M12 Square Nut are manufactured to GB/T 39 / ISO 4034 with a coarse thread pitch of 1.75 mm. This page lists the controlling dimensions for the M12 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M12 Dimensional Row (GB/T 39 / ISO 4034)
| Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard |
|---|---|---|---|---|
| M12 | 1.75 | 19.0 | 7.0 | GB/T 39 / DIN 562 |
Spanner & Drive for M12 Square Nut — GB/T 39 / ISO 4034 (Series 075)
Drive geometry for M12 Square Nut — GB/T 39 / ISO 4034 (Series 075) is given by the row above; match the tool to the listed values.
Common Applications for M12 Square Nut — GB/T 39 / ISO 4034 (Series 075)
M12 Square Nut — GB/T 39 / ISO 4034 (Series 075) are commonly specified for medium-duty structural joints and motor / chassis mounting.
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.
When to Step Up or Down from M12
When the joint preload approaches the proof load of M12 class 8.8, step up to M16 class 8.8 (or move to M12 class 10.9). When the joint is over-specified, M10 often saves weight and cost without losing the safety margin.