Dimensional and assembly data for M3 Nylon Insert Hex Lock Nut to GB/T 889 / ISO 7040. 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.
M3 Dimensional Row (GB/T 889 / ISO 7040)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Total height m (mm) | Reference standard |
|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 6.01 | 4.0 | ISO 7040 / DIN 985 |
Spanner & Drive for M3 Nylon Insert Hex Lock Nut — GB/T 889 / ISO 7040 (Series 078)
Drive geometry for M3 Nylon Insert Hex Lock Nut — GB/T 889 / ISO 7040 (Series 078) is given by the row above; match the tool to the listed values.
Common Applications for M3 Nylon Insert Hex Lock Nut — GB/T 889 / ISO 7040 (Series 078)
M3 Nylon Insert Hex Lock Nut — GB/T 889 / ISO 7040 (Series 078) are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
Installation Tips for M3 Nylon Insert Hex Lock Nut — GB/T 889 / ISO 7040 (Series 078)
- At M3 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
When to Step Up or Down from M3
When the joint preload approaches the proof load of M3 class 8.8, step up to M4 class 8.8 (or move to M3 class 10.9). When the joint is over-specified, M2 often saves weight and cost without losing the safety margin.