This page covers M12 Hex Nuts, Grade C to ISO 4034: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (ISO 4034 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M12 Dimensional Row (ISO 4034)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m (mm) | Product grade | Reference standard |
|---|---|---|---|---|---|---|
| M12 | 1.75 | 19.0 | 20.88 | 10.8 | Grade C | ISO 4034 / DIN 555 |
Spanner & Drive for M12 Hex Nuts, Grade C
M12 Hex Nuts, Grade C have a width across flats of 19.0 mm — fit a 19.0 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 M12 Hex Nuts, Grade C
M12 Hex Nuts, Grade C are commonly specified for medium-duty structural joints and motor / chassis mounting.
Installation Tips for M12 Hex Nuts, Grade C
- 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.
Mating Parts for M12
Pair M12 with the matching M12 bolt or screw, plus a M12 flat washer where required to distribute load on softer materials.