For jam nuts (thin hex, inch), ASME B18.2.2 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.
ASME B18.2.2 — Scope
ASME B18.2.2 specifies the dimensions and tolerances of jam nuts (thin hex, inch). 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
ASME B18.2.2, alongside the related ASME B18.2.2 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 ASME B18.2.2
| Thread size | Across flats s (mm) | Across corners e (mm) | Nut height m (mm) | Across flats (in) | Nut height (in) | Reference standard |
|---|
Companion Standards
ASME B18.2.2 controls only the geometry of jam nuts (thin hex, inch). The mechanical strength is set by ISO 898-1 (bolts and screws) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards (e.g. ISO 4042 for electroplating). For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
When to Specify ASME B18.2.2
ASME B18.2.2 is the inch-based reference; for metric programs choose the ISO equivalent instead.
