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 Socket Sizes (Metric and Inch)
Common 12-point socket sizes used in aerospace, motorsport, and general automotive applications.
Metric Sizes
| Size | Common application |
|---|---|
| 8 mm | Small fasteners, motorsport accessory |
| 10 mm | General automotive |
| 12 mm | General automotive |
| 14 mm (thin-wall spark plug) | Modern engine spark plug removal |
| 17 mm, 19 mm, 21 mm | Wheel lug, suspension |
| 24 mm, 30 mm, 36 mm | Heavy-duty truck, diesel head bolts |
Inch Sizes
| Size | Common application |
|---|---|
| 1/4 inch | Small fasteners |
| 5/16 inch, 3/8 inch | Aerospace structural |
| 7/16 inch, 1/2 inch, 9/16 inch | Aerospace structural + automotive |
| 5/8 inch, 3/4 inch, 1 inch | Heavy structural + truck |
| 1-1/4 inch | Heavy industrial |
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.
Common 12-point socket sizes
Most 12-point sockets are sold in metric (8 mm to 32 mm in 1mm increments) and SAE inch (1/4 inch to 1-1/4 inch in standard automotive increments). Common sizes per drive system: 1/4-inch drive carries 8 mm to 14 mm sockets for trim and small-bracket fastening, 3/8-inch drive carries 10 mm to 22 mm for general automotive, and 1/2-inch drive carries 13 mm to 32 mm for engine and structural service. Spark-plug specific 14 mm and 16 mm thin-wall variants drop into 1/2-inch drive deep sockets.
For the bolt that the socket drives, see 12-point fastener catalog, flange variants, head bolts, cap screws, UNJ-3A dimensional reference. The 12-point socket clarification page covers the wider tool-vs-bolt question. The 6-point comparison: 12-point vs 6-point socket.
Standard size coverage by drive
Common 12-point socket sizing follows the bolt-head across-flats dimension. Metric: 8mm to 32mm in 1mm increments, with 14mm and 16mm thin-wall variants for spark plugs. Inch: 1/4 to 1-1/4 inch in standard automotive increments, occasionally with shallow and deep socket depth options for valve cover, exhaust manifold, and engine bay clearance. The 1/2-inch drive size handles head-bolt and main-cap-bolt service across most engine families; the 3/4-inch drive size handles structural and wheel-stud applications.
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