美制螺纹(统一对照表)直径螺距组合表(0~4)
美制螺纹标准
美制螺纹美制标准螺纹（也称统一制螺纹）量规用于检测螺纹的内外牙，螺纹牙形角60度，由外径、每英寸牙数、精度组合表示，如1/4-20UNC-2B，表示1/4英寸外径、每英寸20牙、2B精度内螺纹塞规，若是左旋旋向，应加LH表示。
美制内螺纹默认精度为2B，3B紧密级亦可提供，此外美制外螺纹的默认精度为2A，紧密级精度为3A，订货时注明精度，不提供精度按默认精度提供。
美制螺纹系列众多，美制粗牙（UNC）、美制细牙（UNF）、美制特细牙（UNEF）、美制不变螺距螺纹（UN）、美制特殊螺纹（UNS）。
还有一些美制牙将另外描叙。
第二次世界大战中，盟军的武器和装备所使用的螺纹主要有两种：一种是英国的惠氏螺纹（BSW、BSF）；另一种是美国国家螺纹（UNC、UNF、UNEF、UN、UNS）；由于两种螺纹的标准不统一，给盟军造成了严重的经济损失和人员伤亡。
二战结束以后，美国、英国和加拿大等盟国马上制定了统一的螺纹标准，由于当时美国的经济实力和军事实力在盟军中占主导地位，统一制螺纹主要是依据美国国家螺纹标准制定的，因此，在紧固螺纹领域，统一制螺纹开始挤占英国惠氏螺纹的使用市场，惠氏螺纹的圆弧牙顶和牙底牙型，叫英国吃了苦果；另外，澳大利亚、马来西亚、印度尼西亚、阿根廷、智利、比利时、匈牙利、意大利、瑞典、捷克等各国家也制定了惠氏螺纹国家标准。
现在世界各国使用惠氏螺纹（BSW、BSF）的国家在不断减少，取而代之的是统一制螺纹（UNC、UNF、UNEF、UN、UNS）。
美制螺纹（UNC、UNF、UNEF、UN、UNS）相关规格：NO：0-80UNF、NO：1-64UNC、NO：2-56UNC、NO：3-48UNC、NO：4-40UNC、NO：4-48UNF、NO：5-40UNC、NO：6-32UNC、NO：6-40UNF、NO：8-32UNC、NO：8-36UNC、NO：10-24UNC、NO：10-32UNF、NO：10-40UNS、NO：12-24UNC、NO：12-28UNF、NO：12-36UNS、1/4-20UNC、1/4-24UNS、1/4-28UNF、1/4-32UNEF、5/16-18UNC、5/16-20UN、5/16-24UNF、5/16-27UNS、5/16-32UNEF、3/8-16UNC、3/8-20UN、3/8-24UNF、3/8-32UNEF、7/16-14UNC、7/16-20UNF、7/16-24UNS、7/16-28UNEF、1/2-12UNS、1/2-13UNC、1/2-16UN、1/2-20UNF、1/2-28UNEF、9/16-12UNC、9/16-18UNF、9/16-24UNEF、5/8-11UNC、5/8-18UNF、5/8-24UNEF、3/4-10UNC、3/4-16UNF、3/4-20UNEF、3/4-24UNS、7/8-14UNF、7/8-20UNEF、7/8-24UNS、15/16-28UN、1"-8UNC、1"-12UNF、1"-20UNEF、1-1/8-12UNF、1-1/8-16UN、1-1/4-7UNC、1-1/4-12UNF、1-1/2-6UNC等等。
美制螺纹对照表.xls
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 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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。
美制螺纹标准对照表
(0.875-9)
19.1770
19.7612
20.3911
20.5994
22.2250
1"-8
0.8650
0.8900
0.9188
0.9276
1.0000
22.10
22.40
(1.000-8)
21.9710
22.6060
23.3375
23.5610
25.4000
1.底孔直径指攻丝前钻孔直径，铸铁、黄铜等较软料取小值，钢、青铜等较硬料取大值。
9.20
9.40
(0.4375-14)
9.1440
9.5504
9.9339
10.0889
11.1125
1/2-13
0.4170
0.4340
0.4500
0.4565
0.5000
10.65
10.90
(0.50-13)
10.5918
11.0236
11.4300
11.5951
12.7000
9/16-12
0.4720
13.2207
13.3350
12.5197
5/8-18
0.6149
0.6236
0.5828
0.5875
0.5554
14.85
14.89
(0.625-18)
15.6185
15.8394
14.8031
14.9225
14.1072
3/4-16
0.7391
0.7485
0.7029
0.7079
0.6718
17.91
4.2113
4.2875
美制螺纹标准对照表(精品)
美制螺纹标准对照表美制外螺纹(２A)常用规格极限尺寸表(粗牙）公称尺寸和每英寸牙数螺纹系列代号大径极限中径极限小径maｘ螺胚直径最小最大最小最大最小最大8－32UNC ０.１571０.1６310.13990.14２80.１２48３.５８３.61(0.16４－32)3.９9０3４.1４27３.5５３53．62７13.16９910-240.1818０.18９00.15860.16１9０.１3794.07４.1０(0.190-24)4.6１774．80064.02844.1123３.５02７12-2４０．２0780.21500.1８４50.18790.1639４.724．7５(0.216－24)5.27８15．46104.６8６34.７727４．16３1１／4-20０.２４0．２4890.21270.21６４0.1876５．45５.4808(０.250 -20)6.11６3６.3２２1５.40265．４9６6４.76５05/１6-180.3０260.3113０．2７１20.27520.243１6.946.98(０．31 75-18)７.68607.90７６.８８856.99016．１7４73/8-1 60.36430．3７３70.32870.3３3１０．２９70８．408.44(0.375-16)9.25329.49２０8.34908.46０77.54３87／16-140.42580.４３61０.３8５0０.3897０.３48５9.839.87(０．437５-14)10．8１5311．076９９.779９.８9848.８5191/2－１30.４8760．4９８50.44350.44８50.404111．3411.３8(0．50-13)12.3850１2.661９11.26４９11．3９1９10.2641９/16－０．０.560０．５0．５００.451１１2５49５9０1６６8８7２．８02．84(０．5６25-1２)１3.957３１４．２46912.740612.8７2711．６5105／８-1１0．６1１3０.623４０.55890.56４40．５11914.27１4．3２(0．625 -11)15.527０1５.83４414.196114．3３581３.00233／4-100.73530.74820.6７7３0.６832０.6２5５17.28１７.33(0.７5０-10）18.676619.004317.2０3417.35３315.8８77７/８-9０．859２０.87310.79460.800９0.７36820．27２0.32(0.８７5-9)21．82372２.17６720．1８2８20．3429１8.714７１"-8０.９０.9９800．９１0０0.91680．84４623.222３．83027(1.０00-8）２4.968225.３49223.114０23．２86721.4５281.螺胚直径指滚丝前的尺寸,数值为依经验公式计算而得，在实践中需验证。
美制螺纹尺寸对照表
美制螺纹尺寸对照表螺纹是一种常用的连接方式，广泛应用于机械制造、汽车制造、航空航天等领域。
不同类型的螺纹具有不同的尺寸，而螺纹尺寸则是螺纹的重要参数之一。
为了方便使用和对照，制定了螺纹尺寸对照表，本文将针对美制螺纹尺寸对照表进行详细的介绍。
一、螺纹基本概念在了解美制螺纹尺寸对照表之前，我们首先需要了解一些螺纹的基本概念。
1. 螺纹类型：常见的螺纹类型有内螺纹和外螺纹两种。
内螺纹指的是螺纹内部的凹槽，外螺纹则是指螺纹外部的凸起。
2. 螺距：螺距是螺纹的一个重要参数，指的是同一螺纹上相邻两个螺纹峰值之间的距离。
3. 直径：直径是指螺纹的直径，分为内径和外径。
二、美制螺纹尺寸对照表是一种标准化的工具，用于指导螺纹的设计和制造。
下面是美制螺纹尺寸对照表的主要内容：1. 组成：美制螺纹尺寸对照表通常由两部分组成，一部分是内螺纹尺寸，另一部分是外螺纹尺寸。
2. 尺寸表示：美制螺纹尺寸通常使用英寸（inch）作为单位，按照一定的规则进行表示。
例如，1/4-20代表螺距为20英寸，直径为1/4英寸。
3. 分类：美制螺纹尺寸对照表按照螺距的不同进行分类，常见的分类有粗牙、细牙、超细牙等。
4. 标准：美制螺纹尺寸对照表通常按照一定的标准进行制定，以保证螺纹的互换性和通用性。
常用的标准有ANSI B1.1、ANSI B1.2等。
三、如何使用要正确使用美制螺纹尺寸对照表，需要掌握一定的技巧和方法。
下面是一些常用的使用方法：1. 确定螺纹类型：首先需要确定所需螺纹的类型，是内螺纹还是外螺纹。
2. 确定螺距：根据实际需求，确定所需螺距的范围。
3. 找到对应尺寸：在美制螺纹尺寸对照表中，根据螺距和直径范围，找到对应的螺纹尺寸。
4. 验证对照：通过实际测量或对照来验证所选用的螺纹尺寸是否准确。
四、注意事项在使用美制螺纹尺寸对照表时，需要注意以下几点：1. 细心查找：美制螺纹尺寸对照表中可能包含大量的数据，需要耐心细致地查找，确保选用正确的尺寸。
公制美制英制螺纹对照表
公制/美制/英制螺纹对照表A型美制螺纹（UNF）常用规格外螺纹螺纹-4 9/16"-19牙 14.28 13.08 -6 11/16''-16 17.46 16.1-8 13/16''-16 20.64 19.28-10 1''-14 25.40 23.57-12 1(3/16)''-12 30.00 28.32 -16 1(7/16)''-12 36.51 34.67 -20 1(11/16)''-12 42.86 41.02C型JIC37度美制UNF螺纹常用规格-4 7/16”-20 11.11 10.03-5 1/2”-20 12.70 11.32-6 9/16”-18 14.28 13.08-8 3/4”-16 19.00 17.68-10 7/8”-14 22.22 20.68-12 1(1/16)"-12 26.98 25.15 -16 1(5/16)"-12 33.33 31.5 -20 1(5/8)"-12 41.28 39.44 -24 1(7/8)"-12 47.62 45.8-32 2(1/2)"-12 63.5 61.67英制圆柱管螺纹（BSPP）常用规格-4 1/4”-19 13.157 11.55-6 3/8”-19 16.662 14.95-8 1/2”-14 20.955 18.63-12 3/4”-14 26.441 24.11-16 1”-11 33.249 30.29-20 1(1/4)''-11 41.91 38.95英制圆锥管螺纹（BSPT）常用规格基面大径基准距离1/4”-19 13.157 63/8”-19 16.662 6.41/2”-14 20.955 8.23/4”-14 26.441 9.51”-11 33.249 10.41(1/4)''-11 41.91 12.7美制圆锥管螺纹（NPT）1/8”-27 10.24 41/4”-18 13.60 43/8”-18 17.04 4.321/2”-14 21.22 4.483/4”-14 26.57 4.751”-11(1/2)” 33.22 4.61(1/4)”-11.5 41.96 4.832007-4-20 16:33评论(7)3/8-16 0.3643 0.3737 0.3287 0.3331 0.2970 8.40 8.44(0.375-16) 9.2532 9.4920 8.3490 8.4607 7.54387/16-14 0.4258 0.4361 0.3850 0.3897 0.3485 9.83 9.87(0.4375-14) 10.8153 11.0769 9.7790 9.8984 8.85191/2-13 0.4876 0.4985 0.4435 0.4485 0.4041 11.34 11.38(0.50-13) 12.3850 12.6619 11.2649 11.3919 10.26419/16-12 0.5495 0.5609 0.5016 0.5068 0.4587 12.80 12.84(0.5625-12) 13.9573 14.2469 12.7406 12.8727 11.65105/8-11 0.6113 0.6234 0.5589 0.5644 0.5119 14.27 14.32 (0.625-11) 15.5270 15.8344 14.1961 14.3358 13.00233/4-10 0.7353 0.7482 0.6773 0.6832 0.6255 17.28 17.33 (0.750-10) 18.6766 19.0043 17.2034 17.3533 15.88777/8-9 0.8592 0.8731 0.7946 0.8009 0.7368 20.27 20.32(0.875-9) 21.8237 22.1767 20.1828 20.3429 18.71471"-8 0.9830 0.9980 0.9100 0.9168 0.8446 23.22 23.27(1.000-8) 24.9682 25.3492 23.1140 23.2867 21.45281.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。
公制美制英制螺纹对照表
公制/美制/英制螺纹对照表A型美制螺纹（UNF）常用规格外螺纹螺纹-4 9/16"-19牙 14.28 13.08 -6 11/16''-16 17.46 16.1-8 13/16''-16 20.64 19.28-10 1''-14 25.40 23.57-12 1(3/16)''-12 30.00 28.32 -16 1(7/16)''-12 36.51 34.67 -20 1(11/16)''-12 42.86 41.02C型JIC37度美制UNF螺纹常用规格-4 7/16”-20 11.11 10.03-5 1/2”-20 12.70 11.32-6 9/16”-18 14.28 13.08-8 3/4”-16 19.00 17.68-10 7/8”-14 22.22 20.68-12 1(1/16)"-12 26.98 25.15 -16 1(5/16)"-12 33.33 31.5 -20 1(5/8)"-12 41.28 39.44 -24 1(7/8)"-12 47.62 45.8-32 2(1/2)"-12 63.5 61.67英制圆柱管螺纹（BSPP）常用规格-4 1/4”-19 13.157 11.55-6 3/8”-19 16.662 14.95-8 1/2”-14 20.955 18.63-12 3/4”-14 26.441 24.11-16 1”-11 33.249 30.29-20 1(1/4)''-11 41.91 38.95英制圆锥管螺纹（BSPT）常用规格基面大径基准距离1/4”-19 13.157 63/8”-19 16.662 6.41/2”-14 20.955 8.23/4”-14 26.441 9.51”-11 33.249 10.41(1/4)''-11 41.91 12.7美制圆锥管螺纹（NPT）1/8”-27 10.24 41/4”-18 13.60 43/8”-18 17.04 4.321/2”-14 21.22 4.483/4”-14 26.57 4.751”-11(1/2)” 33.22 4.61(1/4)”-11.5 41.96 4.832007-4-20 16:33评论(7)3/8-16 0.3643 0.3737 0.3287 0.3331 0.2970 8.40 8.44(0.375-16) 9.2532 9.4920 8.3490 8.4607 7.54387/16-14 0.4258 0.4361 0.3850 0.3897 0.3485 9.83 9.87(0.4375-14) 10.8153 11.0769 9.7790 9.8984 8.85191/2-13 0.4876 0.4985 0.4435 0.4485 0.4041 11.34 11.38(0.50-13) 12.3850 12.6619 11.2649 11.3919 10.26419/16-12 0.5495 0.5609 0.5016 0.5068 0.4587 12.80 12.84(0.5625-12) 13.9573 14.2469 12.7406 12.8727 11.65105/8-11 0.6113 0.6234 0.5589 0.5644 0.5119 14.27 14.32 (0.625-11) 15.5270 15.8344 14.1961 14.3358 13.00233/4-10 0.7353 0.7482 0.6773 0.6832 0.6255 17.28 17.33 (0.750-10) 18.6766 19.0043 17.2034 17.3533 15.88777/8-9 0.8592 0.8731 0.7946 0.8009 0.7368 20.27 20.32(0.875-9) 21.8237 22.1767 20.1828 20.3429 18.71471"-8 0.9830 0.9980 0.9100 0.9168 0.8446 23.22 23.27(1.000-8) 24.9682 25.3492 23.1140 23.2867 21.45281.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。
米制普通螺纹、统一螺纹(美制)、惠氏螺纹(英制)对照表
美制统一螺纹表UNC,UNF
公称 基本大经 牙数 系列 直径 D，d(in) n 代号 0 1 1 2 2 3 3 4 4 5 5 6 6 8 8 10 10 12 12 12 1/4 1/4 1/4 0.0600 0.0730 0.0730 0.0860 0.0860 0.0990 0.0990 0.1120 0.1120 0.1250 0.1250 0.1380 0.1380 0.1640 0.1640 0.1900 0.1900 0.2160 0.2160 0.2160 0.2500 0.2500 0.2500 80 64 72 56 64 48 56 40 48 40 44 32 40 32 36 24 32 24 28 32 20 28 32 18 UNF UNC UNF UNC UNF UNC UNF UNC UNF UNC UNF UNC UNF UNC UNF UNC UNF UNC UNF UNEF UNC UNF UNEF UNC 基本中经 D2，d2 0.0519 0.0629 0.0640 0.0744 0.0759 0.0855 0.0874 0.0958 0.0985 0.1088 0.1102 0.1177 0.1218 0.1437 0.1460 0.1629 0.1697 0.1889 0.1928 0.1957 0.2175 0.2268 0.2297 0.2764 UNR外螺纹设 内螺纹基本小 计牙型小径 径D1 d3(参考) 0.0465 0.0561 0.0580 0.0667 0.0691 0.0764 0.0797 0.0849 0.0894 0.0979 0.1004 0.1042 0.1109 0.1302 0.1339 0.1449 0.1562 0.1709 0.1773 0.1822 0.1959 0.2113 0.2162 0.2524 0.0447 0.0538 0.0560 0.0641 0.0668 0.0734 0.0771 0.0813 0.0864 0.0943 0.0971 0.0997 0.1073 0.1257 0.1299 0.1389 0.1517 0.1649 0.1722 0.1777 0.1887 0.2062 0.2117 0.2443 公制对照表(mm) 基本大经 D，d 1.5240 1.8542 1.8542 2.1844 2.1844 2.5146 2.5146 2.8448 2.8448 3.1750 3.1750 3.5052 3.5052 4.1656 4.1656 4.8260 4.8260 5.4864 5.4864 5.4864 6.3500 6.3500 6.3500 7.9375 (内)小径D1 1.1803 1.4246 1.4723 1.6934 1.7548 1.9418 2.0236 2.1574 2.2720 2.4876 2.5501 2.6459 2.8178 3.3063 3.4018 3.6803 3.9667 4.3407 4.5044 4.6271 4.9752 5.3680 5.4907 6.4099 (外)小径d3 1.1345 1.4246 1.4723 1.6934 1.7548 1.9418 2.0236 2.1574 2.2720 2.4876 2.5501 2.6459 2.8178 3.3063 3.4018 3.6803 3.9667 4.3407 4.5044 4.6271 4.9752 5.3680 5.4907 6.4099 螺距P 0.3175 0.3969 0.3528 0.4536 0.3969 0.5292 0.4536 0.6350 0.5292 0.6350 0.5773 0.7938 0.6350 0.7938 0.7056 1.0583 0.7938 1.0583 0.9071 0.7938 1.2700 0.9071 0.7938 1.4111 中经公差 容隙 2A 0.001762 0.001970 0.001899 0.002127 0.002040 0.002302 0.002191 0.002507 0.002361 0.002562 0.002484 0.002820 0.002614 0.002916 0.002804 0.003319 0.003004 0.003400 0.003224 0.003183 0.003731 0.003322 0.003228 0.004041 es 1A和2A 0.000529 0.000591 0.000570 0.000638 0.000612 0.000691 0.000657 0.000752 0.000708 0.000769 0.000745 0.000846 0.000784 0.000875 0.000841 0.000996 0.000901 0.001020 0.000967 0.000955 0.001119 0.000997 0.000968 0.001212
美制统一螺纹(UN)的标准系列及基本尺寸
美制统一螺纹(UN)
1864年,美国人威利.赛特斯（Willian Sellers）参照英国惠氏螺纹标准体系制定了美国国家螺纹（N）.这两种螺纹在直径与螺距系列和公差方面很相近，但美国国家螺纹的牙型（牙型角为60，削平高度为H/8）不同于惠氏螺纹牙型（牙型角为55，削平高度为H/6）在美国工业影响的地区和行业，美国家螺纹得到广泛应用.
第二次世界大战中，由于盟军所使用的螺纹标准不统一，后勤补给困难给盟军造成了严重的经济损失和人员伤亡.二战刚结束，美国英国和加拿大等盟国马上着手制定盟国间统一的螺纹标准，于1948年颁布了统一螺纹标准.由于当时美国的经济实力和军事实力在盟军内占主导地位，因此统一螺纹主要是依据美国国家螺纹标准而制定的，统一螺纹代号“UN”的前一个字母“U”来源于盟国间的“统一”；后一个字母“N”来源于美国国家螺纹的代号“N”.从此，统一螺纹开始挤占英国惠氏螺纹原有的使用市场.
表1-21统一螺纹的标准系列
统一粗牙螺纹（UNC或UNRC）的基本尺寸
统一细牙螺纹（UNC或UNRC）的基本尺寸。
美制一般密封管螺纹基本尺寸
圈数mm 圈数mm 1/16270.9410.7527.8947.142 6.389 4.324.0643 2.822 6.1371/8270.9410.75210.249.4898.737 4.364.1023 2.8228.4811/418 1.411 1.12913.6212.48711.358 4.15.7853 4.23310.9963/818 1.411 1.12917.0615.92614.797 4.326.0963 4.23314.4171/214 1.814 1.45121.2219.77218.321 4.488.1283 5.44317.8133/414 1.814 1.45126.5725.11723.666 4.758.6183 5.44323.127111.5 2.209 1.76733.2331.46129.694 4.610.163 6.62629.061 1/411.5 2.209 1.76741.9940.21838.451 4.8310.673 6.3537.7881 1/211.5 2.209 1.76748.0546.28744.52 4.8310.673 6.3543.853211.5 2.209 1.76760.0958.32556.558 5.0111.073 6.3555.8672 1/28 3.175 2.5472.770.15967.619 5.4617.342 6.3566.53538 3.175 2.5488.6186.06883.528 6.1319.462 6.3562.3113 1/28 3.175 2.54101.398.77696.236 6.5720.862 6.3594.93248 3.175 2.54114111.43108.893 6.7521.432 6.35107.55458 3.175 2.54141138.41135.8727.523.812 6.35134.38468 3.175 2.54167.8165.25162.7127.6624.322 6.35161.19188 3.175 2.54218.4215.9213.3618.526.992 6.35211.673108 3.175 2.54272.3269.77267.2329.6830.732 6.35265.311128 3.175 2.54323320.49317.95210.8834.542 6.35315.79314O.D.8 3.175 2.54354.9352.36349.82412.539.692 6.35347.34516O.D.8 3.175 2.54405.8403.24400.70414.546.042 6.35397.82818O.D 8 3.175 2.54456.6454.03451.4851650.82 6.35448.3120O.D.8 3.175 2.54507.2504.71502.1661753.982 6.35498.79224O.D.8 3.175 2.54608.6606.07603.5281960.332 6.35599.758小径d1=D1④标记：美制一般密封管螺纹的完整标记由螺纹特征代号，螺纹尺寸代号和旋向代号组成。
美制螺纹标准对照表
7.9070
6.8885
6.9901
6.1747
3/8-16
0.3643
0.3737
0.3287
0.3331
0.2970
8.40
8.44
(0.375-16)
9.2532
9.4920
8.3490
8.4607
7.5438
7/16-14
0.4258
0.4361
0.3850
0.3897
0.3485
5.8699
6.3500
5/16-24
0.2670
0.2770
0.2854
0.2902
0.3125
6.85
7.20
(0.3175-24)
6.7818
7.0358
7.2492
7.3711
7.9375
3/8-24
0.3300
0.3400
0.3479
0.3528
0.3750
8.45
8.78
(0.375-24)
0.1770
0.1860
0.1928
0.1970
0.2160
4.55
4.85
(0.216-28)
4.4958
4.7244
4.8971
5.0038
5.4864
1/4-28
0.2110
0.2200
0.2268
0.2311
0.2500
5.40
5.71
(0.250-28)
5.3594
5.5880
5.7607
0.5000
11.40
11.82
(0.50-20)