The M30 size of Hexagon Coupling Nuts is dimensioned by DIN 6334. The table below gives the dimensional row from the standard, followed by the drive and the installation notes for this type.
M30 Dimensional Row (DIN 6334)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Length l (mm) | Reference standard |
|---|---|---|---|---|---|
| M30 | 3.5 | 46 | 50.85 | 90 | DIN 6334 |
Spanner & Drive for M30 Hexagon Coupling Nuts
Drive geometry for M30 Hexagon Coupling Nuts is given by the row above; match the tool to the listed values.
Tightening Torque for M30
| Class 8.8 (dry, ~µ 0.125) | ≈ 1400 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 2000 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 2400 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M30
| Tensile stress area As (ISO 898-1) | 561 mm² |
|---|---|
| Proof load, class 8.8 | 337 kN |
| Proof load, class 10.9 | 466 kN |
| Proof load, class 12.9 | 544 kN |
| Min. ultimate tensile, class 8.8 | 449 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
Common Applications for M30 Hexagon Coupling Nuts
M30 Hexagon Coupling Nuts are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M30 Hexagon Coupling Nuts
- At M30 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M30
Pair M30 with the matching M30 bolt or screw, plus a M30 flat washer where required to distribute load on softer materials.

