Overview - ISO 2982-2:2013 (Rolling bearings - Accessories)
ISO 2982-2:2013 specifies the geometric dimensions and key tolerances for locknuts and locking devices used with rolling bearings. This third edition (2013) defines dimensions for:
- locknuts with 4 and 8 slots,
- lockwashers with straight inner tabs (and informative annex for bent inner tabs),
- locking clip assemblies for 8‑slot locknuts,
and the runout tolerance of the locknut clamp face relative to the pitch diameter of the screw thread. The standard supports axial location of bearing inner rings on shafts and dismounting of withdrawal sleeves. It is part of the ISO 2982 series; see ISO 2982-1 for adapter sleeve and withdrawal sleeve dimensions.
Key topics and technical requirements
- Dimensional tables and nominal symbols: Figures and tables give nominal dimensions (diameters, slot widths and depths, clamp-face diameters, washer tabs, clip geometry) for a wide range of metric and trapezoidal thread sizes.
- Runout tolerance (t): The standard specifies permissible runout of the locknut clamp face with respect to the thread pitch diameter - a critical control for axial locating accuracy of bearings.
- Lockwashers and tabs: Requirements for lockwashers with straight inner tabs (mandatory) and bent inner tabs (informative annex) including tab widths, bore sizes and minimum numbers of outer tabs.
- Locking clip assemblies: Dimensions for the clip (C‑shaped) and associated bolt lengths and thread sizes used with 8‑slot locknuts.
- Thread tolerance classes and references: Thread tolerance guidance is provided (e.g., tolerance class 5H per ISO 965‑3 for metric threads and 7H per ISO 2901 for trapezoidal threads). Normative references include ISO 5593 (vocabulary) and ISO 15241 (symbols).
Applications and users
- Who uses it: Mechanical designers, bearing manufacturers, machine builders, maintenance engineers, procurement/specification teams, and quality/inspection personnel.
- Practical applications:
- Ensuring interchangeability and correct fit of locknuts and locking devices in bearing assemblies.
- Specifying components for axial positioning of bearing rings on shafts.
- Designing or selecting locking clip assemblies and lockwashers to prevent loosening in rotating equipment.
- Verifying runout/control requirements during inspection and assembly to maintain bearing performance and service life.
Related standards
- ISO 2982-1 - Dimensions for adapter sleeve assemblies and withdrawal sleeves (see for mating components).
- ISO 5593 - Rolling bearings - Vocabulary
- ISO 15241 - Rolling bearings - Symbols for physical quantities
- ISO 965-3 / ISO 2901 - Thread tolerance classes referenced in this part
ISO 2982-2:2013 is essential when specifying locknuts and locking devices for reliable bearing location, assembly interchangeability, and rotational accuracy in industrial machinery.