Overview
ISO 8676:2022 specifies the characteristics of hexagon head screws with fine pitch thread (metric fine pitch threads M8×1 to M64×4) for product grades A and B. The standard covers screws in steel and stainless steel, giving dimensional requirements, allowable lengths, thread tolerances and references to material property classes, surface conditions, marking and labelling. It is the fourth edition (2022) and replaces ISO 8676:2011 with reorganized dimension tables and updated material and marking provisions.
Key topics and requirements
- Scope & sizes: Applies to hexagon head screws, fully threaded with fine pitch from M8×1 to M64×4, for product grades A (smaller diameters/lengths) and B (larger diameters/lengths or lengths beyond specified limits).
- Dimensions & lengths: Detailed dimensional tables (Clauses/Figures and Tables 1–5, Annex A) define head, thread and length ranges. Shortest standard length is determined from 2d and rounded; greatest standard length ≤ 10d or 200 mm, whichever is shorter. Longer lengths are by agreement.
- Threads & tolerances: Thread tolerance class 6g (reference: ISO 965-1). Thread and product tolerances governed by ISO 4759-1.
- Material & property classes: Steel property classes commonly referenced (e.g., 8.8, 10.9, and 12.9/12.9 added); stainless steel grades and property classes (A2, A4, D4, D6 and property class 80 added) can be selected from ISO 898-1 and ISO 3506-1 as required.
- Surface condition & coatings: Uncoated (clean/bright) or coated in accordance with ISO 4042 (electroplated) or ISO 10683 (zinc‑flake). Surface discontinuities and integrity per ISO 6157 series.
- Marking & labelling: Clause 6 defines product and package marking requirements (steel per ISO 898-1; stainless-steel marking also specified).
- Inspection & acceptance: Acceptance inspection follows ISO 3269.
Applications and users
ISO 8676:2022 is intended for:
- Fastener manufacturers and quality managers for production and inspection of hexagon head screws (fine pitch).
- Mechanical and design engineers specifying fasteners for machinery, automotive, construction and industrial equipment where fine pitch threads are required.
- Procurement specialists and purchasers who need standardized product grades, lengths and material classes in procurement documents.
- Test labs and QA/acceptance inspectors who verify dimensions, material class and surface treatments against ISO requirements.
Practical benefits include consistent interchangeability, clear dimensional limits, and harmonized references for material and coating selection.
Related standards
Keywords: ISO 8676:2022, hexagon head screws, fine pitch thread, metric fine pitch, product grades A and B, fastener dimensions, thread tolerances, property class, stainless steel grades, marking and labelling.
