UN_美制螺纹及尺寸表

美制螺纹参数大全
1、螺纹种类
（1）美制直插螺纹，主要包括：美制单螺纹UNC/UNF、双螺纹UNS、
美制外螺纹UNEF、美制内螺纹UN-2B；
（2）美制特殊螺纹，包括：美制特定角度牙螺纹、美制畸变牙螺纹、美制法兰螺纹（矩形牙、圆锥牙和接头）、美制外螺纹UNJ、美制攻牙螺
纹UNC-2A、美制攻牙螺纹UNF-2A、美制沉头螺纹UNRC和美制沉头螺纹UNRF；
（3）美制键槽螺纹，包括：美制原头螺纹UNJF、美制梯形螺纹UNC-
3A、美制六角螺纹UMS-3A、美制方形螺纹USS-3A；
（4）美制螺母螺纹，包括：美制内螺纹UN-2M、美制外螺纹UNS-2M。

2、螺纹细微尺寸参数
（1）螺纹基本尺寸参数：螺纹名称、螺纹基径、螺距、牙型、牙数、类型；
（2）螺纹细微尺寸参数：螺纹直径、根部牙齿形状和大小、锥度、
误差、螺距和牙顶形状和大小等；
（3）螺纹型腔尺寸参数：型腔螺距、型腔大小、误差、型腔圆度和
横档尺寸等。

3、螺纹位置参数
（1）螺纹位形参数：螺纹位形中心、六角锥螺纹位形、矩形锥螺纹
位形及对称多边形螺纹位形等；。

螺纹小径螺纹外径MaxMin Max Min Max Min Max Min Max Min 1-64UNC640.2360.3972A 1.83896 1.74244 1.58242 1.53162 1.366522B 1.42494 1.58242 1.59766 1.6637 1.8542 1.3973A1.8542 1.75768 1.59766 1.55956 1.381763B 1.42494 1.58242 1.59766 1.64592 1.8542 1.3971-72UNF720.210.3532A 1.83896 1.75006 1.61036 1.5621 1.419862B 1.4732 1.6129 1.6256 1.6891 1.8542 1.51133A1.8542 1.7653 1.6256 1.59004 1.43513B 1.4732 1.6129 1.6256 1.67386 1.8542 1.51132-56UNC560.2710.4542A 2.16916 2.06502 1.87452 1.82118 1.630682B 1.69418 1.87198 1.88976 1.96088 2.1844 1.70183A2.1844 2.08026 1.88976 1.84912 1.645923B 1.69418 1.87198 1.88976 1.9431 2.1844 1.70182-64UNF640.2360.3972A 2.16916 2.07264 1.91262 1.86182 1.696722B 1.75514 1.91262 1.92786 1.99644 2.1844 1.7783A2.1844 2.08788 1.92786 1.88976 1.711963B 1.75514 1.91262 1.92786 1.97866 2.1844 1.7783-48UNC480.3150.5292A 2.49682 2.38252 2.15392 2.0955 1.864362B 1.94056 2.1463 2.1717 2.2479 2.5146 1.99393A2.5146 2.4003 2.1717 2.12852 1.882143B 1.94056 2.1463 2.1717 2.22758 2.5146 1.99393-56UNF560.2710.4542A 2.49682 2.39268 2.20218 2.1463 1.958342B 2.02438 2.1971 2.21996 2.29108 2.5146 2.05743A2.5146 2.41046 2.21996 2.17932 1.976123B 2.02438 2.1971 2.21996 2.2733 2.5146 2.05744-40UNC400.3780.6352A 2.82448 2.69494 2.413 2.3495 2.067562B 2.15646 2.38506 2.43332 2.51714 2.8448 2.18443A2.8448 2.71526 2.43332 2.38506 2.087883B 2.15646 2.38506 2.43332 2.49428 2.8448 2.18444-48UNF480.3150.5292A 2.82702 2.71272 2.48412 2.42316 2.194562B 2.27076 2.45872 2.5019 2.58064 2.8448 2.26063A2.8448 2.7305 2.5019 2.45618 2.212343B 2.27076 2.45872 2.5019 2.56032 2.8448 2.26065-40UNC400.3780.6352A 3.15468 3.02514 2.7432 2.67716 2.397762B 2.48666 2.69748 2.76352 2.84734 3.175 2.52733A3.175 3.04546 2.76352 2.71526 2.418083B 2.48666 2.69748 2.76352 2.82702 3.175 2.52735-44UNF440.3440.5772A 3.15722 3.0353 2.7813 2.7178 2.468882B 2.55016 2.74066 2.79908 2.88036 3.175 2.57813A3.175 3.05308 2.79908 2.75082 2.486663B 2.55016 2.74066 2.54508 2.86004 3.175 2.57816-32UNC320.4720.7942A 3.48488 3.33248 2.96926 2.89814 2.542B 2.6416 2.8956 2.98958 3.08356 3.5052 2.70513A3.5052 3.3528 2.98958 2.93624 2.560323B 2.6416 2.8956 2.98958 3.05816 3.5052 2.70516-40UNF400.3780.6352A 3.48488 3.35534 3.0734 3.00736 2.727962B 2.8194 3.0226 3.09372 3.18008 3.5052 2.87023A3.50523.375663.093723.042922.748283B2.81943.012443.093723.157223.50522.8702公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径0.073（#1）1.8540.086(#2)2.1840.099(3#)2.515螺纹中经公差代号螺纹小径螺纹中径0.112(#4)2.8450.125(#5)3.1750.138(#6）3.505螺纹小径螺纹外径MaxMin Max Min Max Min Max Min Max Min 公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径螺纹中经公差代号螺纹小径螺纹中径8-32UNC320.4720.7842A 4.14274 3.99034 3.62712 3.55346 3.197862B 3.302 3.5306 3.64998 3.7465 4.1656 3.45443A4.1656 4.0132 3.64998 3.5941 3.220723B 3.302 3.52806 3.64998 3.7211 4.1656 3.45448-36UNF360.4210.7062A 4.14528 4.00558 3.68808 3.61696 3.304542B 3.4036 3.6068 3.7084 3.79984 4.1656 3.45443A4.1656 4.0259 3.7084 3.65506 3.324863B 3.4036 3.59664 3.7084 3.77698 4.1656 3.454410-24UNC240.631.0582A 4.8006 4.61772 4.11226 4.02844 3.540762B 3.683 3.9624 4.13766 4.24688 4.826 3.73383A4.826 4.64312 4.13766 4.07416 3.566163B 3.683 3.9497 4.13766 4.21894 4.826 3.733810-28UNS 280.540.9072A 4.8006 4.6355 4.21132 4.1275 3.718562B 3.8354 4.064 4.23672 4.34594 4.826 3.860810-32UNF320.4720.7842A 4.80314 4.65074 4.28752 4.21132 3.858262B 3.9624 4.1656 4.31038 4.40944 4.826 3.98783A 4.826 4.6736 4.31038 4.25196 3.881123B 3.9624 4.16814 4.31038 4.38404 4.826 3.987810-36UNS 360.4210.7062A 4.80314 4.66344 4.34594 4.26974 3.96242B 4.064 4.2164 4.3688 4.46786 4.826 4.038610-40UNS 400.3780.6352A 4.80314 4.6736 4.39166 4.318 4.043682B 4.1402 4.2926 4.41452 4.5085 4.826 4.089410-48UNS 480.3150.5292A 4.80568 4.69138 4.46278 4.39674 4.175762B 4.2418 4.3688 4.4831 4.56946 4.826 4.216410-56UNS 560.2710.4542A 4.80822 4.70408 4.51358 4.45008 4.269742B 4.3434 4.445 4.53136 4.61264 4.826 4.305312-24UNC240.631.0582A 5.461 5.27812 4.77266 4.6863 4.201162B 4.3434 4.5974 4.79806 4.90982 5.4864 4.49583A5.4864 5.30352 4.79806 4.73202 4.226563B 4.3434 4.58978 4.79806 4.88188 5.4864 4.495812-28UNF280.540.9072A 5.461 5.2959 4.87172 4.79044 4.378962B 4.4958 4.7244 4.89712 5.0038 5.4864 4.5723A5.4864 5.3213 4.89712 4.83616 4.404363B 4.4958 4.71678 4.89712 4.97586 5.4864 4.57212-32UNEF320.4720.7842A 5.46354 5.31114 4.94792 4.86918 4.518662B 4.6228 4.826 4.97078 5.07492 5.4864 4.5723A5.4864 5.334 4.97078 4.90982 4.541523B 4.6228 4.8133 4.97078 5.04952 5.4864 4.57212-36UNS 360.4210.7062A 5.46354 5.32384 5.00634 4.93014 4.879342B 4.7244 4.8768 5.0292 5.12826 5.4864 4.800612-40UNS 400.3780.6352A 5.46354 5.334 5.05206 4.9784 4.66092B 4.8006 4.953 5.07492 5.1689 5.4864 4.851412-48UNS 480.3150.5292A 5.46608 5.35178 5.12318 5.05714 4.836162B 4.9022 5.0292 5.1435 5.22986 5.4864 4.978412-56UNS560.2710.4542A5.468625.364485.173985.110484.930142B5.00385.10545.191765.273045.48644.97840.164（#8）4.1660.19（#10）4.8260.216（#12）0.486螺纹小径螺纹外径MaxMin Max Min Max Min Max Min Max Min 公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径螺纹中经公差代号螺纹小径螺纹中径1/4-20UNC200.7561.271A 6.32206 6.01218 5.49656 5.35432 4.810761B 4.9784 5.2578 5.5245 5.70992 6.35 5.10542A 6.32206 6.11632 5.49656 5.40258 4.810762B 4.9784 5.2578 5.5245 5.64896 6.35 5.10543A6.35 6.14426 5.5245 5.45338 4.83873B 4.9784 5.25018 5.5245 5.61594 6.35 5.10541/4-24UNS 240.63 1.0582A 6.32206 6.13918 5.63372 5.53974 5.062222B 5.207 5.461 5.66166 5.78358 6.35 5.30861/4-27UNS 270.560.9412A 6.3246 6.15442 5.71246 5.62356 5.204462B 5.334 5.5626 5.73786 5.85216 6.35 5.41021/4-28UNF280.540.9071A 6.3246 6.07568 5.73532 5.60832 5.242561B 5.3594 5.588 5.76072 5.92582 6.35 5.41022A 6.3246 6.1595 5.73532 5.6515 5.242562B 5.3594 5.588 6.82752 5.86994 6.35 5.41023A 6.35 6.1849 5.76072 5.69722 5.267963B 5.3594 5.5626 6.82752 5.842 6.35 5.41021/4-32UNEF320.4720.7842A 6.3246 6.1722 5.80898 5.7277 5.379722B 5.4864 5.6896 5.83438 5.94106 6.35 5.554983A6.35 5.6896 5.83438 5.77342 5.405123B 5.4864 5.66166 5.83438 5.91312 6.35 5.554981/4-36UNS 360.4210.7062A 6.32714 6.18744 5.86994 5.7912 5.488942B 5.588 5.7404 5.8928 5.9944 6.35 5.61341/4-40UNS 400.3780.6352A 6.32714 6.1976 5.91566 5.842 5.570222B 5.6642 5.8166 5.93852 6.03504 6.35 5.79121/4-48UNS 480.3150.5292A 6.32968 6.21538 5.98678 5.9182 5.697222B 5.7658 5.8928 6.0071 6.09854 6.35 5.79121/4-56UNS 560.2710.5452A 6.32968 6.22554 6.03504 5.969 5.79122B 5.8674 5.969 6.05536 6.13918 6.35 5.94365/16-18UNC180.8411.4111A 7.907027.57428 6.99008 6.83514 6.228081B 6.4008 6.7317.020567.221227.9375 6.52782A 7.907027.68604 6.99008 6.88848 6.228082B 6.4008 6.7317.020567.155187.9375 6.52783A7.93757.716527.02056 6.94436 6.258563B 6.4008 6.68027.020567.119627.9375 6.52785/16-20UN200.7561.272A 7.907027.701287.08152 6.97992 6.395722B 6.5532 6.8587.1127.244087.9375 6.746243A7.93757.731767.1127.0358 6.42623B 6.5532 6.80727.1127.211067.9375 6.746245/16-24240.631.0581A 79095.67.635247.221227.08152 6.649721B 6.78187.03587.249167.42957.9375 6.90882A7.909567.726687.221227.12724 6.649722B 6.78187.03587.249167.371087.9375 6.90883A7.93757.754627.249167.18058 6.677663B 6.7818 6.995167.249167.34067.9375 6.90885/8-27UNS 270.560.9412A 7.91217.741927.299967.21106 6.791962B 6.90887.13747.249167.439667.93757.03585/8-28UN280.540.9072A7.91217.7477.322827.236466.830062B6.95967.16287.348227.459987.93757.03580.25"6.350.3125"7.9375螺纹小径螺纹外径MaxMin Max Min Max Min Max Min Max Min 公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径螺纹中经公差代号螺纹小径螺纹中径3A7.93757.77247.348227.28218 6.855463B 6.95967.129787.348227.432047.93757.03585/8-32UNEF320.4720.7842A 7.91217.75977.31527.3152 6.967222B 7.08667.26447.421887.528567.93757.142483A7.93757.78517.360927.36092 6.992623B 7.08667.231387.421887.500627.93757.142485/8-36UNS 360.4210.7062A 7.914647.774947.45744 5.32137.07392B 7.16287.34067.48037.58197.93757.142485/8-40UNS 400.3780.6352A 7.914647.78517.503167.42957.157722B 7.2397.39147.526027.622547.93757.3665/8-48UNS 40.3120.3150.5292A 7.917187.802887.574287.50577.287262B 7.3667.4937.59467.686047.93757.3663/8-16UNC180.8411.4111A 9.491989.13138.460748.295647.599681B 7.79788.15348.493768.709669.5257.93752A 9.491989.253228.460748.348987.599682B 7.79788.15348.493768.638549.5257.93753A9.5259.286248.493768.409947.63273B 7.79788.082288.493768.602989.5257.93753/8-18UNS 180.841 1.4112A 9.491989.2718.575048.465827.813042B 8.0018.33128.608068.75039.5258.02643/8-20UN200.7561.272A 9.494529.288788.669028.564887.983222B 8.15348.43288.69958.836669.5258.333743A9.5259.319268.69958.620768.01373B 8.15348.374388.69958.69959.5258.333743/8-24UNF240.631.0581A 9.497069.222748.808728.663948.237221B 8.3828.6368.836668.836669.5258.43282A 9.497069.314188.808728.71228.237222B 8.3828.6368.836668.961129.5258.43283A 9.5259.342128.836668.7638.265163B 8.3829.44888.836668.5130649.5258.43283/8-27UNS 270.560.9412A 9.497069.326888.884928.793488.376922B 8.5098.73768.912869.032249.5258.61063/8-28UN280.540.9072A 9.497069.331968.907788.816348.415022B 8.53448.7638.935729.052569.5258.61063A9.5259.35998.935728.867148.442963B 8.53448.702048.935729.024629.5258.61063/8-32UNEF320.4720.7842A 8.569969.34728.983988.897628.554722B 8.66148.86469.009389.121149.5258.83923A9.5259.37269.009388.945888.580123B 8.66148.811269.009389.09329.5258.83923/8-36UNS 360.4210.7062A 9.49969.35999.04248.961128.658862B 8.7638.94089.06789.174489.5258.83923/8-40UNC400.3780.6352A 9.502149.37269.090669.011928.745222B 8.83928.99169.113529.215129.5258.83920.39" 9.9060.390-27UNS270.560.9412A9.878069.707889.265929.174488.757922B8.899.11869.293869.413249.9068.83920.325"8.255螺纹小径螺纹外径MaxMinMax Min Max Min Max Min Max Min 公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径螺纹中经公差代号螺纹小径螺纹中径7/16-14UNC141.0811.8141A 11.0769410.683249.898389.718048.917941B 9.1449.55049.9339410.1676211.11259.34722A 11.0769410.815329.898389.7798.917942B 9.1449.55049.9339410.0888811.11259.34723A11.112510.850889.933949.845048.95353B 9.1449.441189.9339410.0507811.11259.34727/16-16UNS160.861.5882A 11.0769410.8381810.04579.928869.184642B 9.3989.753610.0812610.2311211.11259.57583A11.0667810.8737410.081269.99499.22023B 9.3989.65210.0812610.1955611.11259.57587/16-18UNS 180.841 1.4112A 11.0794810.858510.1625410.053329.400542B 9.57589.90610.1955610.337811.11259.80447/16-20UNF200.7561.271A 11.0794810.769610.9397810.09659.568181B 9.728210.03310.28710.4927411.066789.921242A 11.0794810.8737410.9397810.14739.568182B 9.728210.03310.28710.4241611.066789.921243A11.112510.9067610.312410.208269.60123B 9.72829.9466410.28710.3911411.066789.921247/16-24UNS 240.63 1.0582A 11.0845610.9016810.3962210.29979.824722B 9.956810.210810.4241610.5486211.0667810.08387/16-27UNS 270.560.9412A 11.0845610.9143810.4724210.380989.964422B 10.083810.312410.5003610.6197411.112510.26167/16-28UNEF280.540.9072A 11.0845610.9194610.4952810.4038410.002522B 10.134610.337810.5232210.6400611.112510.26163A11.112510.94748.67232210.4546410.030463B 10.134611.4579410.5232210.6121211.112510.26167/16-32UN320.4720.7842A 11.087110.934710.5714810.4851210.142222B 10.261610.439410.5968810.7086411.112510.26163A11.112510.960110.5968810.5333810.167623B 10.261610.3987610.5968810.680711.112510.26161/2-13UNC131.1631.9541A 12.661912.2478811.391911.2039410.259061B 10.591811.023611.4311.6763812.710.716262A 12.661912.3850411.391911.264910.335262B 10.591811.023611.4311.595112.710.716263A12.712.4231411.4311.3360210.373363B 10.591810.8813611.4311.5519212.710.716261/2-12UNS121.262.1172A 12.6593612.369811.2852211.1480610.139682B 10.41410.871211.3258611.5036612.710.716263A12.712.4104411.3258611.2242610.180323B 10.41410.7264211.3258611.4579412.710.716261/2-14UNS 14 1.081 1.8142A 12.661912.4002811.4833411.3563410.50292B 10.744211.125211.5214411.6865412.710.716261/2-16UNS160.861.5882A 12.6644412.4256811.633211.5138210.772142B 10.972811.328411.6687611.823712.711.11253A13.20812.4612411.6687611.5798610.80773B 10.972811.2242611.6687611.785612.711.11251/2-18UNS180.8411.4112A12.6669812.44611.7500411.6382810.988042B11.17611.506211.7830611.9303812.711.11250.4375"11.110.5"螺纹小径螺纹外径MaxMin MaxMinMaxMin Max Min Max Min 公称直径螺纹规格牙数牙高螺距公差代号螺纹外径钻孔直径螺纹中经公差代号螺纹小径螺纹中径1/2-20UNF200.7561.271A 12.6669812.357111.8414811.6789212.527281B 11.328411.607811.874512.0878612.711.508742A 12.6669812.4612411.8414811.7322612.527282B 11.328411.607811.874512.0167412.711.508743A12.712.4942611.874511.7932211.191243B 11.328411.5239811.874511.9811812.711.508741/2-24UNS 240.63 1.0582A 12.6695212.4866411.9811811.8821211.409682B 11.55711.81112.0116612.141212.711.508741/2-27UNS 270.560.9412A 12.6720612.5018812.0599211.9659411.551922B 11.68411.912612.0878612.2097812.711.904981/2-28UNEF280.540.9072A 12.6720612.5069612.0827811.988811.590022B 11.709411.93811.93812.2326412.711.904983A12.712.534912.1107212.039611.617963B 11.709411.8770412.1107212.2021612.711.904981/2-32UN320.4720.7842A 12.674612.522212.1589812.0700811.729722B 11.836412.039612.1843812.2986812.711.904983A12.712.547612.1843812.1183411.755123B 11.836411.9862612.1843812.2707412.711.904989/16-12UNC121.262.1171A 14.2468613.8099812.8727212.674611.727181B 11.988812.44612.9133613.1724414.287512.303762A 14.2468613.957312.8727212.7406411.727182B 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17.894318.427718.986519.278620.637518.254983A20.637520.3098419.0322218.9204617.520923B 17.894318.427718.986519.1820820.637518.2549813/16-12UN121.262.1172A 20.5943220.3047619.2201819.0804818.201642B 18.338818.79619.2633619.4462420.637518.653763A20.637520.3479419.2633619.1592218.117823B 18.338818.6156619.2633619.4005220.637518.6537613/16-16UN160.861.5882A 20.599420.3606419.5681619.443718.70712B 18.92319.278619.6062619.7662820.637519.053A20.637520.3987419.6062619.5148218.74523B 18.92319.1338219.6062619.7256420.637519.0513/16-20UNEF200.7561.272A 20.6044820.3987419.7789819.6672219.093182B 19.253219.55819.81219.9567820.637519.446243A20.637520.4317619.81219.7281819.12623B 19.253219.4614819.81219.9212220.637519.4462413/16-28UN280.540.9072A 20.6070220.4419220.0177419.9212219.524982B 19.659619.862820.0482220.1752220.637519.842483A20.637520.421620.0482219.9745619.555463B 19.659619.8145420.0482220.142220.637519.8424813/16-32UN320.4720.7842A 20.6095620.4571620.0939420.002519.664682B 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20.269220.675621.0464421.2242422.22520.63753A22.22521.9633821.0464420.942320.0663B 20.269220.4927221.0464421.1810622.22520.63757/8-16UN160.861.5882A 22.186921.9481421.1556621.031220.0662B 20.497820.853421.1937621.3537822.22520.63753A22.22521.9862421.1937621.1023220.33273B 20.497820.7213221.1937621.3131422.22520.63757/8-18UNS 180.841 1.4112A 22.1894421.9684621.272521.1556620.51052B 20.70121.031221.3080621.4604622.22521.033747/8-20UNEF200.7561.272A 22.1919821.9862421.3664821.2547220.680682B 20.853421.132821.399521.5442822.22521.033743A22.22522.0192621.399521.3156820.71373B 20.853421.0489821.399521.5087222.22521.033747/8-24UNS 240.63 1.0582A 22.1945222.0116421.5061821.4020420.934682B 21.08221.33621.5366621.6712822.22521.033747/8-27UNS 270.560.9412A 22.1945222.0243421.5823821.4833221.074382B 21.20921.437621.6128621.742422.22521.429987/8-28UN280.540.9072A 22.1945222.0294221.6052421.5087221.112482B 21.234421.46321.6357221.7627222.22521.429983A22.22522.059921.6357221.5620621.142963B 21.234421.4020421.6357221.729722.22521.429987/8-32UN320.4720.7842A 22.1970622.0446621.6814421.5921.252182B 21.361421.564621.7093821.8287622.22521.429983A22.22522.072621.7093821.640821.280123B 21.361421.5112621.7093821.8008222.22521.4299815/16-9UNC91.682.8222A 23.7693223.4162621.9354421.7754220.40892B 22.136121.348721.9786222.186923.812521.033743A23.812523.4594421.9786221.8592420.452083B 22.136121.0972421.9786222.1335623.812521.0337415/16-12UN121.262.1172A 23.7693223.4797622.3951822.250421.249642B 21.513821.97122.4383622.6263223.812521.828763A23.812523.5229422.4383622.3342221.292823B 21.513821.780522.4383622.5780623.812521.8287615/16-16UN160.861.5882A 23.774423.5356422.7431622.6161621.88212B 22.09822.453622.7812622.9463623.812524.7653A23.812523.5737422.7812622.6872821.92023B 22.09822.3088222.7812622.9057223.812522.22515/16-20UNEF200.7561.272A 23.7769423.571222.9514422.8371422.265642B 22.428222.73322.98723.1368623.812522.2253A23.812523.6067622.98722.9006422.30123B 22.428222.6364822.98723.0987623.812522.22515/16-28UN280.540.9072A 23.7820223.6169223.1927423.0911422.699982B 22.834623.037823.2232223.355323.812523.017483A23.812523.647423.2232223.1470222.730463B 22.834622.9895423.2232223.3222823.812523.0174815/16-32UN320.4720.7842A23.7845623.6321623.2689423.1724222.839682B22.961623.139423.2968823.4213423.812523.017480.875"22.2250.9375"23.813。

螺纹规格-美制、英制、公制公制/美制/英制螺纹对照表给大家分享一下 f_a_NpX?,_A型美制螺纹（UNF）常用规格 _,!3_,oiq 牙型角60外螺纹内螺纹 ___UXx^Y2-4 9/16"-19牙14.28 13.08 8j,M4D*&_-6 11/16''-16 17.46 16.1 {lh _szc-8 13/16''-16 20.64 19.28 cM__iO|N@1 -10 1''-14 25.40 23.57 h |t_B __-12 1(3/16)''-12 30.00 28.32 )Al{84<(} -16 1(7/16)''-12 36.51 34.67 Ys$3}LA{-20 1(11/16)''-12 42.86 41.02 SW_7V7_S*Q z{Akh02V@C型JIC37度美制UNF螺纹常用规格 (" G'W牙型角60-4 7/16”-20 11.11 10.03 _e~_xb_Qr-5 1/2”-20 12.70 11.32-6 9/16”-18 14.28 13.08 NH'YgL6*-8 3/4”-16 19.00 17.68 lxv;6_S!J-10 7/8”-14 22.22 20.68 P_|J_&?KbC-12 1(1/16)"-12 26.98 25.15 Ki;_ __ ++ -16 1(5/16)"-12 33.33 31.5 ZF_!BkZ Uo-20 1(5/8)"-12 41.28 39.44 _LX_+_c_Z-24 1(7/8)"-12 47.62 45.8 iDP___@c_g-32 2(1/2)"-12 63.5 61.67 j/5_1_j@^L\e_w;h4_y英制圆柱管螺纹（BSPP）常用规格 dApgz_U@_; 牙型角55-4 1/4”-19 13.157 11.55 |,hu_r8BE\-6 3/8”-19 16.662 14.95 @"%@;>W<t-8 1/2”-14 20.955 18.63 F_)$7 ?')p-12 3/4”-14 26.441 24.11 Q} &f3?_-16 1”-11 33.249 30.29 YZ__@pwhZ<-20 1(1/4)''-11 41.91 38.95 SmU'a_o.\<v{UpdB"_]5英制圆锥管螺纹（BSPT）常用规格 b_sDck <lI 牙型角55基面大径基准距离 A4<_q__07#1/4”-19 13.157 6 _}@E_K'k_3/8”-19 16.662 6.4 .gy5/.SZ1/2”-14 20.955 8.2 R0?/'_gt_3/4”-14 26.441 9.5 _aF4L{_'qK1”-11 33.249 10.4 __Q,Y do_D1(1/4)''-11 41.91 12.7 i_'9mo0bmO@;ir e_^C X "TaT"(1__ G_#_ 美制圆锥管螺纹（NPT） __9_mJ___f 牙型角601/8”-27 10.24 4 3_x_VYo_$g1/4”-18 13.60 4 L8___|v.?J3/8”-18 17.04 4.32 __[ijs_K_1/2”-14 21.22 4.48 _"Lx Hg]')3/4”-14 26.57 4.75 GIry_h_+&a1”-11(1/2)” 33.22 4.6 qBc!A~8K4'1(1/4)”-11.5 41.96 4.83螺纹的一般知识第一章国标螺纹的一般知识一. 螺纹的分类1. 螺纹分内螺纹和外螺纹两种；2. 按牙形分可分为：1）三角形螺纹 2）梯形螺纹 3）矩形螺纹 4）锯齿形螺纹；3. 按线数分单头螺纹和多头螺纹；4. 按旋入方向分左旋螺纹和右旋螺纹两种, 右旋不标注，左旋加LH，如M24×1.5LH；5. 按用途不同分有：米制普通螺纹、用螺纹密封的管螺纹、非螺纹密封的管螺纹、60°圆锥管螺纹、米制锥螺纹等二. 米制普通螺纹1. 米制普通螺纹用大写M表示，牙型角2α=60°（α表示牙型半角）；2. 米制普通螺纹按螺距分粗牙普通螺纹和细牙普通螺纹两种；2.1. 粗牙普通螺纹标记一般不标明螺距，如M20表示粗牙螺纹；细牙螺纹标记必须标明螺距，如M30×1.5表示细牙螺纹、其中螺距为1.5。

美标内螺纹孔径d=25.4*公称直径D-25.4/牙数
例如：UNC1/2“美标粗牙螺纹，螺距一寸13牙
d=25.4*1/2-25.4/13=12.7-1.95=10.75（mm）
即：该内螺纹的孔径为10.75毫米。

如美制3/8-24 前面的是公称直径，也就是大径。

后面的是螺距。

代表的是每表英寸多少牙。

那么大径就等于3/8（公制尺寸是3/8 ×25.4) 小径等于3/8 ×25.4 - 25.4/24 ，内孔直径约等于小径。

英制螺纹小径等于D1=D-1.280654P ——内孔直径
中径等于D2=D-0.640327P
D就是公称直径。

P螺距。

这两个的算法与美制相同。

所以也就是说公制与美制就是公称直径减去螺距。

但管螺纹，英制螺纹不是。

另外，管螺纹没有标准算法。

需查相关手册才能得到。

如《螺纹实用手册》（机械工业出版社）
追问
那英制螺纹应该是怎么样呀
回答
英制螺纹小径等于D1=D-1.280654P ——内孔直径
中径等于D2=D-0.640327P
"D:就是公称直径。

"P"螺距。

D与P的算法与美制相同。