DIN 6798 A is the standard cited for external tooth lock washers. 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 6798 A — Scope
DIN 6798 A specifies the dimensional requirements for external tooth lock washers. 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 external tooth lock washers 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 6798 A
| Size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Thickness s (mm) | Type | Reference standard |
|---|---|---|---|---|---|
| M2 | 2.2 | 4.5 | 0.3 | External teeth | DIN 6798 A |
| M2.5 | 2.7 | 5.5 | 0.4 | External teeth | DIN 6798 A |
| M3 | 3.2 | 6 | 0.4 | External teeth | DIN 6798 A |
| M3.5 | 3.7 | 7 | 0.5 | External teeth | DIN 6798 A |
| M4 | 4.3 | 8 | 0.5 | External teeth | DIN 6798 A |
| M5 | 5.3 | 10 | 0.6 | External teeth | DIN 6798 A |
| M6 | 6.4 | 11 | 0.7 | External teeth | DIN 6798 A |
| M7 | 7.4 | 12.5 | 0.8 | External teeth | DIN 6798 A |
| M8 | 8.4 | 15 | 0.8 | External teeth | DIN 6798 A |
| M10 | 10.5 | 18 | 0.9 | External teeth | DIN 6798 A |
| M12 | 13 | 20.5 | 1 | External teeth | DIN 6798 A |
| M14 | 15 | 24 | 1 | External teeth | DIN 6798 A |
| M16 | 17 | 26 | 1.2 | External teeth | DIN 6798 A |
| M18 | 19 | 30 | 1.4 | External teeth | DIN 6798 A |
| M20 | 21 | 33 | 1.4 | External teeth | DIN 6798 A |
| M22 | 23 | 36 | 1.5 | External teeth | DIN 6798 A |
| M24 | 25 | 38 | 1.5 | External teeth | DIN 6798 A |
| M27 | 28 | 44 | 1.6 | External teeth | DIN 6798 A |
| M30 | 31 | 48 | 1.6 | External teeth | DIN 6798 A |
Companion Standards
DIN 6798 A controls only the geometry of external tooth lock washers. 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 6798 A
DIN 6798 A is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
