For all-metal lock nuts, ISO 7042 defines the dimensions, tolerances and product grades. The sections below describe the scope of the document, the properties it deliberately leaves to companion standards, and the equivalent designations across standards bodies.
ISO 7042 — Scope
ISO 7042 specifies the dimensions and tolerances of all-metal lock nuts. Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
ISO 7042, alongside the related ISO 7042 / DIN 980 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by ISO 7042
| Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M5 | 0.8 | 8.0 | 6.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M6 | 1.0 | 10.0 | 7.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M8 | 1.25 | 13.0 | 9.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M10 | 1.5 | 16.0 | 11.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M12 | 1.75 | 18.0 | 13.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M14 | 2.0 | 21.0 | 15.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M16 | 2.0 | 24.0 | 17.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M18 | 2.5 | 27.0 | 19.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M20 | 2.5 | 30.0 | 21.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M24 | 3.0 | 36.0 | 24.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M30 | 3.5 | 46.0 | 30.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
| M36 | 4.0 | 55.0 | 36.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent All-Metal Lock Nuts page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify ISO 7042
Choose ISO 7042 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for all-metal lock nuts.