Overview
ISO 10664:2014 - Hexalobular internal driving feature for bolts and screws - defines the shape, basic dimensions and gauging method for hexalobular (six‑lobe) internal driving features used in bolts and screws. The standard provides the geometric details and GO/NO‑GO gauging criteria required for inspection, including tables of limiting sizes for gauges and fallaway allowances. It is explicitly an inspection standard, not a manufacturing specification.
Key topics
- Basic dimensions: Nominal socket sizes and dimensional parameters (see Tables 1 and 2) that describe the hexalobular feature geometry and counterbore constraints.
- Gauging principle: Requirements for GO and NO‑GO gauges to verify entry and fallaway to the specified penetration depth (t) as referenced in the relevant product standards.
- GO gauge: Dimensions and tolerances for the GO gauge that must enter freely to the required depth (see Table 3).
- NO‑GO gauges: Two NO‑GO checks - one for the A and R contour fallaway (Table 4) and a cylindrical NO‑GO for dimension B (Table 5). NO‑GO gauges must not enter beyond the fallaway allowance.
- Measurement references: Gauging is performed relative to the head top surface; guidance on dial gauge zeroing is included.
- Designation and drawing aid: How to designate the socket (e.g., “Hexalobular internal driving feature ISO 10664 – 20”) and Annex A which provides contour correlations useful for CAD representation.
Applications
- Quality control and inspection: Primary use is by inspection labs and quality departments to verify conformity of hexalobular sockets in fasteners.
- Design documentation: Engineers and CAD designers can use the contour guidance (Annex A) and basic dimensions when specifying internal drive features in product drawings.
- Procurement and standards compliance: Purchasing and standards teams use ISO 10664 references to ensure supplied fasteners meet inspection criteria.
Note: Because ISO 10664:2014 is not a manufacturing standard, it should be used alongside production specifications and relevant product standards that define penetration depth and material/functional requirements.
Related standards
- Developed by ISO/TC 2 (Fasteners), SC 11. ISO 10664:2014 refers to "relevant product standards" for penetration depth (t) - consult the applicable fastener product standard for complete functional requirements.
Keywords: ISO 10664:2014, hexalobular internal driving feature, hexalobular socket, GO gauge, NO‑GO gauge, gauging method, inspection, fallaway allowance, bolts and screws.
