Dimensional and assembly data for M3 Thin Hex Castle Nut to GB/T 6181 / ISO 4035. 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 6181 / ISO 4035)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Total height m (mm) | Slot width (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 6.01 | 4.0 | 1.2 | ISO 7036 / GB/T 6180 |
Spanner & Drive for M3 Thin Hex Castle Nut — GB/T 6181 / ISO 4035 (Series 053)
Drive geometry for M3 Thin Hex Castle Nut — GB/T 6181 / ISO 4035 (Series 053) is given by the row above; match the tool to the listed values.
Common Applications for M3 Thin Hex Castle Nut — GB/T 6181 / ISO 4035 (Series 053)
M3 Thin Hex Castle Nut — GB/T 6181 / ISO 4035 (Series 053) are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
Installation Tips for M3 Thin Hex Castle Nut — GB/T 6181 / ISO 4035 (Series 053)
- 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.