美制螺纹(统一螺纹)直径螺距组合表
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
公称直径基本大
径
D
牙
数
n
基本中
径
D2
UNR外螺纹设计
牙型小径（参考）
D2
内螺纹基本小径
D2
1/428 5/1624 3/824 7/1620 1/220
统一细牙螺纹（UNC或UNRC）的基本尺寸。
美制统一螺纹(UN)的标准系列及基本尺寸
美制统一螺纹(U N)的
标准系列及基本尺寸-CAL-FENGHAI.-(YICAI)-Company One1
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
公称直径基本大
径
D
牙数
n
基本中
径
D2
UNR外螺纹设计牙
型小径（参考）D2
内螺纹基本小径
D2
1/428 5/1624
统一细牙螺纹（UNC或UNRC）的基本尺寸。
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。
美制统一螺纹(UN)的标准系列及基本尺寸
美制统一螺纹(U N)的标准系
列及基本尺寸
-CAL-FENGHAI-(2020YEAR-YICAI)_JINGBIAN
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
公称直径基本大
径
D
牙数
n
基本中
径
D2
UNR外螺纹设计牙
型小径（参考）D2
内螺纹基本小径
D2
1/428 5/1624
统一细牙螺纹（UNC或UNRC）的基本尺寸。
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 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15.163815.455916.0883616.2229817.462515.4762211/16-16UN160.861.5882A 17.4269417.1881816.395716.2737815.534642B 15.74816.103616.4312616.5887417.462515.8753A17.462517.2237416.4312616.3398215.57023B 15.74815.9613616.4312616.548117.4625 1.587511/16-20UN200.7561.272A 17.4294817.2237416.6039816.4947615.918182B 16.078216.38316.63716.7792417.462516.271243A17.462517.2567616.63716.5557215.95123B 16.078216.2864816.63716.7436817.462516.2712411/16-24UNEF240.631.0582A 17.4320217.2491416.7436816.6420816.172182B 16.306816.560816.4947616.9062417.462516.271243A9.842517.2796216.7741616.6979616.30683B 16.306816.4947616.7741616.8732217.462516.2712411/16-28UN280.540.9072A 17.4345617.2694616.8452816.7487616.48462B 16.484616.687816.8732216.9976817.462516.667483A17.462517.297416.8732216.802116.48463B 16.484616.6395416.8732216.967217.462516.6674811/16-32UN320.4720.7942A 17.4345617.2821616.9189416.827516.489682B 16.611616.789416.9468817.0637217.462516.667483A17.462517.310116.9468816.878316.517623B 16.611616.7487616.9468817.0357817.462516.667483/4-10UNC101.5132.541A 19.0042818.5115217.3532817.1297615.979141B 16.306816.840217.39917.691119.0516.667482A 19.0042818.6766217.3532817.2034215.979142B 16.306816.840217.39917.5945819.0516.667483A19.0518.7223417.39917.2872416.024863B 16.306816.624317.39917.5437819.0516.667483/4-12UN121.262.1172A 19.0068218.7172617.6326817.4929816.487142B 16.76417.221217.6758617.8587419.0517.066263A19.0518.7604417.6758617.5717216.530323B 16.76417.0357817.6758617.8130219.0517.066263/4-14UNS 14 1.081 1.8142A 19.011918.7502817.8333417.703816.59892B 17.094217.475217.8714418.0416219.0517.066263/4-16UNF160.861.5881A 19.011918.6512217.9806617.7901617.11961B 17.322817.678418.0187618.2676819.0517.46252A19.011918.7731417.9806617.8536617.11962B 17.322817.678418.0187618.1838619.0517.46253A19.0518.8112418.0187617.9222417.15773B 17.322817.5463218.0187618.1432219.0517.46253/4-18UNS 180.841 1.4112A 19.0144418.7934618.326117.9806617.33552B 17.52617.856218.1330618.2854619.0517.46253/4-20UNEF200.7561.272A 19.0169818.8112418.1914818.0797217.505682B 17.678417.957818.224518.3692819.0517.858743A19.0518.8442618.224518.1406817.53873B 17.678417.8739818.224518.3337219.0517.858743/4-24UNEF240.631.0582A19.0195218.8366418.3311818.2270417.759682B17.90718.16118.3616618.4962819.0517.858740.6875"17.4630.75"19.05螺纹小径螺纹外径MaxMinMaxMinMaxMin 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3A19.0195218.8493418.4073818.3083217.899383B 18.03418.262618.4378618.567419.0517.858743/4-28UN280.540.9072A 19.0195218.8544218.4302418.3337217.937482B 18.059418.28818.4607218.5877219.0518.254983A19.0518.884918.4607218.3870617.967963B 18.059418.2270418.4607218.554719.0518.254983/4-32UN320.4720.7842A 19.0220618.8696618.5064418.41518.077182B 18.186418.389618.5343818.6537619.0518.254983A19.0518.897618.5343818.465818.105123B 18.186418.3362618.5343818.6258219.0518.2549813/16-10UNC101.5132.542A 20.5917820.2641218.986518.8366417.612362B 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 19.786619.964420.1218820.2412620.637519.842483A20.637520.485120.1218820.053319.692623B 19.786619.9237620.1218820.2133220.637519.842487/8-9UNC91.682.8221A 22.1767421.6484220.3428620.1015618.816321B 19.17719.761220.8483220.7035422.22519.446242A 22.1767421.8236820.3428620.1828418.816322B 19.17719.761220.8483220.599422.22519.446243A22.22521.8719420.3911220.2717418.864583B 19.17719.5097420.8483220.5460622.22519.446247/8-10UNS 10 1.513 2.542A 22.1792821.8516220.5282820.3758819.156682B 19.481820.015220.57420.7721222.22519.842487/8-12UN121.262.1172A 22.1818221.8922620.8076820.6679819.662142B 19.93920.396220.8508621.0337422.22520.241263A22.22521.9354420.8508620.7467219.705323B 19.93920.1879220.8508620.9880222.22520.241267/8-14UNF141.0811.8141A22.1843621.7906621.005820.8000620.025361B20.269220.675621.0464421.3156822.22520.63750.8125"20.638螺纹小径螺纹外径MaxMinMax MinMaxMin Max MinMaxMin 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2A 22.1843621.9227421.005820.8686420.025362B 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。
美制英制公制螺纹孔尺寸表
螺纹规格-美制、英制、公制美制细牙UNF 2A 外螺纹大径UNFUN 2B内螺纹小径（UN、UNF）序号规格型号最大最小公差最小最大公差1 7/16"-20 11.079 10.874 0.206 9.728 10.033 0.3052 1/2"-20 12.667 12.461 0.206 11.328 11.608 0.2793 9/16"-18 14.252 14.031 0.221 12.751 13.081 0.3304 3/4"-16 19.012 18.773 0.239 17.323 17.678 0.3565 7/8"-14 22.184 21.923 0.262 20.269 20.676 0.406-12 26.944 26.655 0.290 24.689 25.146 0.457 6 11/16-12 33.294 33.005 0.290 31.039 31.496 0.457 7 15/168 15/-12 41.229 40.940 0.290 38.989 39.446 0.4578-12 47.579 47.290 0.290 45.339 45.796 0.457 9 17/8-12 63.452 63.162 0.290 61.214 61.671 0.457 10 21/2公制细牙6g外螺纹大径6H内螺纹小径1 M10*1 9.974 9.794 0.180 8.917 9.157 0.2402 M12*1.5 11.968 11.732 0.236 10.376 10.676 0.3003 M14*1.5 13.968 13.732 0.236 12.376 12.676 0.3004 M16*1.5 15.968 15.732 0.236 14.376 14.676 0.3005 M18*1.5 17.968 17.732 0.236 16.376 16.676 0.3006 M20*1.5 19.968 19.732 0.236 18.376 18.676 0.3007 M22*1.5 21.968 21.732 0.236 20.376 20.676 0.3008 M24*1.5 23.968 23.732 0.236 22.376 22.676 0.3009 M26*1.5 25.968 25.732 0.236 24.376 24.676 0.30010 M27*1.5 26.968 26.732 0.236 25.376 25.676 0.30011 M30*1.5 29.968 29.732 0.236 28.376 28.676 0.3000.375 12 M27*2 26.962 26.682 0.280 24.83525.21013 M30*2 29.962 29.682 0.280 27.835 28.210 0.37514 M33*2 32.962 32.682 0.280 30.835 31.210 0.37515 M36*2 35.962 35.682 0.280 33.835 34.210 0.37516 M42*2 41.962 41.682 0.280 39.835 40.210 0.375英制管螺纹1 G1/8-28 9.728 9.514 0.214 8.566 8.848 0.2822 G1/4-19 13.157 12.907 0.250 11.445 11.890 0.4453 G3/8-19 16.662 16.412 0.250 14.950 15.395 0.4454 G1/2-14 20.955 20.671 0.284 18.631 19.172 0.5415 G3/4-14 26.441 26.157 0.284 24.117 24.658 0.5416 G1-11 33.249 32.889 0.360 30.291 30.931 0.640-11 41.910 41.550 0.360 38.952 39.592 0.6407 G11/4-11 47.803 47.443 0.360 44.845 45.485 0.6408 G11/2公制/美制/英制螺纹对照表给大家分享一下 A型美制螺纹（UNF）常用规格牙型角60外螺纹内螺纹 -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 2 5.40 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 41.02 C型JIC37度美制UNF螺纹常用规格牙型角60-4 7/16”-20 11.11 10.03 -5 1/2”-20 12.70 11.32-6 9/16”-18 14.28 13.08 -83/4”-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）常用规格牙型角55-4 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）常用规格牙型角55基面大径基准距离1/4”-19 13.157 6 3/8”-19 16.662 6.4 1/2”-14 20.955 8.2 3/4”-14 26.441 9.5 1”-11 33.249 10.4 1(1/4)''-11 41.91 12.7 美制圆锥管螺纹（NPT）牙型角601/8”-27 10.24 4 1/4”-18 13.60 4 3/8”-18 17.04 4.32 1/2”-14 21.22 4.48 3/4”-14 26.57 4.75 1”-11(1/2)” 33.22 4.6 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。
美制统一螺纹表UNC-UNF
内螺纹基本小 径D1
UNR外螺纹设 计牙型小径
d3(参考)
0.2584
0.2512
0.2674
0.2614
0.2738
0.2687
0.2787
0.2742
0.3073
0.2983
0.3209
0.3137
0.3299
0.3239
0.3363
0.3312
0.3412
0.3367
0.3602
0.3499
0.3698
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
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
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
美制统一螺纹表
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
公称直径基本大
径
D
牙数
n
基本中
径
D2
UNR外螺纹设计牙
型小径（参考）D2
内螺纹基本小径
D2
1/428 5/1624
统一细牙螺纹（UNC或UNRC）的基本尺寸。
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
公称直径基本大
径
D
牙数
n
基本中
径
D2
UNR外螺纹设计牙型
小径（参考）D2
内螺纹基本小径
D2
1/4 0.2500 28 0.2268 0.2074 0.2113 5/16 0.3125 24 0.2854 0.2629 0.2674
统一细牙螺纹（UNC或UNRC）的基本尺寸。
美制统一螺纹表
内螺纹小经极限尺寸 小径 D1(min) 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 6.5627 6.7918 6.9555 7.0782 7.8065 8.1502 8.3793 8.5430 8.6657 9.1485 9.3940 9.7377 10.1305 10.2532 10.5849 10.9815 11.3252 11.7180 11.8407 11.9961 12.5690 8 页 1B和2B (max) 1.3566 1.6162 1.6399 1.8876 1.9218 2.1475 2.1970 2.3853 2.4591 2.6978 2.7397 2.8937 3.0136 3.5267 3.5966 3.9493 4.1673 4.5895 4.7173 4.8126 5.2673 5.5818 5.6793 6.7313 6.8548 7.0388 7.1693 7.2668 8.1637 8.4423 8.6263 8.7568 8.8543 9.5502 9.7512 10.0298 10.3443 10.4418 11.0132 11.3387 11.6173 11.9318 12.0293 12.4548 12.9262 3B (max) 1.3566 1.6162 1.6399 1.8876 1.9218 2.1475 2.1970 2.3853 2.4591 2.6978 2.7397 2.8937 3.0136 3.5267 3.5966 3.9493 4.1673 4.5895 4.7173 4.8126 5.2492 5.5638 5.6612 6.6795 6.8062 6.9953 7.1295 7.2296 8.0827 8.3734 8.5658 8.7025 8.8044 9.4407 9.6521 9.9463 10.2796 10.3829 10.8810 11.2259 11.5230 11.8593 11.9636 12.3005 12.8029
美制螺纹尺寸表(mm)
美制螺纹尺寸表(mm)美制螺纹尺寸表（mm）1. 引言螺纹是机械连接中常见的连接形式，具有良好的承力性能和可重复使用性。
在制造过程中，精确的螺纹尺寸是非常重要的，以确保螺纹零件的互换性和相互配合性。
本文将介绍美制螺纹尺寸表（mm）中常见的螺纹类型及其规格。
2. UNC螺纹尺寸表(mm)UNC（Unified Coarse Thread）螺纹是一种粗牙螺纹，常用于一般机械制造和装配。
以下是UNC螺纹常见尺寸表(mm)的部分内容：- 1/4-20：意味着螺纹直径为1/4英寸，每英寸有20条螺纹- 5/16-18：意味着螺纹直径为5/16英寸，每英寸有18条螺纹- 3/8-16：意味着螺纹直径为3/8英寸，每英寸有16条螺纹UNC螺纹尺寸表中还包括更多的螺纹规格，根据具体的需求可以进行选择。
3. UNF螺纹尺寸表(mm)UNF（Unified Fine Thread）螺纹是一种细牙螺纹，常用于对连接强度和紧固力有较高要求的场合。
以下是UNF螺纹常见尺寸表(mm)的部分内容：- 1/4-28：意味着螺纹直径为1/4英寸，每英寸有28条螺纹- 5/16-24：意味着螺纹直径为5/16英寸，每英寸有24条螺纹- 3/8-24：意味着螺纹直径为3/8英寸，每英寸有24条螺纹UNF螺纹尺寸表中也有其他规格的螺纹，可根据具体需求选用。
4. UNEF螺纹尺寸表(mm)UNEF（Unified Extra Fine Thread）螺纹是一种超细牙螺纹，常用于对紧固性能要求极高的场合。
以下是UNEF螺纹常见尺寸表(mm)的部分内容：- 1/4-32：意味着螺纹直径为1/4英寸，每英寸有32条螺纹- 5/16-36：意味着螺纹直径为5/16英寸，每英寸有36条螺纹- 3/8-40：意味着螺纹直径为3/8英寸，每英寸有40条螺纹UNE F螺纹尺寸表可供选择的规格较少，但在某些特殊应用场合中仍然发挥着重要作用。
5. 总结美制螺纹尺寸表（mm）是机械制造中常用的螺纹连接标准。