JIS E 1107 – 2008 – Bu lông đầu vuông

| Part No. | A50 | B50 | B40N | B50N | B60 | |
| d | Nominal Diameter | M24 | M24 | M20 | M20 | M20 |
| s | max | 50.5 | 50.5 | 42.5 | 42.5 | 42.5 |
| min | 49.5 | 49.5 | 41.5 | 41.5 | 41.5 | |
| s1 | 25 | 25 | 20 | 20 | 20 | |
| k | max | 16.5 | 16.5 | 14.5 | 14.5 | 14.5 |
| min | 15.5 | 15.5 | 13.5 | 13.5 | 13.5 | |
| h | 8 | 8 | 7 | 7 | 7 | |
| b | max | 71 | 71 | 51 | 51 | 61 |
| min | 65 | 65 | 45 | 45 | 55 | |


