DIN 931 dimensions — Hex Head Bolt, Partially Threaded
1987, replaced by ISO 4014 · 22 sizes, M1.6 – M36 · 8 of 88 recorded values differ, marked below →
✓We supply to both. Name either on your order.
DIN 931 dimensions
| Thread size | PThread Pitch (mm) | sWidth Across Flats (max) (mm) | eWidth Across Corners (min) (mm) | kNominal Head Height (mm) | bThread Length (L <= 125) (mm) | bThread Length (125 < L <= 200) (mm) | bThread Length (L > 200) (mm) | Clearance holefine / medium / coarse (mm) | Tap drillcoarse pitch (mm) |
|---|---|---|---|---|---|---|---|---|---|
| M1.6 | 0.35 | 3.2 | 3.41 | 1.1 | 9 | 15 | 28 | 1.7 / 1.8 / 2 | 1.25 |
| M2 | 0.4 | 4 | 4.32 | 1.4 | 10 | 16 | 29 | 2.2 / 2.4 / 2.6 | 1.6 |
| M2.5 | 0.45 | 5 | 5.45 | 1.7 | 11 | 17 | 30 | 2.7 / 2.9 / 3.1 | 2.05 |
| M3 | 0.5 | 5.5 | 6.01 | 2 | 12 | 18 | 31 | 3.2 / 3.4 / 3.6 | 2.5 |
| M3.5 | 0.6 | 6 | 6.58 | 2.4 | 13 | 19 | 32 | 3.7 / 3.9 / 4.2 | 2.9 |
| M4 | 0.7 | 7 | 7.66 | 2.8 | 14 | 20 | 33 | 4.3 / 4.5 / 4.8 | 3.3 |
| M5 | 0.8 | 8 | 8.79 | 3.5 | 16 | 22 | 35 | 5.3 / 5.5 / 5.8 | 4.2 |
| M6 | 1 | 10 | 11.05 | 4 | 18 | 24 | 37 | 6.4 / 6.6 / 7 | 5 |
| M7 | 1 | 11 | 12.12 | 4.8 | 20 | 26 | 39 | 7.4 / 7.6 / 8 | 6 |
| M8 | 1.25 | 13 | 14.38 | 5.3 | 22 | 28 | 41 | 8.4 / 9 / 10 | 6.8 |
| M10 | 1.5 | 17ISO 4014: 16 | 18.9ISO 4014: 17.77 | 6.4 | 26 | 32 | 45 | 10.5 / 11 / 12 | 8.5 |
| M12 | 1.75 | 19ISO 4014: 18 | 21.1ISO 4014: 20.03 | 7.5 | 30 | 36 | 49 | 13 / 13.5 / 14.5 | 10.2 |
| M14 | 2 | 22ISO 4014: 21 | 24.49ISO 4014: 23.36 | 8.8 | 34 | 40 | 53 | 15 / 15.5 / 16.5 | 12 |
| M16 | 2 | 24 | 26.75 | 10 | 38 | 44 | 57 | 17 / 17.5 / 18.5 | 14 |
| M18 | 2.5 | 27 | 30.14 | 11.5 | 42 | 48 | 61 | 19 / 20 / 21 | 15.5 |
| M20 | 2.5 | 30 | 33.53 | 12.5 | 46 | 52 | 65 | 21 / 22 / 24 | 17.5 |
| M22 | 2.5 | 32ISO 4014: 34 | 35.72ISO 4014: 37.72 | 14 | 50 | 56 | 69 | 23 / 24 / 26 | 19.5 |
| M24 | 3 | 36 | 39.98 | 15 | 54 | 60 | 73 | 25 / 26 / 28 | 21 |
| M27 | 3 | 41 | 45.2 | 17 | 60 | 66 | 79 | 28 / 30 / 32 | 24 |
| M30 | 3.5 | 46 | 50.85 | 18.7 | 66 | 72 | 85 | 31 / 33 / 35 | 26.5 |
| M33 | 3.5 | 50 | 55.37 | 21 | 72 | 78 | 91 | 34 / 36 / 38 | 29.5 |
| M36 | 4 | 55 | 60.79 | 22.5 | - | 84 | 97 | 37 / 39 / 42 | 32 |
22 of 22 sizes shown. Clearance holes are fine / medium / coarse to ISO 273; tap drill is for the coarse pitch. Amber values are ISO 4014.
What we supply to DIN 931
3 materials| Material | Property class | Finish |
|---|---|---|
| Carbon Steel | 4.8 · 8.8 | Plain · Zinc Plated · Dacromet · Blackened · Phosphate · Hot Dip Galvanized |
| Alloy Steel | 10.9 | Plain · Zinc Plated · Dacromet · Blackened · Phosphate |
| Stainless Steel | A2-70 · A4-80 | Passivated · Plain |
Property classes
ISO 898-1 · ISO 3506-1| Class | Rm min. | Yield requirement | Elongation requirement | Hardness | Typical use |
|---|---|---|---|---|---|
| A2-70 | 700 MPa | Rp0.2 min. 450 MPa | 0,4d mm | - | Cold-worked austenitic stainless, typically 304 — outdoor, wet and food service away from chlorides. |
| A4-80 | 800 MPa | Rp0.2 min. 600 MPa | 0,3d mm | - | The strongest 316-type class; marine and chemical service where 70 does not carry the load. |
| 4.8 | 420 MPa | Rpf min. 340 MPa (not a test value) | Af min. 0.24 | 130 - 220 HV | Light-duty non-structural work; the low-cost class for large sizes carrying little load. |
| 8.8 (d <= M16) | 800 MPa | Rp0.2 min. 640 MPa | A min. 12 % | 250 - 320 HV | The general-purpose structural class — steel-to-steel joints, machinery, vehicle assembly. Assume this if no class is stated. |
| 8.8 (d > M16) | 830 MPa | Rp0.2 min. 660 MPa | A min. 12 % | 255 - 335 HV | |
| 10.9 | 1040 MPa | Rp0.2 min. 940 MPa | A min. 9 % | 320 - 380 HV | Preloaded high-tension joints — engine, gearbox and structural connections that grip by friction. Needs controlled tightening. |
These values meet the requirements of ISO 3506-1 / ISO 898-1. We supply to these classes and issue the matching mill certificate and third-party test report with your order.
