EN ISO 14581:2023 PDF

Overview

EN ISO 14581:2023 (ISO 14581:2022) defines requirements for hexalobular socket countersunk flat head screws (common head style) with reduced loadability. It covers steel and stainless‑steel fasteners with metric coarse pitch threads M2 to M10, product grade A. The standard specifies head dimensions, gauging, marking, labelling and performance limits that arise from the reduced head geometry and hexalobular socket penetration.

Key topics and requirements

• Scope and materials: Applies to steel and stainless‑steel screws, M2–M10, product grade A. Stainless‑steel grades can be selected per ISO 3506‑1 when other specifications are requested.
• Reduced loadability: The head design (countersunk head dimensions combined with socket penetration) reduces ultimate tensile load in the head. Loadability in the head is assumed to be 80% of that in the thread for all sizes/property classes. Reduced loadability is indicated by a property class preceded by a zero on the marking.
• Dimensions & gauging: Detailed head dimensions, minimum head height, radius and underhead reinforcement (where applicable) are specified. Dimensional options may reference ISO 888 or ISO 4753.
• Marking and labelling: Requirements for product marking (including property class notation for reduced loadability) and package labelling are included.
• Design and inspection: Figures and tables define head configuration, gauging criteria and minimum tensile loads (with calculations for small sizes M2 and M2.5 where needed).
• Interchangeability: These reduced‑load countersunk flat head screws are not interchangeable with the high‑head full‑load hexalobular countersunk screws specified in ISO 14582 due to different head heights.
• Assembly guidance: Emphasises correct alignment of the countersunk head with the countersink bearing surface to ensure performance.

Applications and users

• Typical applications: flush, countersunk fastenings in electronics, enclosures, automotive trim, precision assemblies and any design requiring a flush head where reduced head material is acceptable.
• Who uses it: mechanical designers, fastener manufacturers, procurement teams, quality/inspection engineers and assembly technicians specifying or verifying hexalobular socket countersunk flat head screws with reduced loadability.
• Practical value: ensures consistent dimensions, predictable reduced tensile performance, and clear marking so designers and assemblers can select appropriate screws and avoid mismating with full‑load variants.

Related standards

• ISO 14582 - hexalobular countersunk head screws (high head, full loadability)
• ISO 3506‑1 - stainless‑steel fastener grades
• ISO 7721 - countersunk head configuration and gauging
• ISO 888 / ISO 4753 - length and end‑of‑part dimensional options
• ISO 898‑1, ISO 10664, ISO 8991 - fastener mechanical/design referencing

Keywords: EN ISO 14581:2023, ISO 14581:2022, hexalobular socket countersunk flat head screws, reduced loadability, fasteners, M2–M10, product grade A.