Overview
EN ISO 2009:2011 (ISO 2009:2011) specifies the characteristics of slotted countersunk flat head screws - product grade A with metric external threads from M1.6 to M10 inclusive. Published by ISO and adopted by CEN, this international standard defines dimensional, material and inspection requirements for general-purpose slotted countersunk screws used across mechanical assemblies.
Key topics and technical requirements
- Scope and sizes: Covers nominal thread sizes M1.6 to M10, with associated pitch and preferred lengths defined in the standard.
- Dimensions & head form: Head, slot and shank geometry are given (symbols per ISO 225), including references for head configuration and gauging.
- Materials & property classes:
- Carbon/alloy steels with property classes 4.8, 5.8
- Stainless steels such as A2-50, A2-70
- Non‑ferrous metals also allowed with applicable mechanical property requirements
- Tolerances & thread quality:
- General purpose metric thread references (ISO 261, ISO 965-2)
- Tolerance class 6g for external threads
- Product grade A tolerances per ISO 4759-1
- Mechanical properties & testing:
- Surface, coatings and finish:
- Inspection & acceptance: Acceptance inspection procedures referenced to ISO 3269.
- Designation: Example format - Countersunk flat head screw ISO 2009 - M5 × 20 - 4.8
Practical applications
- Used by manufacturers, fastener suppliers and purchasing engineers specifying slotted countersunk flat head screws for:
- Consumer products and appliance assembly
- Sheet-metal work and fastening where a flush countersunk head is required
- Prototype and repair work where standard metric slotted screws are preferred
- Useful in procurement documents, engineering drawings and quality control plans to ensure interchangeability and consistent performance.
Who should use this standard
- Fastener manufacturers and quality engineers
- Mechanical designers and product engineers
- Procurement professionals and standards compliance officers
- Test laboratories and inspectors performing acceptance checks
Related standards
This concise reference helps ensure correct specification, interchangeability and quality control when selecting slotted countersunk flat head screws under ISO 2009:2011.
