最小位移偏差（±mm）R1/8″×289.7289.1478.5664.04.93.16.57.45.61.1R1/4″×1913.15712.30111.4456.07.34.79.711.08.41.7R3/8″×1916.66215.80614.9506.47.75.110.111.48.81.7R1/2″×1420.95519.79318.6318.210.06.413.215.011.42.3R3/4″×1426.44125.27924.1179.511.37.714.516.312.72.3R1″×1133.24931.77030.29110.412.78.116.819.114.52.9R1.1/4″×1141.91040.43138.95212.715.010.419.121.416.82.9R1.1/2″×1147.80346.32444.84512.715.010.419.121.416.82.9R2″×1159.61458.13556.65615.918.213.623.425.721.12.9R2.1/2”X1175.18473.70572.22617.521.014.026.730.223.23.5R3”X1187.88486.40584.92620.624.117.129.833.326.33.51R3.1/2”X11100.33098.85197.37222.225.718.731.434.927.93.5美制管螺纹基本尺寸及公差（牙形角60o）UN(F)螺纹代号7/16″×20UNF1/2″×20UNF9/16″×18UNF3/4″×16UNF7/8″×14UNF1-1/16″×12UN1-5/16″×12UN1-5/8″×12UN1-7/8″×12UN2-1/2″×12UN9/16″×18UNF11/16″×16UN13/16″×16UN1″×14UNF1-3/16″×12UN1-7/16″×12UN1-11/16″×12UN2″×12UN5/8″×18UNF1-1/16″×14UN外螺纹内螺纹公差等级公差等级2A2B大径中径小径小径中径大径最大最小最大最小最小最大最小最大JIC螺纹11.07910.87410.25410.1479.5689.72810.03310.28710.42411.11312.66712.46111.84111.73211.15611.32811.60811.87512.01712.714.25214.03113.33513.22112.57312.75113.08113.37113.5214.28819.01218.77317.98117.85417.1217.32317.67818.01918.18419.0522.18421.92321.00620.86920.02520.26920.67621.04621.22422.22526.94426.65525.5725.42524.42524.68925.14625.61325.80126.98833.29433.00531.9231.77330.77531.03931.49631.96332.15433.33841.22940.9439.88539.70538.7138.98939.44639.90140.09441.27547.57947.2946.20546.05345.0645.33945.79646.25146.44947.62563.45263.16262.07861.9260.93261.21461.67162.12662.33263.5ORFS螺纹14.25214.03113.33513.22112.57312.75113.08113.37113.5214.28817.42717.18816.39616.27415.53515.74816.10416.43116.58917.46320.59920.36119.56819.44418.70718.92319.27919.60619.76620.63825.35725.09524.17824.03623.19523.44423.82524.22124.40725.430.11929.8328.74528.59827.627.86428.32128.78828.97930.16336.46736.17735.09334.94333.94734.21434.67135.13835.33136.51342.81742.52741.44341.2940.29740.56441.02141.48841.68642.86350.75450.46549.3849.22548.23548.51448.97149.42649.62750.8SAE螺纹15.83915.61814.92314.80314.16114.35114.68114.95815.1115.87526.94726.68325.74325.60824.7424.96825.37525.78325.96126.987其它美制螺纹9/16″×16UN14.25214.01313.22113.10112.3612.57312.92913.25613.41114.2887/8″×12UN22.18221.89220.80820.66819.66219.93920.39620.85121.03422.2252-1/4″×12UN57.10456.81555.7355.57554.58554.86455.32155.77655.97657.15注：UNC粗牙螺纹系列，UNF细牙螺纹系列，UNEF超细牙螺纹系列，UN不变螺距系列布锥管螺纹基本尺寸及公差(牙形角60o)NPT螺纹代号基面上的直径螺纹长度大径中径小径有效长度管端至基面长Z1/8″×2710.2729.5198.76674.572Z1/4″×1813.57212.44311.3149.55.080Z3/8″×1817.05515.92614.79710.56.096Z1/2″×1421.22319.77218.32113.58.028Z3/4″×1426.56825.11723.666148.611Z1″×11.533.22831.46129.69417.510.160Z1.1/4″×11.541.98540.21838.4511810.6882Z1.1/2″×11.548.05446.28744.52018.510.688Z2″×11.560.09258.32556.5581911.074公制螺纹基本尺寸及公差(牙形角60o)M基本直径螺纹代号大径中径小径M10X1109.3508.917M12X11211.35010.917M14X11413.35012.917M12X1.251211.18810.647M14X1.251413.18812.647M12X1.51211.02610.376M14X1.51413.02612.376M16X1.51615.02614.376M18X1.51817.02616.373M20X1.52019.02618.376M22X1.52221.02620.376M24X1.52423.02622.376M26X1.52625.02624.376M27X1.52726.02625.376M30X1.53029.02628.376M33X1.53332.02631.376M36X1.53635.02634.376M39X1.53938.02637.376M42X1.54241.02640.376M27X22725.70124.835M30X23028.70127.835M33X23331.70130.835M36X23634.70133.835M39X23937.70136.835M42X24240.70139.835M45X24543.70142.835M52X25250.70149.835M60X26058.70157.835M64X26462.70161.835M72X27270.70169.835内螺纹外螺纹公差等级公差等级6H7H6g中径公差小径公差中径公差小径公差中径公差大径公差+0.150+0.236+0.190+0.300-0.026-0.0260000-0.138-0.206+0.160+0.236+0.200+0.300-0.026-0.0260000-0.144-0.206+0.160+0.236+0.200+0.300-0.026-0.0260000-0.144-0.206+0.180+0.265+0.224+0.335-0.028-0.0280000-0.160-0.240+0.180+0.265+0.224+0.335-0.028-0.0280000-0.160-0.240+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.190+0.300+0.236+0.375-0.032-0.0320000-0.172-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.200+0.300+0.250+0.375-0.032-0.0320000-0.182-0.268+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.224+0.375+0.280+0.475-0.038-0.0380000-0.208-0.318+0.236+0.375+0.300+0.475-0.038-0.0380000-0.218-0.318+0.236+0.375+0.300+0.475-0.038-0.0380000-0.218-0.318+0.236+0.375+0.300+0.475-0.038-0.0380000-0.218-0.318+0.236+0.375+0.300+0.475-0.038-0.0380000-0.218-0.318355°圆锥管螺纹基本尺寸对照表最新下载-汇兴达55°圆锥管螺纹基本尺寸对照表最新下载-汇兴达55°圆锥管螺纹(BSPT)螺纹基本尺寸大径螺距每英寸中小径径外mm牙型高度代号R1/16R1/8R1/4R3/8mm英寸d=D1/17.76"231/89.7"281/413."1573/816."662mmp0.9070.9071.3371.337牙数tpi28281919螺d2H1纹=Dd236.7.15420.581618.9.150.581476611.12.40.8563014514.15.90.856806504R18.11/220.1.819.1.162146/"95514793231R24.33/426.1.825.1.162141/"441142794173R33.2.30.31.1"2491121.4791097791R3112.38.41.40.11/4091191.479910431/"542R4112.34.47.46.11/2091181.479803324/"4255R59.2.36.58.2"6141161.47920913556R75.2.373.21171.4792184097051/22.51"2/22684.R87.2.386.1.4793"8841193094052611131111R0.2.34".0311.551.4794091007211381363R5.2.35".4311.951.4795091407211631626R0.2.36".8311.351.47960918072聊城市鑫茂祥管业有限公司专业经营钢管规格：5mm*1mm—1020mm*200mm合金钢管、外径22mm-127mm冷轧无缝钢管、外径127mm-600mm，壁厚16mm-100mm，外径精度±0.5%,壁厚精度±5%热轧中厚壁无缝钢管、16Mn外径400—1600mm、壁厚20—60mm的大口径厚壁卷管，可定尺到16米及各种规格的无缝方管、异型无缝钢管等.常备钢管种类有:构造用无缝钢管、流体用无缝钢管、液压无缝钢管、电力用无缝钢管、石油输送用无缝钢管、化肥设备用无缝钢管、煤矿用无缝钢管、不锈钢无缝钢管、化工用无缝钢管、纺织机械用无缝钢管、汽车；水利用无缝钢管，精密无缝钢管、光亮无缝钢管、军工医疗用无缝钢管、管道用无缝钢管、支柱用无缝钢管、合金无缝管、高压无缝管、大口径直缝焊管等。适用于工程、煤矿、纺织、电力、锅炉、机械、军工等各个领域。公司以良好的信用、优质的产品、雄厚的实力、低廉的价钱享誉全国30多个省、市、自治区、直辖市及国外，产品深得用户依赖。6公司常年销售成都钢铁集团、冶钢集团、包头钢厂、宝钢集团、鞍钢集团、天津大无缝、西宁特钢厂、无锡钢厂、衡阳钢厂等各大钢厂生产的各种无缝钢管及合金管。主营材质：20#、35#、45#、20G、20A、40Mn2、45Mn2、27SiMn、40MnB、20MnVB、20Cr、30Cr、35Cr、40Cr、45Cr、50Cr、38CrSi、12CrMo、20CrMo、35CrMo、42CrMo、12CrMoV、12Cr1MoV、38CrMoAL、50CrV、20CrMnSi、30CrMnSi、35CrMnSi、20CrMnTi、30CrMnTi、12CrNi2、12CrNi3、12Cr2Ni4、40CrNiMoA、45CrNiMoVA、20G、20MnG、25MnG、12CrMoG、15CrMoG、12Cr2MoG、12Cr1MoVG、12Cr2MoWVTiB、12Cr3MoVSiTiB等实行 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 ：GB/T8162-99构造管、GB/T8163-99流体管、GB/T3087-99中低压锅炉管、GB/T5310-95高压锅炉管、GB/T6479-2000化肥专用管、27SiMn液压支架管、高压合金管、GB/T9948-85石油裂化管GB9948-88、地质钻探用管YB235-70、汽车半轴套管YB/T5035-96。现我公司有大量合金管、高压管、无缝方管、异型无缝钢管现货，将以优惠的价钱，批零兼营的方式，为您提供快捷优质的服务，欢迎新老客户前来洽谈、电议。管螺纹的基本尺寸表(2010-10-2515:57:35)转载▼标签：杂谈表（1）螺纹基本尺寸G1/2、ZG1/2(单位:mm)尺寸代每螺距p牙型圆弧半基面上的基本直径基准有效号25.4mm高度h径r≈大径（基中径小径距离螺纹类的牙准直径）d2=D2d1=D1长度数nd=D1/16280.9070.5810.1257.7237.1426.5614.06.51/8280.9070.5810.1259.7289.1478.5664.06.51/4191.3370.5860.18413.15712.30111.4456.09.73/8191.3370.5860.18416.66215.80614.9506.410.11/2141.8141.1620.24920.95519.79318.6318.213.23/4141.8141.1620.24926.44125.27924.1179.514.51112.3091.4790.31733.24931.77030.29110.416.81.1/4112.3091.4790.31741.91040.43138.95212.719.11.1/2112.3091.4790.31747.80346.32444.84512.719.12112.3091.4790.31759.61458.13556.65615.923.42.1/2112.3091.4790.31775.18473.70572.22617.526.73112.3091.4790.31787.88486.40584.92620.629.83.1/2112.3091.4790.317100.33098.85197.37222.231.44112.3091.4790.317113.030111.551110.07225.435.85112.3091.4790.317138.430136.951135.47228.640.16112.3091.4790.317163.830162.351160.87228.640.17锥管螺纹的基本尺寸表（3-28）1/2PT、1/2NPT表（2）螺纹基本尺寸(单位:mm)尺寸代每号25.4mm类的牙基面上的基本直径基准距离大径（基中径小径准直径）d2=D2d1=D1数nd=D1/16277.8957.1426.3894.0641/82710.2429.4898.7364.1021/41813.61612.48711.3585.7863/81817.05515.92614.7976.0961/21421.22319.77218.3218.1283/41426.56825.11723.6668.611111.533.22831.46129.69410.1601.1/411.541.98540.21838.45110.6681.1/211.548.05446.28744.52010.668211.560.09258.32556.55811.0742.1/2872.69970.15967.61917.3233888.60886.06883.52819.4563.1/28101.31698.77696.23620.85348113.973111.433108.89321.438螺纹标准的一种，按外形分圆柱、圆锥两种；按牙型角分55°、60°两种。螺纹中的1/4、1/2、1/8标记是指螺纹尺寸的直径，单位是英寸。一吋等于8分，1/4吋就是2分，如此类推。国外常用英制螺纹的代号、名称和标准号：B.S.W.标准惠氏粗牙系列，一般用途圆柱螺纹B.S.F.标准惠氏细牙系列，一般用途圆柱螺纹Whit.S附加的惠氏可选择系列，一般用途圆柱螺纹Whit惠氏牙型的非标准螺纹以上为英国标准BS84牙型角为55°的英制螺纹UN恒定螺距系列的统一螺纹UNC粗牙系列的统一螺纹UNF细牙系列的统一螺纹UNEF超细牙系列的统一螺纹UNS①特殊系列的统一螺纹UNR圆弧牙底恒定螺距系列的统一螺纹UNRC圆弧牙底粗牙系列统一螺纹8UNRF圆弧牙底细牙系列统一螺纹UNREF圆弧牙底超细牙系列统一螺纹UNRS圆弧牙底特殊系列统一螺纹以上为美国标准ANSIB1.1标准牙型(牙底是平的或随意倒圆的)的内、外螺纹圆弧牙底的UNR、UNRC、UNRF、UNREF、NRS只用于外螺纹而没有内螺纹NPT②一般用途的锥管螺纹NPSC管接头用直管螺纹NPTR导杆连接用锥管螺纹NPSM机械连接用直管螺纹NPSL锁紧螺母用直管螺纹NPSH软管连接用直管螺纹以上为美国标准ANSIB1.20.1牙型角为60°的英制管螺纹NPTF干密封标准型锥管螺纹美国标准ANSIB1.20.3Ⅰ型PTF-SAESHORT干密封短型锥管螺纹美国标准ANSIB1.20.3Ⅱ型NPSF干密封标准型燃油用直管内螺纹美国标准ANSIB1.20.3Ⅲ型NPS1干密封标准型一般用直管内螺纹美国标准ANSIB1.20.3Ⅳ型ACME③一般用途的梯形螺纹美国标准ANSIB1.5牙型角为29°的英制传动螺纹①尺寸和公差使用与标准系列相同的公式计算的标准系列之外的所有直径与螺距组合。②我国的60°圆锥管螺纹GB/T12716-1991与之等效。③ACME螺纹包括一般用途的和定心的两种配合的梯形螺纹，其中一般用途者与我国标准GB/T5796-1986 规定 关于下班后关闭电源的规定党章中关于入党时间的规定公务员考核规定下载规定办法文件下载宁波关于闷顶的规定 的梯形螺纹的性能相类同。螺距用每英寸的牙数来表示，如：每英寸11牙，则螺距＝25.4/11＝2.309mm螺纹如何区分英制和公制？默认分类2009-08-2422:03:14阅读1281评论0字号：大中小粗略判断的话好像英制的比公职的牙距大（同规格的）NPT，PT，G都是管螺纹．NPT是National(American)PipeThread的縮寫，屬於美国標准的60度锥管螺纹，用於北美地區．国家標准可查阅GB/T12716-1991PT是PipeThread的縮寫，是55度密封圓锥管螺纹，屬惠氏螺紋家族，多用於欧洲及英联邦国家．常用於水及煤气管行业，锥度規定为1:16．国家標准可查阅GB/T7306-2000G是55度非螺纹密封管螺纹，屬惠氏螺紋家族．标记为G代表圓柱螺紋．国家標准可查阅GB/T7307-2001另外螺纹中的1/4、1/2、1/8标记是指螺紋尺寸的直徑，單位是英吋．行內人通常用分來稱呼螺紋尺寸，一吋等於８分，1/4吋就是２分，如此類推好像就是管螺纹的统称(Guan)，55，60度的划分属于功能性的，俗称管圆。即螺纹由一圆柱面加工而成。ZG俗称管锥，即螺纹由一圆锥面加工而成，一般的水管接头都是这样的，老国标标注为Rc公制螺纹用螺距来表示，美英制螺纹用每英寸内的螺纹牙数来表示，这是它们最大的区别，9公制螺纹是60度等边牙型，英制螺纹是等腰55度牙型，美制螺纹60度。公制螺纹用公制单位，美英制螺纹用英制单位。管螺纹主要用来进行管道的连接，其内外螺纹的配合紧密，有直管与锥管两种。公称直径是指所连接的管道直径，显然螺纹大径比公称直径大。1/4，1/2，1/8是英制螺纹的公称直径，单位是英寸。英制螺纹标准规格表寸大径螺距每英寸牙数中径小径牙型高底孔直径牙型代号mmmmmm外螺纹WwtpiH1mmd=Dpd2=D2d31/16"BSW1.5870.423601.3151.0500.2701.153/32"BSW2.3810.529482.0411.7030.3381.901/8"BSW3.1750.635402.7682.3620.4062.505/32"BSW3.9690.793323.4592.9520.5073.203/16"BSW4.7621.058244.0843.4070.6773.707/32"BSW5.5561.058244.8784.2010.6774.501/4"BSW6.3501.270205.5374.7240.8135.105/16"BSW7.9381.411187.0346.1310.9046.503/8"BSW9.5251.588168.5097.4921.0177.907/16"BSW11.1131.814149.9518.7891.1629.201/2"BSW12.7002.1171211.3459.9901.35510.405/8"BSW15.8762.3091114.39712.9181.47913.403/4"BSW19.0512.5401017.42415.7981.62716.257/8"BSW22.2262.822920.41918.6111.80719.251"BSW25.4003.175823.36821.3352.03322.0011/8"BSW28.5763.629726.25323.9292.32424.5011/4"BSW31.7513.629729.42827.1042.32427.2513/8"BSW34.9264.233632.21529.5052.71130.2511/2"BSW38.1004.233635.39132.6802.71133.5015/8"BSW41.2775.080538.02434.7713.25335.5013/4"BSW44.4525.080541.19937.9463.25338.5017/8"BSW47.6275.64541/244.01240.3983.61441.252"BSW50.8025.64541/247.18743.5733.61444.5021/4"BSW57.1526.350453.08649.0204.06650.0021/2"BSW63.5026.350459.43655.3704.06656.0023/4"BSW69.8537.25731/265.20560.5584.64761.503"BSW76.2037.25731/271.55666.9094.64768.0031/4"BSW82.5537.81631/477.54872.5445.00573.7531/2"BSW88.9037.81631/483.89978.8945.00580.0033/4"BSW95.2548.467389.83284.4105.42285.504"BSW101.6048.467396.18290.7605.42292.001041/4"BSW107.9548.83527/8102.29796.6395.65798.0041/2"BSW114.3048.83527/8108.647102.9905.657104.2043/4"BSW120.6659.23723/4114.740108.6255.915110.005"BSW127.0059.23723/4121.090115.1765.915116.5051/4"BSW133.3559.67725/8127.159120.9636.196122.5051/2"BSW139.7059.67725/8133.509127.3136.196128.5053/4"BSW146.05510.16021/2139.549133.0436.506134.506"BSW152.40610.16021/2145.900139.3946.506141.00英制普通螺纹--细牙--BSF英制普通螺纹(惠氏螺纹)--细牙(BSW)名义尺寸大径螺距每英寸牙数中径小径牙型高底孔直径牙型代号mmmmmm外螺纹BSFtpiH1mmd=Dpd2=D2d33/16BSF4.7630.794324.2553.7470.5084.007/32BSF5.5560.907284.9754.3940.5814.601/4BSF6.3500.977265.7255.1000.6255.309/32BSF7.1420.977266.5185.8930.6256.105/16BSF7.9381.156227.1996.4590.7396.803/8BSF9.5251.27208.7127.8990.8138.307/16BSF11.1131.4111810.2099.3040.9049.701/2BSF12.7001.5881611.68410.6681.01711.109/16BSF14.2881.5881613.27212.2561.01712.705/8BSF15.8751.8141414.71213.5491.16214.0011/16BSF17.4631.8141416.30015.1371.16215.503/4BSF19.0502.1171217.69316.3361.35516.7513/16BSF20.6382.1171219.28117.9241.35518.257/8BSF22.2252.3091120.74719.2691.47919.751BSF25.4002.541023.77422.1481.62722.7511/8BSF28.5752.822926.76924.9631.80726.5011/4BSF31.7502.822929.94428.1381.80728.7513/8BSF34.9253.175832.89330.8612.03331.5011/2BSF38.1003.175836.06834.0362.03334.5015/8BSF41.2753.175839.24337.2112.03338.0013/4BSF44.4503.629742.12639.8022.32440.502BSF50.8003.629748.47646.1522.32447.0021/4BSF57.1504.234654.44051.7302.71153.001121/2BSF63.5004.234660.79058.0802.71159.0023/4BSF69.8504.234667.14064.4302.711-3BSF76.2005.08572.94669.6923.253-31/4BSF82.5505.08579.29676.0423.253-31/2BSF88.9005.64541/285.28581.6703.614-33/4BSF95.2505.64541/291.63588.0203.614-4BSF101.6005.64541/297.98594.3703.614-41/4BSF107.9506.354103.88699.8224.066-螺纹标记的标注当螺纹精度要求较高时，除标注螺纹代号外，还应标注螺纹公差带代号和螺纹旋合长度。螺纹标记的标注格式为：螺纹代号—螺纹公差带代号(中径、顶径)—旋合长度有关标注内容的说明：1)公差带代号由数字加字母表示(内螺纹用大写字母，外螺纹用小写字母)，如7H、6g等，应特别指出，7H，6g等代表螺纹公差，而H7，g6代表圆柱体公差代号。旋合长度规定为短(用S表示)、中(用N表示)、长(用L表示)三种。一般情况下，不标注螺纹旋合长度，其螺纹公差带按中等旋合长度(N)确定。必要时，可加注旋合长度代号S或L，如“M20-5g6g－L”。特殊需要时，可注明旋合长度的数值，如“M20-5g6g－30”。相关链接美英制螺纹用英制单位螺纹标准,螺纹标准手册螺纹的结构英制螺纹尺寸,英制螺纹尺寸表英制螺纹规格,英制螺纹规格表英制管螺纹（55°）英制螺纹标注方法12