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