ISO 4017 Hexagon head screws – Basic dimensions
Selected sizes used for CE (UKCA) Marking under BS EN 15048
| Diameter (d) |
M12 | M16 | M20 | M22 | M24 | M27 | M30 | M33 | M36 |
|---|---|---|---|---|---|---|---|---|---|
| Thread pitch (P) |
1.75 | 2 | 2.5 | 2.5 | 3 | 3 | 3.5 | 3.5 | 4 |
| k (nom) |
7.5 | 10 | 12.5 | 14 | 15 | 17 | 18.7 | 21 | 22.5 |
| k (Grade A) |
7.32-7.68 | 9.82-10.18 | 12.285-12.715 | 13.785-14.215 | 14.785-15.215 | – | – | – | – |
| k (Grade B) |
7.21-7.79 | 9.71-10.29 | 12.15-12.85 | 13.65-14.35 | 14.65-15.35 | 16.65-17.35 | 18.28-19.12 | 20.58-21.42 | 22.08-22.92 |
| s (nom) |
18 | 24 | 30 | 34 | 36 | 41 | 46 | 50 | 55 |
| s (min, Grade A) |
17.73 | 23.67 | 29.67 | 33.38 | 35.38 | – | – | – | – |
| s (min, Grade B) |
17.57 | 23.16 | 29.16 | 33.00 | 35.00 | 40.00 | 45.00 | 49.00 | 63.10 |
| e (min, Grade A) |
20.03 | 26.75 | 33.53 | 37.72 | 39.98 | – | – | – | – |
| e (min, Grade B) |
19.85 | 26.17 | 32.95 | 37.29 | 39.55 | 45.20 | 50.85 | 55.37 | 60.79 |
Dimensions in millimetres
| Size | Grade A | Grade B |
|---|---|---|
| M12 (l) | Up and including 120 | Including and above 125 |
| M16 (l) | Up and including 150 | Including and above 155 |
| M20 (l) | Up and including 150 | Including and above 155 |
| M22 (l) | Up and including 150 | Including and above 155 |
| M24 (l) | Up and including 150 | Including and above 155 |
| M27 (l) | – | All lengths |
| M30 (l) | – | All lengths |
| M33 (l) | – | All lengths |
| M36 (l) | – | All lengths |
Whilst the information is provided in good faith, Andrews Fasteners Ltd are not under any responsibility or liability in respect of errors or information that was found to be incorrect or for any reliance the user may place on it.