British Associated British Standard Whitworth British Standard Fine
B.A.
| No. |
Dia. of Bolt |
No of threads per inch |
| 0 |
.2362 |
25.4 |
| 1 |
.2087 |
28.2 |
| 2 |
.1850 |
31.4 |
| 3 |
.1614 |
34.8 |
| 4 |
.1417 |
38.5 |
| 5 |
.1260 |
43.0 |
| 6 |
.1102 |
47.9 |
| 7 |
.0984 |
52.9 |
| 8 |
.0866 |
59.1 |
| 9 |
.0748 |
65.1 |
| 10 |
.0669 |
72.6 |
| 11 |
.0591 |
81.9 |
| 12 |
.0511 |
90.9 |
| 13 |
.0472 |
102.0 |
| 14 |
.0394 |
109.9 |
| 15 |
.0354 |
120.5 |
| 16 |
.0311 |
133.3 |
B.S.W.
| Diameter |
No of threads per inch. |
| 1/4 in. |
20 |
| 5/16 in. |
18 |
| 3/8 in. |
16 |
| 7/16 in. |
14 |
| 1/2 in. |
12 |
| 9/16 in. |
12 |
| 5/8 in. |
11 |
| 11/16 in. |
11 |
| 3/4 in. |
10 |
| 13/16 |
10 |
| 7/8 |
9 |
| 15/16 |
9 |
| 1 in. |
8 |
B.S.F.
| Diameter |
No of threads per inch |
| 7/32 in. |
28 |
| 1/4 in. |
26 |
| 9/32 in. |
26 |
| 5/16 in. |
22 |
| 3/8 in. |
20 |
| 7/16 in. |
18 |
| 1/2 in. |
16 |
| 9/16 in. |
16 |
| 5/8 in. |
14 |
| 11/16 in. |
14 |
| 3/4 in. |
12 |
| 13/16 in. |
12 |
| 7/8 in. |
11 |
| 1 in. |
10 |
| 1-1/8 in. |
9 |
| 1-1/4 in. |
9 |
| 1-3/8 in. |
8 |
| 1-1/2 in. |
8 |
| 1-5/8 in. |
8 |
