DIN 12 is the standard cited for spring lock washer. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
DIN 12 — Scope
DIN 12 specifies the dimensional requirements for spring lock washer — gb/t 93 / din 127b (series 082). 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 / din 127b (series 082) 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 |
Companion Standards
DIN 12 controls only the geometry of spring lock washer — gb/t 93 / din 127b (series 082). Surface finish is governed by separate finish standards (for example ISO 4042 for electroplating), and corrosion testing by ISO 9227 (neutral salt spray). Mechanical performance is set by the standards specific to this part family, not by ISO 898-1 or ISO 898-2, which apply to bolts, screws and nuts.
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.
