DIN 7991 (ISO 10642) defines countersunk head bolts with an internal hex socket (Allen). These bolts provide a flat and clean mounting surface as their heads sit flush with the surface. The Allen head design allows easy tightening with hex keys and is ideal for precision applications. DIN 7991 bolts are commonly used in mechanical engineering and metal connections, especially in areas requiring a low-profile and aesthetic appearance. Made from stainless steel or steel, they are available in various sizes and materials.
| Boy/ Ø | M3 | M4 | M5 | M6 | M8 | M10 | M12 | M16 | M20 |
|---|---|---|---|---|---|---|---|---|---|
| dk | 6 | 8 | 10 | 12 | 16 | 20 | 24 | 30 | 36 |
| k | 1,7 | 2,3 | 2,8 | 3,3 | 4,4 | 5,5 | 6,5 | 7,5 | 8,5 |
| s | 2,0 | 2,5 | 3,0 | 4,0 | 5,0 | 6,0 | 8,0 | 10,0 | 12,0 |
| b | 12 | 14 | 16 | 18 | 22 | 26 | 30 | 38 | 46 |
| t | 1,2 | 1,8 | 2,3 | 2,5 | 3,5 | 4,4 | 4,6 | 5,3 | 5,9 |
| e | 2,30 | 2,87 | 3,44 | 4,58 | 5,72 | 6,86 | 9,15 | 11,43 | 13,72 |
| ⬢ | 2,0 | 2,5 | 3,0 | 4,0 | 5,0 | 6,0 | 8,0 | 10,0 | 12,0 |