For bearing lock washers (mb series), DIN 5406 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 5406 — Scope
DIN 5406 specifies the dimensional requirements for bearing lock washers (mb series). 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 bearing lock washers (mb series) 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 5406
| Designation | Shaft thread | Bore d1 (mm) | Outer diameter d2 (mm) | Thickness s (mm) | Number of outer tabs | Mating lock nut | Reference standard |
|---|---|---|---|---|---|---|---|
| MB0 | M10x0.75 | 10 | 21 | 1.0 | 11 | KM0 | DIN 5406 |
| MB1 | M12x1 | 12 | 25 | 1.0 | 11 | KM1 | DIN 5406 |
| MB2 | M15x1 | 15 | 28 | 1.0 | 11 | KM2 | DIN 5406 |
| MB3 | M17x1 | 17 | 32 | 1.0 | 11 | KM3 | DIN 5406 |
| MB4 | M20x1 | 20 | 36 | 1.0 | 11 | KM4 | DIN 5406 |
| MB5 | M25x1.5 | 25 | 42 | 1.25 | 13 | KM5 | DIN 5406 |
| MB6 | M30x1.5 | 30 | 49 | 1.25 | 13 | KM6 | DIN 5406 |
| MB7 | M35x1.5 | 35 | 57 | 1.25 | 13 | KM7 | DIN 5406 |
| MB8 | M40x1.5 | 40 | 62 | 1.25 | 13 | KM8 | DIN 5406 |
| MB9 | M45x1.5 | 45 | 69 | 1.25 | 13 | KM9 | DIN 5406 |
| MB10 | M50x1.5 | 50 | 74 | 1.25 | 13 | KM10 | DIN 5406 |
| MB11 | M55x2 | 55 | 81 | 1.5 | 13 | KM11 | DIN 5406 |
| MB12 | M60x2 | 60 | 86 | 1.5 | 13 | KM12 | DIN 5406 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Bearing Lock Washers (MB Series) page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 5406
DIN 5406 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
