英制螺纹尺寸公差表
单位：毫米
规格代号
系列 代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
1
0.060—80 （0#—80）
3/50-80
UNF
2
0.3175
1.5113 –0.08128
1.30556 –0.04572
1.12268
1.1811 +0.12446
1.3182 +0.05842
1.524
3
0.3175
1.5240 –0.08128
1.3182 –0.03302
1.13538
1.1811 +0.12446
1.3182 +0.04318
1.524
2
0.073—64 （1#—64）
UNC
2
0.396875
1.83896 –0.09652
1.58242 –0.0508
1.35128
1.42494 +0.15748
1.59766 +0.06604
1.8542
3
0.396875
1.8542 –0.09652
1.59766 –0.0381
1.36652
1.42494 +0.15748
1.59766 +0.04826
1.8542
3
0.073—72 （1#—72）
73/1000-72
UNF
2
0.352777
1.83896 –0.0889
1.61036 –0.04826
1.40716
1.4732 +0.1397
1.6256 +0.0635
1.8542
3
0.352777
1.8542 –0.0889
1.6256 –0.03556
1.4224
1.4732 +0.1397
1.6256 +0.04826
1.8542
4
0.086—56 （2#—56）
UNC
2
0.453571
2.16916 –0.10414
1.87452 –0.05334
1.6129
1.69418 +0.1778
1.88976 +0.07112
2.1844
3
0.453571
2.1844 –0.10414
1.88976 –0.04064
1.62814
1.69418 +0.1778
1.88976 +0.05334
2.1844
5
0.086—64 （2#—64）
43/500-64
UNF
2
0.396875
2.16916 –0.09652
1.91262 –0.0508
1.68148
1.75514 +0.15748
1.92786 +0.06858
2.1844
3
0.396875
2.1844 –0.09652
1.92786 –0.0381
1.69672
1.75514 +0.15748
1.92786 +0.0508
2.1844
6
0.099—48 （3#—48）
UNC
2
0.529166
2.49682 –0.1143
2.15392 –0.05842
1.84658
1.94056 +0.20574
2.1717 +0.07620
2.5146
3
0.529166
2.5146 –0.1143
2.1717 –0.04318
1.86436
1.94056 +0.20574
2.1717 +0.05588
2.5146
7
0.099—56 （3#—56）
99/1000-56
UNF
2
0.453571
2.49682 –0.10414
2.20218 –0.05588
1.94056
2.02438 +0.17272
2.21996 +0.07112
2.5146
3
0.453571
2.5146 –0.10414
2.21996 –0.04064
1.95834
2.02438 +0.17272
2.21996 +0.05334
2.5146
8
0.112—40 （4#—40）
UNC
2
0.635
2.82448 –0.12954
2.413 –0.0635
2.0447
2.15646 +0.2286
2.43332 +0.08382
2.8448
3
0.635
2.8448 –0.12954
2.43332 –0.04826
2.06502
2.15646 +0.2286
2.43332 +0.06096
2.8448
9
0.112—48 （4#—48）
14/125-48
UNF
2
0.529166
2.82702 –0.1143
2.48412 –0.06096
2.17678
2.27076 +0.18796
2.5019 +0.07874
2.8448
3
0.529166
2.8448 –0.1143
2.5019 –0.04572
2.19456
2.27076 +0.18796
2.5019 +0.05842
2.8448
10
0.125—40 （5#—40）
UNC
2
0.635
3.15468 –0.12954
2.7432 –0.06604
2.3749
2.48666 +0.21082
2.76352 +0.08382
3.175
3
0.635
3.175 –0.12954
2.76352 –0.04826
2.39522
2.48666 +0.21082
2.76352 +0.0635
3.175
11
0.125—44 （5#—44）
1/8
UNF
2
0.577273
3.15722 –0.12192
2.7813 –0.0635
2.44856
2.55016 +0.1905
2.79908 +0.08128
3.175
3
0.577273
3.175 –0.12192
2.79908 –0.04826
2.46634
2.55016 +0.1905
2.79908 +0.06096
3.175
12
0.138—32 （6#—32）
UNC
2
0.79375
3.48488 –0.1524
2.96926 –0.07112
2.51206
2.6416 +0.254
2.98958 +0.09398
3.5052
3
0.79375
3.5052 –0.1524
2.98958 –0.05334
2.53238
2.6416 +0.254
2.98958 +0.06858
3.5052
13
0.138—40 （6#—40）
69/500
UNF
2
0.635
3.48488 –0.12954
3.0734 –0.06604
2.7051
2.8194 +0.2032
3.09372 +0.08636
3.5052
3
0.635
3.5052 –0.12954
3.09372 –0.0508
2.72542
2.8194 +0.19304
3.09372 +0.0635
3.5052
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
14
0.164—32 （8#—32）
UNC
2
0.79375
4.14274 –0.1524
3.62712 –0.07366
3.16992
3.302 +0.2286
3.64998 +0.09652
4.1656
3
0.79375
4.1656 –0.1524
3.64998 –0.05588
3.19278
3.302 +0.22606
3.64998 +0.07112
4.1656
15
0.164—36 （8#—36）
41/250-36
UNF
2
0.70555
4.14528 –0.1397
3.68808 –0.07112
3.27914
3.4036 +0.2032
3.7084 +0.09144
4.1656
3
0.70555
4.1656 –0.1397
3.7084 –0.05334
3.29946
3.4036 +0.19304
3.7084 +0.06858
4.1656
16
0.190—24 （10#—24）
UNC
2
1.05833
4.8006 –0.18288
4.11226 –0.08382
3.50266
3.683 +0.2794
4.13766 +0.10922
4.826
3
1.05833
4.826 –0.18288
4.13766 –0.0635
3.52806
3.683 +0.2667
4.13766 +0.08128
4.826
17
0.190—32（10#—32）
19/100-32
UNF
2
0.79375
4.80314 –0.1524
4.28752 –0.0762
3.83032
3.9624 +0.2032
4.31038 +0.09906
4.826
3
0.79375
4.826 –0.1524
4.31038 –0.05842
3.85318
3.9624 +0.20574
4.31038 +0.07366
4.826
18
0.216—24
UNC
2
1.05833
5.461 –0.18288
4.77266 –0.08636
4.16306
4.3434 +0.254
4.79806 +0.11176
5.4864
3
1.05833
5.4864 –0.18288
4.79806 –0.06604
4.18846
4.3434 +0.24638
4.79806 +0.8382
5.4864
19
0.216—28
UNF
2
0.90714
5.461 –0.1651
4.87172 –0.08128
4.34848
4.4958 +0.2286
4.89712 +0.10668
5.4864
3
0.90714
5.4864 –0.1651
4.89712 –0.06096
4.37388
4.4958 +0.22098
4.89712 +0.07874
5.4864
20
0.216—32 27/125-32
UNEF
2
0.79375
5.46354 –0.1524
4.94792 –0.07874
4.49072
4.6228 +0.2032
4.97078 +0.10414
5.4864
3
0.79375
5.4864 –0.1524
4.97078 –0.06096
4.51358
4.6228 +0.1905
4.97078 +0.07874
5.4864
21
0.250—20 1/4—20
UNC
1
1.27
6.32206 –0.30988
5.49656 –0.14224
4.76504
4.9784 +0.2794
5.5245 +0.18542
6.35
2
1.27
6.32206 –0.20574
5.49656 –0.09398
4.76504
4.9784 +0.2794
5.5245 +0.12446
6.35
3
1.27
6.35 –0.20574
5.5245 –0.07112
4.79298
4.9784 +0.27178
5.5245 +0.09144
6.35
22
0.250—28 1/4—28
UNF
1
0.90714
6.3246 –0.24892
5.73532 –0.127
5.21208
5.3594 +0.2286
5.76072 +0.1651
6.35
2
0.90714
6.3246 –0.1651
5.73532 –0.08382
5.21208
5.3594 +0.2286
5.76072 +0.10922
6.35
3
0.90714
6.35 –0.1651
5.76072 –0.0635
5.23748
5.3594 +0.2032
5.76072 +0.08128
6.35
23
0.250—32 1/4—32
UNEF
2
0.79375
6.3246 –0.1524
5.80898 –0.8128
5.35178
5.4864 +0.2032
5.83438 +0.10668
6.35
3
0.79375
6.35 –0.1524
5.83438 –0.6096
5.37718
5.4864 +0.17526
5.83438 +0.07874
6.35
24
.3125－18 5/16－18
UNC
1
1.41111
7.90702 –0.33274
6.99008 –0.15494
6.17474
6.4008 +0.3302
7.02056 +0.20066
7.9375
2
1.41111
7.90702 –0.22098
6.99008 –0.1016
6.17474
6.4008 +0.3302
7.02056 +0.13462
7.9375
3
1.41111
7.9375 –0.22098
7.02056 –0.0762
6.20522
6.4008 +0.2794
7.02056 +0.09906
7.9375
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
25
.3125—20 5/16—20
UN
2
1.27
7.90702 –0.20574
7.08152 –0.1016
6.35
6.5532 +0.3048
7.112 +0.13208
7.9375
3
1.27
7.9375 –0.20574
7.112 –0.0762
6.38048
6.5532 +0.254
7.112 +0.09906
7.9375
26
.3125—24 5/16—24
UNF
1
1.058333
7.90956 –0.27432
7.22122 –0.1397
6.61162
6.7818 +0.254
7.24916 +0.18034
7.9375
2
1.058333
7.90956 –0.18288
7.22122 –0.09398
6.61162
6.7818 +0.254
7.24916 +0.12192
7.9375
3
1.058333
7.9375 –0.18288
7.24916 –0.6858
6.63956
6.7818 +0.21336
7.24916 +0.09144
7.9375
27
.3125—28 5/16—28
UN
2
0.90714
7.9121 –0.1651
7.32282 –0.8636
6.79958
6.9596 +0.2032
7.34822 +0.11176
7.9375
3
0.90714
7.9375 –0.1651
7.34822 –0.06604
6.82498
6.9596 +0.17018
7.34822 +0.08382
7.9375
28
.3125—32 5/16—32
UNEF
2
0.79375
7.9121 –0.1524
7.39648 –0.08128
6.93928
7.0866 +0.1778
7.42188 +0.10668
7.9375
3
0.79375
7.9375 –0.1524
7.42188 –0.06096
6.96468
7.0866 +0.14478
7.42188 +0.7874
7.9375
29
0.375—16 3/8—16
UNC
1
1.5875
9.49198 –0.36068
8.46074 –0.1651
7.5438
7.7978 +0.3556
8.49376 +0.2159
9.525
2
1.5875
9.49198 –0.23876
8.46074 –0.11176
7.5438
7.7978 +0.3556
8.49376 +0.14478
9.525
3
1.5875
9.525 –0.23876
8.49376 –0.08382
7.57682
7.7978 +0.28448
8.49376 +0.10922
9.525
30
0.375—20 3/8—20
UN
2
1.27
9.49452 –0.20574
8.66902 –0.10414
7.9375
8.1534 +0.2794
8.6995 +0.13716
9.525
3
1.27
9.525 –0.20574
8.6995 –0.07874
7.96798
8.1534 +0.22098
8.6995 +0.1016
9.525
31
0.375—24 3/8—24
UNF
1
1.058333
9.49706 –0.27432
8.80872 –0.14478
8.19912
8.382 +0.254
8.83666 +0.18796
9.525
2
1.058333
9.49706 –0.18288
8.80872 –0.09652
8.19912
8.382 +0.254
8.83666 +0.12466
9.525
3
1.058333
9.525 –0.18288
8.83666 –0.07366
8.22706
8.382 +0.18288
8.83666 +0.09398
9.525
32
0.375—28 3/8—28
UN
2
0.90714
9.49706 –0.1651
8.90778 –0.09144
8.38454
8.5344 +0.2286
8.93572 +0.11684
9.525
3
0.90714
9.525 –0.1651
8.93572 –0.06858
8.41248
8.5344 +0.16764
8.93572 +0.0889
9.525
33
0.375—32 3/8—32
UNEF
2
0.79375
9.4996 –0.1524
8.98398 –0.08636
8.52678
8.6614 +0.2032
9.00938 +0.11176
9.525
3
0.79375
9.525 –0.1524
9.00938 –0.0635
8.55218
8.6614 +0.14986
9.00938 +0.08382
9.525
34
7/16—14
UNC
1
1.814286
11.07694 –0.3937
9.89838 –0.18034
8.8519
9.144 +0.4064
9.93394 +0.23368
11.1125
2
1.814286
11.07694 –0.26162
9.89838 –0.11938
8.8519
9.144 +0.4064
9.93394 +0.15494
11.1125
3
1.814286
11.1125 –0.26162
9.93394 –0.0889
8.88746
9.144 +0.29718
9.93394 +0.11684
11.1125
35
7/16—16
UN
2
1.5875
11.07694 –0.23876
10.0457 –0.11684
9.12876
9.398 +0.3556
10.08126 +0.14986
11.1125
3
1.5875
11.1125 –0.23876
10.08126 –0.08636
9.16432
9.398 +0.254
10.08126 +0.1143
11.1125
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
36
7/16—20
UNF
1
1.27
11.07948 –0.30988
10.25398 –0.16002
9.52246
9.7282 +0.3048
10.287 +0.20574
11.1125
2
1.27
11.07948 –0.20574
10.25398 –0.10668
9.52246
9.7282 +0.3048
10.287 +0.13716
11.1125
3
1.27
11.1125 –0.20574
10.287 –0.07874
9.55548
9.7282 +0.21844
10.287 +0.10414
11.1125
37
7/16—28
UNEF
2
0.907143
11.08456 –0.1651
10.49528 –0.09144
9.97204
10.1346 +0.2032
10.52322 +0.11684
11.1125
3
0.907143
11.1125 –0.1651
10.52322 –0.06858
9.99998
10.1346 +0.1549
10.52322 +0.0889
11.1125
38
7/16—32
UN
2
0.79375
11.0871 –0.1524
10.57148 –0.08636
10.11248
10.2616 +0.1778
10.59688 +0.11176
11.1125
3
0.79375
11.1125 –0.1524
10.59688 –0.0635
10.13968
10.2616 +0.1372
10.59688 +0.08382
11.1125
39
1/2—13
UNC
1
1.953846
12.6619 –0.41402
11.3919 –0.18796
10.26414
10.5918 +0.4318
11.43 +0.24638
12.7
2
1.953846
12.6619 –0.27686
11.3919 –0.127
10.26414
10.5918 +0.4318
11.43 +0.1651
12.7
3
1.953846
12.700 –0.27686
11.43 –0.09398
10.30224
10.5918 +0.2896
11.43 +0.12192
12.7
40
01/2—16
UN
2
1.5875
12.66444 –0.23876
11.6332 –0.11938
10.71626
10.9728 +0.3556
11.66876 +0.15494
12.7
3
1.5875
12.700 –0.23876
11.66876 –0.0889
10.75182
10.9728 +0.2515
11.66876 +0.11684
12.7
41
1/2—20
UNF
1
1.27
12.66698 –0.30988
11.84148 –0.16256
11.10996
11.3284 +0.4318
11.8745 +0.21336
12.7
2
1.27
12.66698 –0.20574
11.84148 –0.10922
11.10996
11.3284 +0.4318
11.8745 +0.14224
12.7
3
1.27
12.700 –0.20574
11.8745 –0.08128
11.14298
11.3284 +0.1956
11.8745 +0.10668
12.7
42
1/2—28
UNEF
2
0.907143
12.67206 –0.1651
12.08278 –0.09398
11.55954
11.7094 +0.2286
12.11072 +0.12192
12.7
3
0.907143
12.700 –0.1651
12.11072 –0.07112
11.58748
11.7094 +0.1676
12.11072 +0.09144
12.7
43
1/2—32
UN
2
0.79375
12.6746 –0.1524
12.15898 –0.0889
11.70178
11.8364 +0.2032
12.18438 +0.1143
12.7
3
0.79375
12.700 –0.1524
12.18438 –0.06604
11.72718
11.8364 +0.1498
12.18438 +0.08636
12.7
44
9/16—12
UNC
1
2.116667
14.24686 –0.43688
12.87272 –0.19812
11.65098
11.9888 +0.4572
12.91336 +0.25908
14.2875
2
2.116667
14.24686 –0.28956
12.87272 –0.13208
11.65098
11.9888 +0.4572
12.91336 +0.17272
14.2875
3
2.116667
14.2875 –0.28956
12.91336 –0.09906
11.70178
11.9888 +0.3124
12.91336 +0.12954
14.2875
45
9/16—16
UN
2
1.5875
14.25194 –0.23876
13.2207 –0.11938
12.30376
12.573 +0.3556
13.25626 +0.15494
14.2875
3
1.5875
14.2875 –0.23876
13.25626 –0.0889
12.33932
12.573 +0.2286
13.25626 +0.11684
14.2875
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
46
9/16—18
UNF
1
1.41111
14.25194 –0.33274
13.335 –0.17272
12.51966
12.7508 +0.3302
13.37056 +0.22606
14.2875
2
1.41111
14.25194 –0.22098
13.335 –0.1143
12.51966
12.7508 +0.3302
13.37056 +0.14986
14.2875
3
1.41111
14.2875 –0.22098
13.37056 –0.8636
12.55522
12.7508 +0.2184
13.37056 +0.11176
14.2875
47
9/16—20
UN
2
1.27
14.25448 –0.20574
13.42898 –0.10668
12.69746
12.9032 +0.3048
13.462 +0.1397
14.2875
3
1.27
14.2875 –0.20574
13.462 –0.08128
12.73048
12.9032 +0.2083
13.462 +0.10414
14.2875
48
9/16—24
UNEF
2
1.05833
14.25702 –0.18288
13.56868 –0.09906
12.95908
13.1318 +0.254
13.59916 +0.12954
14.2875
3
1.05833
1402875 –0.18288
13.59916 –0.07366
12.98956
13.1318 +0.1879
13.59916 +0.09652
14.2875
49
9/16—28
UN
2
0.90714
14.25956 –0.1651
13.67028 –0.09398
13.14704
13.3096 +0.2032
13.69822 +0.11684
14.2875
3
0.90714
14.2875 –0.1651
13.69822 –0.07112
13.17498
13.3096 +0.1549
13.69822 +0.09144
14.2875
50
9/16—32
UN
2
0.79375
14.2621 –0.1524
13.74648 –0.0889
13.28928
13.4366 +0.1778
13.77188 +0.1143
14.2875
3
0.79375
14.2875 –0.1524
13.77188 –0.06604
13.31468
13.4366 +0.1372
13.77188 +0.08636
14.2875
51
5/8—11
UNC
1
2.30909
15.83436 –0.46228
14.33576 –0.21082
13.00226
13.3858 +0.4826
14.3764 +0.27178
15.875
2
2.30909
15.83436 –0.30734
14.33576 –0.1397
13.00226
13.3858 +0.4826
14.3764 +0.18288
15.875
3
2.30909
15.875 –0.30734
14.3764 –0.10414
13.0429
13.3858 +0.3073
14.3764 +0.13716
15.875
52
5/8—12
UN
2
2.116667
15.83436 –0.28956
14.46022 –0.13716
12.98448
13.589 +0.4572
14.50086 +0.18034
15.875
3
2.116667
15.875 –0.28956
14.50086 –0.10414
13.27912
13.589 +0.28702
14.50086 +0.13462
15.875
53
5/8—16
UN
2
1.5875
15.83944 –0.23876
14.8082 –0.12192
13.89126
14.1478 +0.3556
14.84376 +0.15748
15.875
3
1.5875
15.875 –0.23876
14.84376 –0.09144
13.92682
14.1478 +0.2337
14.84376 +0.11684
15.875
54
5/8—18
UNF
1
1.411111
15.83944 –0.33274
14.9225 –0.1778
14.10716
14.351 +0.3302
14.95806 +0.23114
15.875
2
1.411111
15.83944 –0.22098
14.9225 –0.11938
14.10716
14.351 +0.3302
14.95806 +0.1524
15.875
3
1.411111
15.875 –0.22098
14.95806 –0.0889
14.14272
14.351 +0.2032
14.95806 +0.1143
15.875
55
5/8—20
UN
2
1.27
15.84198 –0.20574
15.01648 –0.10922
14.28496
14.5034 +0.2794
15.0495 +0.14224
15.875
3
1.27
15.875 –0.20574
15.0495 –0.08128
14.31798
14.5034 +0.1956
15.0495 +0.10668
15.875
56
5/8—24
UNEF
2
1.05833
15.84452 –0.18288
15.15618 –0.1016
14.54658
14.732 +0.254
15.18666 +0.13208
15.875
3
1.05833
15.875 –0.18288
15.18666 –0.0762
14.57706
14.732 +0.17526
15.18666 +0.09906
15.875
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
57
5/8—28
UN
2
0.907143
15.84706 –0.1651
15.25778 –0.09652
14.73454
14.8844 +0.2286
15.28572 +0.12446
15.875
3
0.907143
15.875 –0.1651
15.28572 –0.07112
14.76248
14.8844 +0.1676
15.28572 +0.09398
15.875
58
5/8—32
UN
2
0.79375
15.84706 –0.1524
15.33144 –0.09144
14.87424
15.0114 +0.2032
15.35938 +0.11684
15.875
3
0.79375
15.875 –0.1524
15.35938 –0.06858
14.90218
15.0114 +0.1499
15.35938 +0.0889
15.875
59
11/16—12
UN
2
2.11667
17.42186 –0.28956
16.04772 –0.13716
14.82598
15.1638 +0.4572
16.08836 +0.18034
17.4625
3
2.11667
17.4625 –0.28956
16.08836 –0.10414
14.86662
15.1638 +0.2921
16.08836 +0.13462
17.4625
60
11/16—16
UN
2
1.5875
17.42694 –0.23876
16.3957 –0.12192
15.47876
15.748 +0.3556
16.43126 +0.15748
17.4625
3
1.5875
17.4625 –0.23876
16.43126 –0.09144
15.51432
15.748 +0.21336
16.43126 +0.11684
17.4625
61
11/16—20
UN
2
1.27
17.42948 –0.20574
16.60398 –0.1092
15.87246
16.0782 +0.3048
16.637 +0.14224
17.4625
3
1.27
17.4625 –0.20574
16.637 –0.08128
15.90548
16.0782 +0.2083
16.637 +0.10668
17.4625
62
11/16—24
UNEF
2
1.058333
17.43202 –0.18288
16.74368 –0.1016
16.13408
16.3068 +0.254
16.77416 +0.13208
17.4625
3
1.058333
17.4625 –0.18288
16.77416 –0.0762
16.16456
16.3068 +0.1880
16.77416 +0.09906
17.4625
63
11/16—28
UN
2
0.907143
17.43456 –0.1651
16.84528 –0.09652
16.32204
16.4846 +0.2032
16.87322 +0.12466
17.4625
3
0.907143
17.4625 –0.1651
16.87322 –0.07112
16.34998
16.4846 +0.1549
16.87322 +0.09398
17.4625
64
11/16—32
UN
2
0.79375
17.43456 –0.1524
16.91894 –0.09144
16.46174
16.6116 +0.1778
16.94688 +0.11684
17.4625
3
0.79375
17.4625 –0.1524
16.94688 –0.06858
16.48968
16.6116 +0.1372
16.94688 +0.0889
17.4625
65
3/4—10
UNC
1
2.54
19.00428 –0.49276
17.35328 –0.22352
15.8877
16.3068 +0.5334
17.399 +0.2921
19.05
2
2.54
19.00428 –0.32766
17.35328 –0.14986
15.8877
16.3068 +0.5334
17.399 +0.19558
19.05
3
2.54
19.05 –0.32766
17.399 –0.11176
15.93342
16.3068 +0.3175
17.399 +0.14478
19.05
66
3/4—12
UN
2
2.116667
19.00682 –0.28956
17.63268 –0.1397
16.41094
16.764 +0.4572
17.67586 +0.18288
19.05
3
2.116667
19.05 –0.28956
17.67586 –0.10414
16.45412
16.764 +0.27178
17.67586 +0.13716
19.05
67
3/4—16
UNF
1
1.5875
19.0119 –0.36068
17.98066 –0.1905
17.06372
17.3228 +0.3556
18.01876 +0.24892
19.05
2
1.5875
19.0119 –0.23876
17.98066 –0.127
17.06372
17.3228 +0.3556
18.01876 +0.1651
19.05
3
1.5875
19.05 –0.23876
18.01876 –0.09652
17.10182
17.3228 +0.2235
18.01876 +0.12446
19.05
68
3/4—20
UNEF
2
1.27
19.01698 –0.20574
18.19148 –0.11176
17.45996
17.6784 +0.2794
18.2245 +0.14478
19.05
3
1.27
19.05 –0.20574
18.2245 –0.08382
17.49298
17.6784 +0.1956
18.2245 +0.10922
19.05
序号
规格代号
系列代号
等级
螺距
外螺纹
内螺纹
名义直径 每英寸牙数
外径
中径
内径
小径
中径
大径
69
3/4—28
UN
2
0.907143
19.0195 –0.1651
18.43024 –0.09652
17.907
18.0594 +0.2286
18.46072 +0.127
19.05
3
0.907143
19.05 –0.1651
18.46072 –0.07366
17.93748
18.0594 +0.1676
18.46072 +0.09398
19.05
70
3/4—32
UN
2
0.79375
19.02206 –0.1524
18.50644 –0.09144
18.04924
18.1864 +0.2032
18.53438 +0.11938
19.05
3
0.79375
19.05 –0.1524
18.53438 –0.06858
18.07718
18.1864 +0.1499
18.53438 +0.09144
19.05
71
13/16—12
UN
2
2.116667
20.59432 –0.28956
19.22018 –0.1397
17.99844
18.3388 +0.4572
19.26336 +0.18288
20.6375
3
2.116667
20.6375 –0.28956
19.26336 –0.10414
18.04162
18.3388 +0.2769
19.26336 +0.13716
20.6375
72
13/16—16
UN
2
1.5875
20.5994 –0.23876
19.56816 –0.12446
18.65122
18.923 +0.3556
19.60626 +0.16002
20.6375
3
1.5875
20.6375 –0.23876
19.60626 –0.09144
18.68932
18.923 +0.21082
19.60626 +0.11938
20.6375
73
13/16—20
UNEF
2
1.27
20.60448 –0.20574
19.77898 –0.11176
19.04746
19.2532 +0.3048
19.812 +0.14478
20.6375
3
1.27
20.6375 –0.20574
19.812 –0.8382
19.08048
19.2532 +0.2083
19.812 +0.10922
20.6375
74
13/16—28
UN
2
0.907143
20.607 –0.1651
20.01774 –0.09652
19.4945
19.6596 +0.2032
20.04822 +0.127
20.6375
3
0.907143
20.6375 –0.1651
20.04822 –0.07366
19.52498
19.6596 +0.1549
20.04822 +0.09398
20.6375
75
13/16—32
UN
2
0.79375
20.60956 –0.1524
20.09394 –0.09144
19.63674
19.7866 +0.1778
20.12188 +0.11938
20.6375
3
0.79375
20.6375 –0.1524
20.12188 –0.06858
19.66468
19.7866 +0.1372
20.12188 +0.09144
20.6375
76
7/8—9
UNC
1
2.822222
22.17674 –0.52832
20.34286 –0.2413
18.71472
19.177 +0.5842
20.39112 +0.31242
22.225
2
2.822222
22.17674 –0.35306
20.34286 –0.16002
18.71472
19.177 +0.5842
20.39112 +0.20828
22.225
3
2.822222
22.225 –0.35306
20.39112 –0.11938
18.76298
19.177 +0.33274
20.39112 +0.15494
22.225
77
7/8—12
UN
2
2.116667
22.18182 –0.28956
20.80768 –0.1397
19.58594
19.939 +0.4572
20.85086 +0.18288
22.225
3
2.116667
22.225 –0.28956
20.85086 –0.10414
19.62912
19.939 +0.25908
20.85086 +0.13716
22.225
78
7/8—14
UNF
1
1.814286
22.18436 –0.3937
21.0058 –0.20574
19.95932
20.2692 +0.4064
21.04644 +0.26924
22.225
2
1.814286
22.18436 –0.26162
21.0058 –0.13716
19.95932
20.2692 +0.4064
21.04644 +0.1778
22.225
3
1.814286
22.225 –0.26162
21.04644 –0.10414
19.99996
20.2692 +0.2235
21.04644 +0.13462
22.225
79
7/8—16
UN
2
1.5875
22.1869 –0.23876
21.15566 –0.12446
20.23872
20.4978 +0.3556
21.19376 +0.16002
22.225
3
1.5875
22.225 –0.23876
21.19376 –0.09144
20.27682
20.4978 +0.2235
21.19376 +0.11938
22.225
80
7/8—20
UNEF
2
1.27
22.19198 –0.20574
21.36648 –0.11176
20.63496
20.8534 +0.2794
21.3995 +0.14478
22.225
3
1.27
22.225 –0.20574
21.3995 –0.08382
20.66798
20.8534 +0.1956
21.3995 +0.10922
22.225
准备攻丝的螺纹
钻头规格代码
(最接近的英制分数规格)
英制小数规格
公制尺寸
1/8"-27NPT
字母R
-
.3390
Ø8.61
1/4"-18NPT
7/16"
7/16"
.4375
Ø11.11
3/8"-18NPT
14.68
37/64"
.5781
Ø14.68
1/2"-14NPT
45/64"
45/64"
.7031
Ø17.85
3/4"-14NPT
59/64"
59/64"
.9219
Ø23.41
1"-11½ NPT
15/32"
15/32"
1.1562
Ø29.37
1¼"-11 ½ NPT
1½"
1½"
1.5000
Ø38.1
1½"-11 ½ NPT
147/64"
147/64"
1.7344
Ø44.05
2"-11½ NPT
27/32"
27/32"
2.2188
Ø56.35
牙形高度=D-d除2。这是单边量。
d的算法有很多种，根据不同的罗纹有不同的值。下面我给你具体分开来算：
1：公制螺纹d=D-1.0825乘P；
2：55度英制螺纹d=D-1.2乘P；
3：60度圆锥管螺纹d=D-1.6乘P；
4：55度圆锥管螺纹d=D-1.28乘P；
5：55度圆柱管螺纹d=D-1.3乘P；
6：60度米制锥螺纹d=D-1.3乘P；
注：d=螺纹小径，D=螺纹大径，P=螺距，H就是牙形高度
粗牙就是M+公称直径（也就是螺纹大径）。例如：M10，M16
细牙就是M+公称直径乘螺距。例如：M10X1，M20X1.5
当螺纹为左旋时，会标注“左”，右旋时不标注。
还有一种标注法：例如，M10——5g6g（这就是外螺纹），M10——6H（这就是内螺纹）
注:内外螺纹都是大径算小径.公式一样
英寸制统一螺纹，在英寸制国家广泛采用，该类螺纹分三个系列：粗牙系列UNC，细牙系列UNF，特细牙系列UNFF，外加一个定螺距系列UN。
标注方法：螺纹直径—每英寸牙数 系列代号—精度等级
示例：粗牙系列 3/8—16 UNC—2A
细牙系列 3/8—24 UNF—2A
特细牙系列 3/8—32 UNFF—2A
定螺距系列 3/8—20 UN—2A
第一位数字3/8表示螺纹外径，单位为英寸，转换为米制单位mm要乘以25.4，即3/8×25.4=9.525mm；第二、三位数字16、24、32、20为每英寸牙数(在25.4mm长度上的牙数)；第三位以后的文字代号UNC、UNF、UNFF、UN为系列代号，最后两位2A为精度等级。
螺纹配合等级：
三、螺纹配合是旋合螺纹之间松或紧的大小，配合的等级是作用在内外螺纹上偏差和公差的规定组合。
（一）、对统一英制螺纹，外螺纹有三种螺纹等级：1A、2A和3A级，内螺纹有三种等级：
1B、2B和3B级，全部都是间隙配合。等级数字越高，配合越紧。在英制螺纹中，偏差仅规定1A和2A级，3A级的偏差为零，而且1A和2A级的等级偏差是相等的。
1、1A和1B级，非常松的公差等级，其适用于内外螺纹的允差配合。
2、2A和2B级，是英制系列机械紧固件规定最通用的螺纹公差等级。
3、3A和3B级，旋合形成最紧的配合，适用于公差紧的紧固件，用于安全性的关键设计。
4、对外螺纹来说，1A和2A级有一个配合公差，3A级没有。1A级公差比2A级公差大50%，比3A级大75%，对内螺纹来说，2B级公差比2A公差大30%。1B级比2B级大50%，比3B级大75%。
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