M16 Hex Nuts are manufactured to ISO 4032 / ISO 4033 with a coarse thread pitch of 2 mm. This page lists the controlling dimensions for the M16 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M16 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 |
|---|---|---|---|---|---|---|
| M16 | 2.0 | 24.0 | 26.75 | 13.0 | 16.0 | ISO 4032 (Style1) / ISO 4033 (Style2) |
Spanner & Drive for M16 Hex Nuts
M16 Hex Nuts have a width across flats of 24.0 mm — fit a 24.0 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 M16 Hex Nuts
M16 Hex Nuts are commonly specified for medium-duty structural joints and motor / chassis mounting.
Mating Parts for M16
Pair M16 with the matching M16 bolt or screw, plus a M16 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M16
When the joint preload approaches the proof load of M16 class 8.8, step up to M20 class 8.8 (or move to M16 class 10.9). When the joint is over-specified, M12 often saves weight and cost without losing the safety margin.