Unified
External Screw Threads
Data for machine screws, threaded fasteners and industrial fasteners from Elgin Fastener Group includes unified external screw threads. Diameters and sizes for class 2A and 3A UNRC. and UNRF. and ISO metric threads are listed in the chart below.
|
Classes
2A & 3A UNRC. UNRF.
|
|
Nominal
Size & TPI |
Class
2A |
Class
3A |
|
Major
Diameter |
Pitch
Diameter |
Major
Diameter |
Pitch
Diameter |
Blank
Size |
|
4-40 |
.1061
.1112 |
.0925
.0950 |
.1069
.1120 |
.0939
.0958 |
.0938
.0943 |
|
4-48 |
.1068
.1113 |
.0954
.0978 |
.1075
.1120 |
.0967
.0985 |
.0968
.0971 |
|
5-40 |
.1191
.1242 |
.1054
.1080 |
.1199
.1250 |
.1060
.1088 |
.1067
.1072 |
|
5-44 |
.1195
.1243 |
.1070
.1095 |
.1202
.1250 |
.1083
.1102 |
.1083
.1088 |
|
6-32 |
.1312
.1372 |
.1141
.1169 |
.1320
.1380 |
.1156
.1177 |
.1155
.1161 |
|
6-40 |
.1321
.1372 |
.1184
.1210 |
.1329
.1380 |
.1198
.1218 |
.1197
.1202 |
|
8-32 |
.1571
.1631 |
.1399
.1428 |
.1580
.1640 |
.1415
.1437 |
.1414
.1419 |
|
8-36 |
.1577
.1632 |
.1424
.1452 |
.1585
.1640 |
.1439
.1460 |
.1438
.1444 |
|
10-24 |
.1818
.1890 |
.1586
.1619 |
.1828
.1900 |
.1604
.1629 |
.1603
.1609 |
|
10-32 |
.1831
.1891 |
.1658
.1688 |
.1840
.1900 |
.1674
.1697 |
.1673
.1679 |
|
12-24 |
.2078
.2150 |
.1845
.1879 |
.2088
.2160 |
.1863
.1889 |
.1862
.1867 |
|
12-28 |
.2085
.2150 |
.1888
.1918 |
.2095
.2160 |
.1904
.1928 |
.1903
.1908 |
|
1/4-20 |
.2408
.2489 |
.2127
.2164 |
.2419
.2500 |
.2147
.2175 |
.2146
.2153 |
|
1/4-28 |
.2425
.2490 |
.2225
.2258 |
.2435
.2500 |
.2243
.2268 |
.2242
.2248 |
|
5/16-18 |
.3026
.3113 |
.2712
.2752 |
.3038
.3125 |
.2734
.2764 |
.2732
.2740 |
|
5/16-24 |
.3042
.3114 |
.2806
.2843 |
.3053
.3125 |
.2827
.2854 |
.2825
.2832 |
|
3/8-16 |
.3643
.3737 |
.3287
.3331 |
.3656
.3750 |
.3311
.3344 |
.3309
.3318 |
|
3/8-24 |
.3667
.3739 |
.3430
.3468 |
.3678
.3750 |
.3450
.3479 |
.3449
.3457 |
|
7/16-14 |
.4258
.4361 |
.3850
.3897 |
.4272
.4375 |
.3876
.3911 |
.3874
.3883 |
|
7/16-20 |
.4281
.4362 |
.3995
.4037 |
.4294
.4375 |
.4019
.4050 |
.4016
.4024 |
|
1/2-13 |
.4876
.4985 |
.4435
.4485 |
.4891
.5000 |
.4463
.4500 |
.4480
.4470 |
|
1/2-20 |
.4906
.4987 |
.4619
.4662 |
.4919
.5000 |
.4643
.4675 |
.4641
.4649 |
|
9/16-12 |
.5016
.5068 |
.5495
.5609 |
.5045
.5084 |
.5511
.5625 |
.5050
.5070 |
|
9/16-18 |
.5205
.5250 |
.5524
.5611 |
.523
.5264 |
.5538
.5625 |
.5170
.5190 |
|
5/8-11 |
.5589
.5644 |
.6113
.6234 |
.5619
.5660 |
.6129
.6250 |
.5630
.5650 |
| 5/8-18 |
.5828
.5875 |
.6149
.6236 |
.5854
.5889 |
.6163
.6250 |
.5840
.5860 |
|
ISO
Metric Threads — CLASS 6g
|
|
Metric
Size |
Inch
Measurement |
Millimeters |
|
Nominal
Size |
Major
Diameter |
Pitch
Diameter |
Blank
Size |
Major
Diameter |
Pitch
Diameter |
Blank
Size |
|
M3
x .5 |
.1173
.1131 |
.1045
.1016 |
.1037
.1030 |
2.980
2.874 |
2.655
2.580 |
2.635
2.615 |
|
M3.5
x .6 |
.1370
.1320 |
.1216
.1183 |
.1205
.1195 |
3.479
3.354 |
3.089
3.004 |
3.060
3.035 |
|
M4
x .7 |
.1566
.1511 |
.1387
.1352 |
.1376
.1364 |
3.978
3.938 |
3.523
3.438 |
3.495
3.465 |
|
M5
x .8 |
.1959
.1900 |
.1754
.1717 |
.1742
.1730 |
4.976
4.826 |
4.456
4.361 |
4.425
4.395 |
|
M6
x 1.0 |
.2352
.2281 |
.2096
.2052 |
.2087
.2071 |
5.974
5.794 |
5.324
5.212 |
5.300
5.260 |
|
M7
x 1.0 |
.2746
.2675 |
.2490
.2446 |
.2480
.2465 |
6.974
6.794 |
6.324
6.212 |
6.300
6.260 |
|
M8
x 1.25 |
.3139
.3055 |
.2819
.2772 |
.2807
.2791 |
7.972
7.760 |
7.160
7.042 |
7.130
7.090 |
|
M10
x 1.25 |
.3926
.3856 |
.3606
.3560 |
.3594
.3579 |
9.972
9.794 |
9.160
9.042 |
9.130
9.090 |
|
M10
x 1.5 |
.3924
.3831 |
.3541
.3489 |
.3528
.3512 |
9.968
9.732 |
8.994
8.862 |
8.960
8.920 |
|
M11
x 1.5 |
.4318
.4225 |
.3935
.3883 |
.3921
.3902 |
10.968
10.732 |
9.994
9.862 |
9.960
9.910 |
|
M12
x 1.25 |
.4713
.4630 |
.4394
.4342 |
.4382
.4366 |
11.972
11.760 |
11.160
11.028 |
11.130
11.090 |
| M12
x 1.75 |
.4711
.4607 |
.4263
.4204 |
.4252
.4232 |
11.966
11.701 |
10.829
10.679 |
10.800
10.750 |
ISO
Metric Threads — CLASS 4h |
|
Metric
Size |
Inch
Measurement |
Millimeters |
|
Nominal
Size |
Major
Diameter |
Pitch
Diameter |
Blank
Size |
Major
Diameter |
Pitch
Diameter |
Blank
Size |
|
M3
x .5 |
.1181
.1155 |
.1053
.1034 |
.1051
.1046 |
3.000
2.933 |
2.675
2.627 |
2.669
2.656 |
|
M3.5
x .6 |
.1378
.1321 |
.1216
.1183 |
.1212
.1205 |
3.500
3.355 |
3.088
3.004 |
3.078
3.060 |
|
M4
x .7 |
.1575
.1539 |
.1396
.1374 |
.1394
.1387 |
4.000
3.910 |
3.545
3.489 |
3.540
3.522 |
|
M5
x .8 |
.1968
.1931 |
.1751
.1740 |
.1748
.1741 |
5.000
4.905 |
4.480
4.420 |
4.439
4.422 |
|
M6
x 1.0 |
.2362
.2318 |
.2106
.2078 |
.2100
.2093 |
6.000
5.888 |
5.350
5.279 |
5.334
5.316 |
|
M7
x 1.0 |
.2756
.2712 |
.2500
.2472 |
.2494
.2487 |
7.000
6.888 |
6.350
6.279 |
6.334
6.316 |
|
M8
x 1.25 |
.3150
.3098 |
.2830
.2800 |
.2826
.2819 |
8.000
7.868 |
7.188
7.113 |
7.178
7.160 |
|
M10
x 1.0 |
.3937
.3893 |
.3681
.3653 |
.3675
.3668 |
10.000
9.888 |
9.350
9.279 |
9.334
8.554 |
|
M10
x 1.25 |
.3937
.3885 |
.3617
.3588 |
.3610
.3603 |
10.000
9.868 |
9.188
9.113 |
9.169
9.151 |
|
M10
x 1.5 |
.3937
.3878 |
.3553
.3520 |
.3551
.3544 |
10.000
9.850 |
9.026
8.941 |
9.020
9.001 |
|
M12
x 1.25 |
.4724
.4672 |
.4405
.4371 |
.4397
.4390 |
12.000
11.868 |
11.188
11.103 |
11.168
11.150 |
|
M12
x 1.5 |
.4724
.4665 |
.4341
.4305 |
.4335
.4328 |
12.000
11.850 |
11.026
10.936 |
11.010
10.993 |
|
M12
x 1.75 |
.4724
.4657 |
.4277
.4239 |
.4273
.4265 |
12.000
11.830 |
10.863
10.768 |
10.853
10.833 |
Torque Tensioning
Screw Point Types
Pilot Hole Sizes
Bolt & Screw Head Types
Weights per Thousand
Unified External Screw Threads
Rod & Bolt Diameters
Metric Conversions
Hole Sizes for Die Casting
Material Strength
Drive Tool Sizes
Hardness Conversions
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