M6 Hex Nut are manufactured to GB/T 6170 / ISO 4032. This page lists the controlling dimensions for the M6 size together with the drive and the installation notes for this type.
M6 Dimensional Row (GB/T 6170 / ISO 4032)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Nut height m (mm) | Reference standard |
|---|---|---|---|---|---|
| M6 | 1.0 | 10.0 | 11.05 | 5.2 | ISO 4032 / GB/T 6170 |
Spanner & Drive for M6 Hex Nut — GB/T 6170 / ISO 4032 (Series 066)
M6 Hex Nut — GB/T 6170 / ISO 4032 (Series 066) have a width across flats of 10.0 mm — fit a 10.0 mm open-ended spanner or socket. Use a 6-point socket for tight clearances and to reduce rounding; for repeated assembly choose a torque wrench so the joint preload is repeatable.
Tightening Torque for M6
| Class 8.8 (dry, ~µ 0.125) | ≈ 10 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 14 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 17 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 M6
| Tensile stress area As (ISO 898-1) | 20.1 mm² |
|---|---|
| Proof load, class 8.8 | 12 kN |
| Proof load, class 10.9 | 17 kN |
| Proof load, class 12.9 | 19 kN |
| Min. ultimate tensile, class 8.8 | 16 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 M6 Hex Nut — GB/T 6170 / ISO 4032 (Series 066)
M6 Hex Nut — GB/T 6170 / ISO 4032 (Series 066) are commonly specified for general-purpose joints in machinery, fixturing and equipment frames.
Mating Parts for M6
Pair M6 with the matching M6 bolt or screw, plus a M6 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M6
When the joint preload approaches the proof load of M6 class 8.8, step up to M8 class 8.8 (or move to M6 class 10.9). When the joint is over-specified, M5 often saves weight and cost without losing the safety margin.


