A square nut — gb/t 39 / iso 4034 (series 075 in M20: this guide pulls the row from the standard, adds the assembly numbers an engineer actually uses, and links you straight to a quote.
M20 Dimensional Row (GB/T 39 / ISO 4034)
| Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard |
|---|---|---|---|---|
| M20 | 2.5 | 30.0 | 12.0 | GB/T 39 / DIN 562 |
Spanner & Drive for M20 Square Nut — GB/T 39 / ISO 4034 (Series 075)
Drive geometry for M20 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 M20 Square Nut — GB/T 39 / ISO 4034 (Series 075)
M20 Square Nut — GB/T 39 / ISO 4034 (Series 075) are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M20 Square Nut — GB/T 39 / ISO 4034 (Series 075)
- At M20 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 M20
Pair M20 with the matching M20 bolt or screw, plus a M20 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M20
When the joint preload approaches the proof load of M20 class 8.8, step up to M24 class 8.8 (or move to M20 class 10.9). When the joint is over-specified, M16 often saves weight and cost without losing the safety margin.