Overview
ISO 15072:2012 specifies the characteristics of hexagon bolts with flange with metric fine pitch thread - small series - product grade A. It covers nominal thread diameters from M8 up to and including M16 and property classes 8.8, 9.8, 10.9, 12.9 (12.9/12.9) and A2‑70. The standard defines dimensions, tolerances, mechanical properties, finishes and acceptance criteria for these flange hexagon bolts with fine pitch threads.
Key topics and requirements
- Dimensions and geometry: Detailed head, flange and shank dimensions (see Figures 1–4 and Table 1 in the standard) for full shank, reduced shank (type R) and underhead configurations. Wrenching heights, corner radii and flange thicknesses are specified.
- Thread and tolerances: Metric fine pitch threads to ISO general thread plans and tolerance class 6g; reference to ISO 261 and ISO 965-2 for thread form and limits.
- Mechanical properties and property classes: Applicable property classes 8.8, 9.8, 10.9, 12.9/12.9 for steel and A2‑70 for stainless steel, with mechanical requirements referenced to ISO 898-1 and ISO 3506-1.
- Surface finish and coatings: Electroplated coatings per ISO 4042, zinc‑flake coatings per ISO 10683, and passivation for stainless steels per ISO 16048. Additional finishes agreed between supplier and purchaser.
- Product grade and tolerances: Product grade A tolerances per ISO 4759-1; general fastener requirements per ISO 8992.
- Acceptance and gauging: Acceptance inspection according to ISO 3269. Annex A provides a normative method for gauging hexagon flange heads using ring gauges (A, B, C) to confirm head height, corner fill and flange thickness.
Applications
ISO 15072:2012 is used where compact hexagon flange bolts with fine pitch threads are required:
- Automotive and machinery assemblies where fine pitch threads provide improved clamping control.
- Precision engineering, instrumentation and aerospace subassemblies requiring small series fasteners.
- Replacement parts and procurement specifications where consistent interchangeability and mechanical performance are essential.
Who should use this standard
- Fastener manufacturers and quality control engineers for design, production and inspection.
- Procurement/specification authors and OEM engineers specifying fasteners for assemblies.
- Test laboratories and inspectors performing acceptance inspection and gauging.
Related standards
Relevant references include ISO 225, ISO 261, ISO 898-1, ISO 965-2, ISO 3506-1, ISO 4759-1, ISO 4042, ISO 10683, ISO 16048, ISO 3269 and other ISO fastener standards (see ISO 15072 bibliography).
Example designation:
Hexagon bolt with flange ISO 15072 - M12 × 1.25 × 80 - 8.8 (product grade A, fine pitch)