For spring lock washer (gb/t 93), DIN 12 is the governing document for the dimensions listed below. Mechanical and performance requirements for this part family are set by its own standards, not by the bolt and screw property-class documents.
DIN 12 — Scope
DIN 12 specifies the dimensional requirements for spring lock washer (gb/t 93) — gb/t 93 / din 127b (series 081). Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for spring lock washer (gb/t 93) — gb/t 93 / din 127b (series 081) are given as limits on the individual dimensions in the table rather than as a fastener product grade. Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by DIN 12
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Width b (mm) | Thickness t (mm) | Reference standard |
|---|---|---|---|---|---|
| M3 | 3.1 | 6.2 | 1.0 | 0.8 | GB/T 93 / DIN 127B |
| M4 | 4.1 | 7.6 | 1.2 | 1.0 | GB/T 93 / DIN 127B |
| M5 | 5.1 | 9.2 | 1.5 | 1.2 | GB/T 93 / DIN 127B |
| M6 | 6.1 | 11.8 | 2.0 | 1.6 | GB/T 93 / DIN 127B |
| M8 | 8.1 | 14.8 | 2.5 | 2.0 | GB/T 93 / DIN 127B |
| M10 | 10.2 | 18.1 | 3.0 | 2.5 | GB/T 93 / DIN 127B |
| M12 | 12.2 | 21.1 | 3.5 | 3.0 | GB/T 93 / DIN 127B |
| M14 | 14.2 | 24.1 | 4.0 | 3.5 | GB/T 93 / DIN 127B |
| M16 | 16.2 | 27.4 | 4.5 | 4.0 | GB/T 93 / DIN 127B |
| M18 | 18.2 | 29.4 | 5.0 | 4.5 | GB/T 93 / DIN 127B |
| M20 | 20.2 | 33.6 | 5.5 | 5.0 | GB/T 93 / DIN 127B |
| M24 | 24.5 | 40.1 | 6.5 | 6.0 | GB/T 93 / DIN 127B |
| M30 | 30.5 | 50.0 | 8.0 | 7.5 | GB/T 93 / DIN 127B |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Spring Lock Washer (GB/T 93) — GB/T 93 / DIN 127B (Series 081) page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 12
DIN 12 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.

