M4 Hex Nuts is the m4-thread variant of Hex Nuts manufactured to ISO 4032 / ISO 4033. This page focuses on the data engineers reach for at the bench: dimensional values for the M4 size, the spanner/drive that fits, and the assembly data you need to install it.
M4 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 |
|---|---|---|---|---|---|---|
| M4 | 0.7 | 7.0 | 7.66 | 3.2 | - | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M4 Hex Nuts
M4 Hex Nuts have a width across flats of 7.0 mm — fit a 7.0 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 M4 Hex Nuts
M4 Hex Nuts are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
Installation Tips for M4 Hex Nuts
- 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 M4 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 M4
Pair M4 with the matching M4 bolt or screw, plus a M4 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M4
When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 often saves weight and cost without losing the safety margin.