For thin nylon insert lock nuts (din 985), DIN 985 fixes the geometry and the tolerances. The sections below describe the scope of the document, the properties it deliberately leaves to companion standards, and the equivalent designations across standards bodies.
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 thin nylon insert lock nuts (din 985) 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
| Thread size | Pitch (mm) | Width across flats s (mm) | Total height m (mm) | Max service temperature (u00b0C) | Re-use | Property class | Reference standard |
|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 8.0 | 5.0 | 120 | 5 cycles typical | 8 | DIN 985 |
| M6 | 1.0 | 10.0 | 6.0 | 120 | 5 cycles typical | 8 | DIN 985 |
| M8 | 1.25 | 13.0 | 8.0 | 120 | 5 cycles typical | 8 | DIN 985 |
| M10 | 1.5 | 17.0 | 10.0 | 120 | 5 cycles typical | 8 | DIN 985 |
| M12 | 1.75 | 19.0 | 12.0 | 120 | 5 cycles typical | 8 | DIN 985 |
| M16 | 2.0 | 24.0 | 16.0 | 120 | 5 cycles typical | 8 | DIN 985 |
Companion Standards
DIN 985 controls only the geometry of thin nylon insert lock nuts (din 985). The mechanical strength is set by ISO 898-1 (bolts, screws and studs) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards such as ISO 4042 for electroplating. For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
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.
