DIN 931 Hex Head Bolts
M4 - M48
High tensile 8.8Grade 10.9Grade 12.9Stainless steel A2Stainless steel A4
≡ ISO 4014
We supply DIN 931 part-threaded hex head bolts in high tensile steel grades 8.8, 10.9 and 12.9 and stainless steel A2 and A4, from M4 to M48. The plain shank below the head locates the joint and carries shear better than a fully threaded fastener, which makes DIN 931 the default bolt for structural and machinery joints where the joint plane falls on the shank.
Also known as: hex bolt, hexagon head bolt, part threaded bolt, hexagon bolt, HT bolt.
DIN 931 dimensions
| Diameter | Pitch | Thread length (b) | Head depth (k) | Across flats (s) |
|---|---|---|---|---|
| M41 | 0.7 mm | 14 mm | 2.8 mm | 7 mm |
| M5 | 0.8 mm | 16 mm | 3.5 mm | 8 mm |
| M6 | 1.0 mm | 18 mm | 4.0 mm | 10 mm |
| M7 | 1.0 mm | 20 mm | 4.8 mm | 11 mm |
| M8 | 1.25 mm | 22 mm | 5.3 mm | 13 mm |
| M10 | 1.5 mm | 26 mm | 6.4 mm | 17 mm |
| M12 | 1.75 mm | 30 mm | 7.5 mm | 19 mm |
| M14 | 2.0 mm | 34 mm | 8.8 mm | 22 mm |
| M16 | 2.0 mm | 38 mm | 10 mm | 24 mm |
| M18 | 2.5 mm | 42 mm | 11.5 mm | 27 mm |
| M20 | 2.5 mm | 46 mm | 12.5 mm | 30 mm |
| M22 | 2.5 mm | 50 mm | 14 mm | 32 mm |
| M24 | 3.0 mm | 54 mm | 15 mm | 36 mm |
| M27 | 3.0 mm | 60 mm | 17 mm | 41 mm |
| M30 | 3.5 mm | 66 mm | 18.7 mm | 46 mm |
| M33 | 3.5 mm | 72 mm | 21 mm | 50 mm |
| M36 | 4.0 mm | 78 mm | 22.5 mm | 55 mm |
| M39 | 4.0 mm | 84 mm | 25 mm | 60 mm |
| M42 | 4.5 mm | 90 mm | 26 mm | 65 mm |
| M45 | 4.5 mm | 96 mm | 28 mm | 70 mm |
| M48 | 5.0 mm | 102 mm | 30 mm | 75 mm |
- Thread lengths are a guide for bolts under 125mm. For bolts over 125mm and up to 200mm add 6mm; for bolts 200mm and longer add 19mm.
Need DIN 931 in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.