Dimensional and assembly data for M12 Swing Bolt to GB/T 77 / ISO 4026. 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.
M12 Dimensional Row (GB/T 77 / ISO 4026)
| Thread size | Pitch (mm) | Ring outer dia D (mm) | Ring wire dia (mm) | Total length L (mm) | SWL (kg, axial) | Reference standard |
|---|---|---|---|---|---|---|
| M12 | 1.75 | 30 | 12 | 54 | 340 | DIN 580 / GB/T 825 |
Spanner & Drive for M12 Swing Bolt — GB/T 77 / ISO 4026 (Series 020)
Drive geometry for M12 Swing Bolt — GB/T 77 / ISO 4026 (Series 020) is given by the row above; match the tool to the listed values.
Hole Sizes for M12
| Coarse-thread pitch (ISO 724) | 1.75 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 13.5 mm |
| Tapping drill, coarse thread | 10.2 mm |
Tightening Torque for M12
| Class 8.8 (dry, ~µ 0.125) | ≈ 85 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 120 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 145 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M12
| Tensile stress area As (ISO 898-1) | 84.3 mm² |
|---|---|
| Proof load, class 8.8 | 49 kN |
| Proof load, class 10.9 | 70 kN |
| Proof load, class 12.9 | 82 kN |
| Min. ultimate tensile, class 8.8 | 67 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M12 Swing Bolt — GB/T 77 / ISO 4026 (Series 020) Weight
A steel M12 swing bolt at the listed 54 mm length weighs approximately 48 g each — about 48 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³). Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Common Applications for M12 Swing Bolt — GB/T 77 / ISO 4026 (Series 020)
M12 Swing Bolt — GB/T 77 / ISO 4026 (Series 020) are commonly specified for medium-duty structural connections, automotive sub-frames and equipment chassis.
Mating Parts for M12
For M12, pair with a M12 hex nut (ISO 4032 / DIN 934) and, where used, a M12 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M12
When the joint preload approaches the proof load of M12 class 8.8, step up to M16 class 8.8 (or move to M12 class 10.9). When the joint is over-specified, M10 often saves weight and cost without losing the safety margin.