M5 Hex Nuts (ISO 4032 / ISO 4033) are specified by thread size, length and head dimensions. The M5 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M5 Dimensional Row (ISO 4032 / ISO 4033)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m style 1 (mm) | Nut height m style 2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M5 | 0.8 | 8.0 | 8.79 | 4.0 | 5.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M5 Hex Nuts
M5 Hex Nuts 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 Nuts
M5 Hex Nuts are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
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.
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.