The M5 size of Hex Nut is dimensioned by GB/T 6170 / ISO 4032. The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.
M5 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 |
|---|---|---|---|---|---|
| M5 | 0.8 | 8.0 | 8.79 | 4.7 | ISO 4032 / GB/T 6170 |
Spanner & Drive for M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 061)
M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 061) have a width across flats of 8.0 mm — fit a 8.0 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.
Common Applications for M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 061)
M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 061) are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
Installation Tips for M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 061)
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- On flanged or serrated variants, do NOT add a separate flat washer — the flange already spreads the load and the washer can defeat the locking serrations.
- At M5 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
When to Step Up or Down from M5
When the joint preload approaches the proof load of M5 class 8.8, step up to M6 class 8.8 (or move to M5 class 10.9). When the joint is over-specified, M4 often saves weight and cost without losing the safety margin.

