M30 Hex Nuts, Grade C are manufactured to ISO 4034 with a coarse thread pitch of 3.5 mm. This page lists the controlling dimensions for the M30 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M30 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 |
|---|---|---|---|---|---|---|
| M30 | 3.5 | 46.0 | 50.85 | 25.6 | Grade C | ISO 4034 / DIN 555 |
Spanner & Drive for M30 Hex Nuts, Grade C
M30 Hex Nuts, Grade C have a width across flats of 46.0 mm — fit a 46.0 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 M30 Hex Nuts, Grade C
M30 Hex Nuts, Grade C are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M30 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.
- At M30 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M30
Pair M30 with the matching M30 bolt or screw, plus a M30 flat washer where required to distribute load on softer materials.