Overview
EN ISO 14579:2011 (ISO 14579:2011) specifies the characteristics of hexalobular socket head cap screws - cylindrical-head screws with an internal six‑lobe driving feature - for metric thread sizes M2 to M20, product grade A. The European adoption (EN ISO 14579) aligns with the international text and updates the 2001 edition. The standard covers dimensional requirements, designation, material and mechanical property references, tolerances and acceptance criteria needed for consistent manufacturing, procurement and inspection of these fasteners.
Key Topics
- Scope and designation
- Applies to hexalobular socket head cap screws with threads M2 … M20, product grade A.
- Example designation: Hexalobular socket head cap screw ISO 14579 - M5 × 20 - 8.8.
- Dimensions and geometry
- Head, socket and thread dimensions are specified (see figure and Table 1 in the standard) including maximum/minimum values and preferred lengths.
- Hexalobular socket acceptance and gauges referenced to ISO 10664.
- Material and mechanical requirements
- References to mechanical property standards for different materials:
- Tolerance class: 5g6g for property class 12.9; 6g for other classes (as specified).
- Surface finish, coatings and surface integrity
- Inspection and tolerances
Applications and Users
- Intended for anyone specifying, producing, procuring or inspecting hexalobular socket head cap screws:
- Mechanical designers and engineers
- Fastener manufacturers and quality-control teams
- Procurement specialists and suppliers of metric fasteners
- Test laboratories and conformity assessors
- Hexalobular socket head cap screws are commonly used where compact heads and reliable internal drive engagement are required in mechanical assemblies, automotive components, industrial machinery and precision equipment.
Related Standards (key references)
Keywords: hexalobular socket head cap screws, ISO 14579, EN ISO 14579:2011, metric screws M2–M20, socket head cap screw dimensions, fastener standards.