M5 is one of the standard coarse-thread sizes for hex nut under GB/T 6170 / ISO 4032. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.
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 059)
M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 059) 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 059)
M5 Hex Nut — GB/T 6170 / ISO 4032 (Series 059) 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 059)
- 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.
Mating Parts for M5
Pair M5 with the matching M5 bolt or screw, plus a M5 flat washer where required to distribute load on softer materials.