GB is the governing dimensional standard for swing bolt. This page sets out the scope of the standard, reproduces the full size table it specifies, and lists the DIN/ISO/ASME cross-references commonly cited in datasheets and drawings.
GB — Scope
GB specifies the dimensions and tolerances of swing bolt — gb/t 77 / iso 4026 (series 020). Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
GB, alongside the related GB/T 77 / ISO 4026 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by GB
| Thread size | Pitch (mm) | Ring outer dia D (mm) | Ring wire dia (mm) | Total length L (mm) | SWL (kg, axial) | Reference standard |
|---|---|---|---|---|---|---|
| M8 | 1.25 | 20 | 8 | 36 | 140 | DIN 580 / GB/T 825 |
| M10 | 1.5 | 25 | 10 | 45 | 230 | DIN 580 / GB/T 825 |
| M12 | 1.75 | 30 | 12 | 54 | 340 | DIN 580 / GB/T 825 |
| M16 | 2.0 | 35 | 14 | 63 | 700 | DIN 580 / GB/T 825 |
| M20 | 2.5 | 40 | 16 | 72 | 1200 | DIN 580 / GB/T 825 |
| M24 | 3.0 | 50 | 20 | 90 | 1800 | DIN 580 / GB/T 825 |
| M30 | 3.5 | 60 | 25 | 108 | 3200 | DIN 580 / GB/T 825 |
| M36 | 4.0 | 72 | 30 | 126 | 5000 | DIN 580 / GB/T 825 |
Companion Standards
GB controls only the geometry of swing bolt — gb/t 77 / iso 4026 (series 020). The mechanical strength is set by ISO 898-1 (bolts and screws) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards (e.g. ISO 4042 for electroplating). For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
When to Specify GB
Choose GB for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for swing bolt — gb/t 77 / iso 4026 (series 020).