Bolt Thread Size Chart
Size |
Threads Per Inch |
Class Thread |
Major Diameter |
Max. |
Min. |
Pitch Diameter |
Max. |
Min. |
Minor Diameter |
1/4
20
28
2A
2A
0.2489
0.2490
0.2408
0.2425
0.2164
0.2258
0.2127
0.2225
0.1876
0.2052
5/16
18
24
2A
2A
0.3113
0.3114
0.3026
0.3042
0.2752
0.2843
0.2712
0.2806
0.2431
0.2603
3/8
16
24
2A
2A
0.3737
0.3739
0.3643
0.3667
0.3331
0.3468
0.3287
0.3430
0.2970
0.3228
7/16
14
20
2A
2A
0.4361
0.4362
0.4258
0.4281
0.3897
0.4237
0.3850
0.3995
0.3485
0.3749
1/2
13
20
2A
2A
0.4985
0.4987
0.4876
0.4906
0.4485
0.4662
0.4435
0.4619
0.4041
0.4374
9/16
12
18
2A
2A
0.5609
0.5611
0.5495
0.5524
0.5068
0.5250
0.5016
0.5205
0.4587
0.4929
5/8
11
18
2A
2A
0.6234
0.6236
0.6113
0.6149
0.5644
0.5875
0.5589
0.5828
0.5119
0.5449
3/4
10
16
2A
2A
0.7482
0.7485
0.7353
0.7391
0.6832
0.7079
0.6773
0.7029
0.6255
0.6718
7/8
9
14
2A
2A
0.8731
0.8734
0.8592
0.8631
0.8009
0.8270
0.7946
0.8216
0.7368
0.7858
1
8
12
2A
2A
0.9980
0.9982
0.9830
0.9868
0.9168
0.9441
0.9100
0.9382
0.8446
0.8960