Dimensional and assembly data for M8 Square Nut, Metric to GB/T 39 / ISO 4034. Includes head size and width across flats, clearance-hole and tapping-drill diameters, tightening torque per property class, and the sizes to step up or down to when the joint requires it.
M8 Dimensional Row (GB/T 39 / ISO 4034)
| Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard |
|---|---|---|---|---|
| M8 | 1.25 | 13.0 | 4.8 | GB/T 39 / DIN 562 |
Spanner & Drive for M8 Square Nut, Metric — GB/T 39 / ISO 4034 (Series 076)
Drive geometry for M8 Square Nut, Metric — GB/T 39 / ISO 4034 (Series 076) is given by the row above; match the tool to the listed values.
Common Applications for M8 Square Nut, Metric — GB/T 39 / ISO 4034 (Series 076)
M8 Square Nut, Metric — GB/T 39 / ISO 4034 (Series 076) are commonly specified for general-purpose joints in machinery, fixturing and equipment frames.
Mating Parts for M8
Pair M8 with the matching M8 bolt or screw, plus a M8 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M8
When the joint preload approaches the proof load of M8 class 8.8, step up to M10 class 8.8 (or move to M8 class 10.9). When the joint is over-specified, M6 often saves weight and cost without losing the safety margin.