Standards
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ISO 14579 (Hexalobular Internal Drive), Not External 12-Point
ISO 14579 specifies the internal hexalobular socket head (a six-lobed star pattern recessed inside the bolt head, similar to Torx) used on cap screws. It is sometimes confused with external 12-point bolts because both involve twelve splines or contact points. They are different drive systems on different sides of the bolt head, requiring different drivers.
If the bolt has its drive pattern on the OUTSIDE of the head (twelve splines you grip from the outside with a 12-point socket wrench), it is an external 12-point bolt under MS21250, NAS1351, AS3216, or similar. If the bolt has its drive pattern on the INSIDE of the head (a six-lobed recessed socket you turn with a Torx-style internal driver), it is ISO 14579.
Side-by-Side Comparison
| Property | ISO 14579 (internal hexalobular) | External 12-point (MS21250 / NAS1351) |
|---|---|---|
| Drive location | Internal recessed socket inside head | External splines on outside of head |
| Drive pattern | 6-lobe star (12 contact points) | 12 external splines (every 30 degrees) |
| Driver tool | Hexalobular / Torx internal driver | 12-point socket wrench |
| Common standard | ISO 14579 | MS21250, NAS1351, AS3216, NAS6303-6320 |
| Typical market | European (DE, NL), industrial cap screws | US aerospace + motorsport |
TorqBolt Manufactures Both
TorqBolt produces ISO 14579 internal hexalobular cap screws AND external 12-point bolts (under MS21250, NAS1351, AS3216, NAS6303-6320) in alloy steel, A286, Inconel 718, and Ti-6Al-4V. Specify drive type clearly in your RFQ to avoid confusion at the manufacturing stage.
Why the confusion exists
German and Dutch engineering drawings frequently call out ISO 14579 for cap screws. English-language technical-spec searches for "ISO 14579" often surface alongside searches for "12-point bolt" because both involve twelve features on the bolt head. The features are on different sides of the head (internal recessed vs external protruding) and require different driver tools.
For external 12-point bolt clarification (the bolt vs the tool), see External vs Internal 12-Point. For the 12-point socket wrench tool itself, see Socket Wrench.
Naming and search confusion
The "12-point" label appears across three distinct fastener systems: external 12-point bolts (bolt with 12 splines OUTSIDE the head, driven by a 12-point socket wrench), internal hexalobular cap screws under ISO 14579 (cap screw with a 6-lobed star-shape socket recessed inside the head, driven by a Torx-style internal driver), and 12-point socket tools themselves (the wrench that drives the external bolt). All three involve "twelve" features and confuse search results. We make the bolts; we disambiguate so the right tool finds the right page.
Request a Quote
RFQ to info@torqbolt.com. Specify whether you need the ISO 14579 internal-drive or the external 12-point bolt.
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