Specifications
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
12-Point vs 6-Point Socket
Engineering comparison of 12-point and 6-point sockets. Both fit external 12-point bolt heads, but they engage differently and have different torque capacities under high load.
| Property | 12-point socket | 6-point socket |
|---|---|---|
| Internal pattern | 12 splines (every 30 deg) | 6 flats (every 60 deg) |
| Engages 12-pt bolt | All 12 splines, full contact | Only 6 of 12 splines, half contact |
| Tool engagement angle | 30 deg minimum | 60 deg minimum |
| Torque capacity | Higher (full spline contact) | Lower (half spline contact) |
| Spline rounding risk | Low under high preload | Higher under high preload |
| Typical use | Aerospace + race engine builds | General automotive + industrial |
Recommendation
For external 12-point bolts torqued near or beyond their yield preload (typical of A286, MP35N, Inconel 718, or heat-treated 8740 in race-engine bolting), use a 12-point socket matched to the bolt head size. The 6-point socket fits but engages only half the splines and risks rounding the bolt head at the torque values typical of high-strength 12-point bolts.
Frequently asked questions
What is a 12-point bolt?
A 12-point bolt has 12 splines arranged every 30 degrees on the OUTSIDE of the bolt head, also called a bi-hex or double-hex bolt. The 12 external splines provide twice the wrench-engagement angles of a standard hex head, allowing higher applied torque before cam-off, which is why aerospace and motorsport applications adopt the geometry.
Are 12-point bolts the same as ISO 14579?
No. ISO 14579 specifies an INTERNAL hexalobular socket head (similar to Torx) recessed inside a cap screw. External 12-point bolts under MS21250 / NAS1351 / AS3216 use an EXTERNAL bi-hex head driven by a 12-point socket wrench. Both involve 12 features but on different sides of the bolt head and require different drivers.
Which alloys does TorqBolt manufacture 12-point bolts in?
TorqBolt produces 12-point bolts in A286 (UNS S66286), Inconel 718 (UNS N07718), Ti-6Al-4V Grade 5, MP35N (UNS R30035), Custom 465 H1025, AISI 8740 chromoly heat-treated, AISI 4340, 17-4 PH, H-11 tool steel, and L19 race-grade alloy steel. Choice depends on tensile target, service temperature, and corrosion environment.
Is TorqBolt AS9100D certified?
Yes. TorqBolt operates under AS9100D Rev D and ISO 9001:2015 quality management systems, audited annually by the registrar. NORSOK M-630 and NACE MR0175 / ISO 15156 qualifications cover offshore and sour-service applications. Mill test reports MTC 3.1 standard and MTC 3.2 critical-service witness are issued with every lot.
What lead time should I expect?
Stock alloys (A286, AISI 8740, AISI 4340, 17-4 PH, 316 stainless) ship in 4 to 6 weeks. Specialty alloys (Inconel 718, MP35N, Custom 465, Ti-6Al-4V, L19) ship in 8 to 12 weeks depending on raw-bar lead time at the alloy producer. Critical-service orders requiring third-party witness inspection (MTC 3.2) add 1 to 2 weeks for witness scheduling.
Trade-off in tool engagement
12-point sockets engage the bolt at every 30-degree rotation; 6-point sockets engage at every 60. The 12-point tool fits both 12-point external bolts AND 6-point hex bolts (since the 6 hex flats align with 6 of the 12 internal splines on the socket). The 6-point tool fits only 6-point hex bolts; on a 12-point external bolt the 6-point engages only 6 of the 12 splines and rounds them off under high torque. Use 12-point on aerospace and motorsport service for both reasons (better engagement quality + universal hex compatibility). Use 6-point only on hex bolts where lower-cost-tool budget rules.
For the bolts that drive these sockets see 12-point fastener catalog, flange variants, head bolts, cap screws, bi-hex synonyms. 12-point socket tool clarification, 12-point socket sizes chart, ISO 14579 internal hexalobular (different drive system entirely), external vs internal 12-point disambiguation.
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