This page covers M3 Hex Slotted Castle Nut (Type 1) to GB/T 6180 / ISO 7036: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (GB/T 6180 / ISO 7036 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M3 Dimensional Row (GB/T 6180 / ISO 7036)
| 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 Hex Slotted Castle Nut (Type 1) — GB/T 6180 / ISO 7036 (Series 049)
Drive geometry for M3 Hex Slotted Castle Nut (Type 1) — GB/T 6180 / ISO 7036 (Series 049) is given by the row above; match the tool to the listed values.
Common Applications for M3 Hex Slotted Castle Nut (Type 1) — GB/T 6180 / ISO 7036 (Series 049)
M3 Hex Slotted Castle Nut (Type 1) — GB/T 6180 / ISO 7036 (Series 049) are commonly specified for paired with the same-size screws on PCB hardware, light enclosures and small-scale assemblies.
Installation Tips for M3 Hex Slotted Castle Nut (Type 1) — GB/T 6180 / ISO 7036 (Series 049)
- 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.
Mating Parts for M3
Pair M3 with the matching M3 bolt or screw, plus a M3 flat washer where required to distribute load on softer materials.

