DIN 985 is the governing dimensional standard for nyloc lock nuts. 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.
DIN 985 — Scope
DIN 985 is "Prevailing torque type hexagon thin nuts with non-metallic insert".
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
DIN 985 does not divide nyloc lock nuts into product grades. Tolerances are given as limits on the individual dimensions in the table.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by DIN 985
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Total height m (mm) | Metal height (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 6.01 | 4.0 | 2.4 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M4 | 0.7 | 7.0 | 7.66 | 5.0 | 3.2 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M5 | 0.8 | 8.0 | 8.79 | 5.0 | 3.7 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M6 | 1.0 | 10.0 | 11.05 | 6.0 | 4.7 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M8 | 1.25 | 13.0 | 14.38 | 8.0 | 6.14 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M10 | 1.5 | 16.0 | 17.77 | 10.0 | 8.04 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M12 | 1.75 | 18.0 | 20.03 | 12.0 | 9.64 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M14 | 2.0 | 21.0 | 23.36 | 14.0 | 11.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M16 | 2.0 | 24.0 | 26.75 | 16.0 | 13.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M20 | 2.5 | 30.0 | 32.95 | 20.0 | 16.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M24 | 3.0 | 36.0 | 39.55 | 22.0 | 19.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M30 | 3.5 | 46.0 | 50.85 | 25.0 | 24.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
| M36 | 4.0 | 55.0 | 60.79 | 29.0 | 29.0 | DIN 985 / ISO 7040 | With nylon insert, single use |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Nyloc Lock Nuts page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 985
DIN 985 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
Custom manufacturing · Made to drawing
Need a nut to this standard in a non-standard size?
Parts built to DIN 985 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
