The M22 size of Hex Nuts, Grade C is dimensioned by ISO 4034. The table below gives the dimensional row from the standard, followed by the drive and the installation notes for this type.
M22 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 |
|---|---|---|---|---|---|---|
| M22 | 2.5 | 32.0 | 35.72 | 19.4 | Grade C | ISO 4034 / DIN 555 |
Spanner & Drive for M22 Hex Nuts, Grade C
M22 Hex Nuts, Grade C have a width across flats of 32.0 mm — fit a 32.0 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 M22 Hex Nuts, Grade C
M22 Hex Nuts, Grade C are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M22 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 M22 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 M22
Pair M22 with the matching M22 bolt or screw, plus a M22 flat washer where required to distribute load on softer materials.

