The M8 size of Serrated Flange Lock Nuts is dimensioned by DIN 6923. The table below gives the dimensional row from the standard, followed by the drive and the installation notes for this type.
M8 Dimensional Row (DIN 6923)
| Thread size | Pitch (mm) | Across flats s (mm) | Flange diameter dc (mm) | Total height m (mm) | Flange thickness c (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M8 | 1.25 | 13 | 17.9 | 8.0 | 1.2 | DIN 6923 |
Spanner & Drive for M8 Serrated Flange Lock Nuts
Drive geometry for M8 Serrated Flange Lock Nuts is given by the row above; match the tool to the listed values.
Tightening Torque for M8
| Class 8.8 (dry, ~µ 0.125) | ≈ 25 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 35 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 41 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 M8
| Tensile stress area As (ISO 898-1) | 36.6 mm² |
|---|---|
| Proof load, class 8.8 | 21 kN |
| Proof load, class 10.9 | 30 kN |
| Proof load, class 12.9 | 36 kN |
| Min. ultimate tensile, class 8.8 | 29 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 M8 Serrated Flange Lock Nuts
M8 Serrated Flange Lock Nuts are commonly specified for general-purpose joints in machinery, fixturing and equipment frames.
Mating Parts for M8
Pair M8 with the matching M8 bolt or screw, plus a M8 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M8
When the joint preload approaches the proof load of M8 class 8.8, step up to M10 class 8.8 (or move to M8 class 10.9). When the joint is over-specified, M6 often saves weight and cost without losing the safety margin.
