M33 Hex Nuts are manufactured to ISO 4032 / ISO 4033. This page lists the controlling dimensions for the M33 size together with the drive and the installation notes for this type.
M33 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 |
|---|---|---|---|---|---|---|
| M33 | 3.5 | 50.0 | 55.37 | 26.0 | 33.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M33 Hex Nuts
M33 Hex Nuts have a width across flats of 50.0 mm — fit a 50.0 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 M33 Hex Nuts
M33 Hex Nuts are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M33 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 M33 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 M33
Pair M33 with the matching M33 bolt or screw, plus a M33 flat washer where required to distribute load on softer materials.
