Imperial Hex Head Bolt Specifications
- B Measurement varies according to the length of bolt
- All measurements are in millimeters (mm)
- For Hex Set Screws disregard B measurement as they are fully threaded
ANSI B18.2.1 Specifications
| D |
B to 6" |
B over 6" |
K |
S |
| 1/4 |
19.05 |
25.4 |
4.14 |
11.13 |
| 5/16 |
22.22 |
28.57 |
5.36 |
12.70 |
| 3/8 |
25.4 |
31.75 |
6.17 |
14.27 |
| 7/16 |
28.57 |
34.9 |
7.39 |
15.90 |
| 1/2 |
31.75 |
38.1 |
8.20 |
19.05 |
| 5/8 |
38.1 |
44.5 |
10.24 |
23.83 |
| 3/4 |
44.45 |
50.8 |
12.27 |
28.58 |
| 7/8 |
50.8 |
57.15 |
14.30 |
33.32 |
| 1" |
57.15 |
63.50 |
15.92 |
38.1 |
BS1083 Specifications
| D |
B to 6" |
B over 6" |
K |
S |
| 1/4 |
19.05 |
25.4 |
4 |
10 |
| 5/16 |
22.24 |
28.57 |
5 |
12 |
| 3/8 |
25.4 |
31.75 |
5.55 |
14 |
| 7/16 |
28.57 |
34.93 |
7 |
17 |
| 1/2 |
31.75 |
38.1 |
7.65 |
19 |
| 5/8 |
38.10 |
44.5 |
9.35 |
23 |
* Use this information as a guide only
