EN ISO 7380-2:2023 specifies hexagon socket button head screws with collar (button head screws) having reduced loadability due to head geometry. The standard covers steel fasteners with metric coarse pitch threads M3 to M16, product grade A, and defines dimensional, marking and testing requirements. It is the CEN-endorsed European adoption of ISO 7380-2:2022 and replaces the 2011 edition.
Key topics and technical requirements
- Scope and sizes: Thread sizes M3–M16, coarse pitch; product grade A.
- Reduced loadability: Head design (head dimensions and socket penetration) limits ultimate tensile load. The loadability in the head is assumed to be 80% of that in the thread (see Table 4). This limitation is indicated by a specific marking: the property class is preceded by a zero on the screw.
- Dimensions and tolerances: Detailed dimensions, symbols and tolerances are provided in Figures 1–3 and Tables 1–2 (including socket geometry, head diameter, bearing face datum and wall thickness w). The standard permits an alternative broached socket form and specifies maximum socket depth t and related dimensions.
- Thread and length rules: Reference thread length and shank/grip lengths are defined; for tensile testing of screws with reduced loadability the reference thread length for partially threaded M16 has been increased to b ≥ 3d to enable testing per ISO 3506‑1.
- Marking and labelling: Clause 6 requires marking on the product and labelling on packaging to show property class and identification of reduced loadability.
- Normative references: Cross-references include ISO 225, ISO 888, ISO 4753, ISO 898‑1, ISO 965‑1, ISO 4759‑1 and other core fastener standards relevant to threads, lengths, coatings and mechanical properties.
Practical applications and users
Who uses EN ISO 7380-2:2023:
- Fastener manufacturers defining production and QA criteria for hexagon socket button head screws with collar.
- Design engineers selecting low-profile button head screws where head geometry reduces bearing capacity (e.g., electronics housings, light‑duty assemblies, decorative or flush applications).
- Procurement, inspection and quality teams ensuring correct marking, dimensional conformity and acceptance testing.
- Standards and compliance specialists coordinating product documentation and labelling for European markets.
Why it matters:
- Ensures consistent dimensions, safe use limits and traceable marking for screws with intentionally reduced head loadability.
- Enables correct tensile testing and conformity assessment (references to ISO 3506‑1, ISO 3269).
Related standards
Keywords: EN ISO 7380-2:2023, ISO 7380-2, button head screws, hexagon socket, collar, reduced loadability, M3–M16, product grade A, fasteners standard.