DIN 261 dimensions — T-head bolts
2024-12 edition, current · 16 sizes, M8 – M100 see the cross-reference →
✓We supply to DIN 261. Name it on your order.
DIN 261 dimensions
| Thread size | PThread Pitch (mm) | bThread Length (L ≤ 120) (mm) | bThread Length (120 < L ≤ 200) (mm) | bThread Length (L > 200) (mm) | dₛBody Diameter (max) (mm) | dₛBody Diameter (min) (mm) | kHead Height (max) (mm) | kHead Height (min) (mm) | nHead Thickness (max) (mm) | nHead Thickness (min) (mm) | mHead Width (max) (mm) | mHead Width (min) (mm) | r_min~Minimum Radius (approx.) (mm) | daUnderhead Diameter (max) (mm) | d₂Internal Thread | t₁Internal Thread Length (mm) | Clearance holefine / medium / coarse (mm) | Tap drillcoarse pitch (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M8 | 1.25 | 22 | - | - | 8.58 | 7.42 | 5.9 | 5.1 | 8.75 | 7.25 | 18.9 | 17.1 | 0.4 | 10.2 | - | - | 8.4 / 9 / 10 | 6.8 |
| M10 | 1.5 | 26 | - | - | 10.58 | 9.42 | 7.5 | 6.5 | 10.75 | 9.25 | 22 | 20 | 0.4 | 12.2 | - | - | 10.5 / 11 / 12 | 8.5 |
| M12 | 1.75 | 30 | - | - | 12.7 | 11.3 | 8.75 | 7.25 | 12.9 | 11.1 | 27 | 25 | 0.6 | 14.7 | - | - | 13 / 13.5 / 14.5 | 10.2 |
| M16 | 2 | 38 | 44 | 57 | 16.7 | 15.3 | 11.4 | 9.6 | 16.9 | 15.1 | 31 | 29 | 0.6 | 18.7 | - | - | 17 / 17.5 / 18.5 | 14 |
| M20 | 2.5 | 46 | 52 | 65 | 20.84 | 19.16 | 13.9 | 12.1 | 21 | 19 | 37.25 | 35.75 | 0.8 | 24.4 | - | - | 21 / 22 / 24 | 17.5 |
| M24 | 3 | 54 | 60 | 73 | 24.84 | 23.16 | 15.9 | 14.1 | 25 | 23 | 44.25 | 41.75 | 0.8 | 28.4 | - | - | 25 / 26 / 28 | 21 |
| M30 | 3.5 | 66 | 72 | 85 | 30.84 | 29.16 | 20 | 18 | 31 | 29 | 55.5 | 52.5 | 1 | 35.4 | - | - | 31 / 33 / 35 | 26.5 |
| M36 | 4 | 78 | 84 | 97 | 37 | 35 | 24 | 22 | 37.25 | 34.75 | 67.5 | 64.5 | 1 | 42.4 | M12 | 22 | 37 / 39 / 42 | 32 |
| M42 | 4.5 | 90 | 96 | 109 | 34 | 33 | 27 | 25 | 43.25 | 40.75 | 81.5 | 78.5 | 1.2 | 48.6 | M12 | 22 | 43 / 45 / 48 | 37.5 |
| M48 | 5 | - | 108 | 121 | 38 | 37 | 31 | 29 | 49.25 | 46.75 | 89.75 | 86.25 | 1.6 | 56.6 | M12 | 22 | 50 / 52 / 56 | 43 |
| M56 | 5.5 | - | 124 | 137 | 45 | 44 | 36.25 | 33.75 | 57.5 | 54.5 | 103.75 | 100.25 | 2 | 67 | M16 | 26 | 58 / 62 / 66 | 50.5 |
| M64 | 6 | - | 130 | 143 | 50 | 49 | 41.25 | 38.75 | 65.5 | 62.5 | 116.75 | 113.25 | 2 | 75 | M16 | 26 | 66 / 70 / 74 | - |
| M72 | 6 | - | - | 169 | 55 | 53.8 | 46.25 | 43.75 | 73.5 | 70.5 | 130 | 126 | 2 | 83 | M16 | 26 | 74 / 78 / 82 | - |
| M80 | 6 | - | - | 185 | 65 | 63.8 | 51.25 | 48.75 | 81.5 | 78.5 | 142 | 138 | 2 | 92 | M20 | 33 | 82 / 86 / 91 | - |
| M90 | 6 | - | - | 205 | 70 | 68.8 | 56.5 | 53.5 | 91.75 | 88.25 | 157 | 153 | 2.5 | 102 | M20 | 33 | 93 / 96 / 101 | - |
| M100 | 6 | - | - | 225 | 80 | 78.8 | 63.5 | 60.5 | 101.75 | 98.25 | 172 | 168 | 2.5 | 113 | M20 | 33 | 104 / 107 / 112 | - |
16 of 16 sizes shown. Clearance holes are fine / medium / coarse to ISO 273; tap drill is for the coarse pitch.
DIN 261 sizes
3 diameters · weight and hole sizes live on each size pageWhat we supply to DIN 261
2 materials| Material | Property class | Finish |
|---|---|---|
| Carbon Steel | 8.8 | Zinc Plated |
| Stainless Steel | A2-70 · A4-80 | Plain · Passivated |
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. |
| 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 |
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.
