Products · Bolts
12 point bolts
Bi-hex and 12 point bolts and screws for turbines, large machines and other critical joints, made to IFI 115 or your drawing in Inconel 718 and high strength alloy steels.
IFI 115
Or your own drawing
1 to 500
Single prototypes to batches of several hundred
UK, EU, US
Mill origin of every bar we use
3.1 / 3.2
EN 10204 certificates with full traceability
About 12 point bolts
Compact heads for high loads
12 point bolts, also called bi-hex or double hexagon bolts, have a head with twelve points that a 12 point socket grips on every flat. The smaller head carries high torque in a tight space, so 12 point bolts are used where clearance is limited and preload is high. HAGUE FASTENERS makes them in the UK, from weight balanced turbine screws to large machine pole screws.
Many of our 12 point screws are made in Inconel 718 or highly specified carbon alloy steels, with ultrasonic testing and magnetic particle inspection backing decades of experience in production methods.
Where 12 point bolts are used
- Gas and steam turbines
- Large electrical machines and generators
- Compact, high preload flanged joints
- High temperature casings
- High strength machinery joints
Options
Typical specifications
Typical options. We make to the standard or drawing you specify.
| Option | What we make |
|---|---|
| Head | 12 point, flanged 12 point, weight balanced or special |
| Thread | Metric coarse and fine, UNC, UNF, UN, BSW, BSF and special forms, cut or rolled |
| Strength | Classes 10.9, 12.9 and 14.9; Inconel 718; B16 and other alloy grades |
| Standards | IFI 115, or your drawing |
| Testing | Ultrasonic testing (UT), MPI and full mechanical testing by UKAS-accredited laboratories |
| Finishes | Self colour, zinc, zinc nickel, zinc flake (Geomet, Delta Protekt), hot dip galvanising, electroless nickel, PTFE fluoropolymer, phosphate or passivation |
| Documentation | Certificate of conformity, EN 10204 3.1 or 3.2, test reports, dimensional reports and FAIR |
Materials
Materials we use
Certified bar from UK, EU and US mills. See all fastener materials.
- Inconel: 718, 625 and X750
- Carbon and alloy steels: EN24, EN26, 42CrMo4, B16 and classes 12.9 and 14.9
- Stainless steels: 17-4PH, FV520B and A453 660
- Incoloy: A286
- Titanium: titanium alloys
Manufacture and quality
Made in Willenhall, certified to release
Machined and threaded in our own Willenhall facility from certified UK, EU and US bar, with special processes managed by us through audited partners.
- Heat numbers traced from mill to release
- Heat treatment, NDT and coating by approved partners
- UKAS-accredited testing where specified
Related products
Related types
Questions
Frequently asked questions
What is a 12 point bolt?
A 12 point bolt has a head with twelve points, gripped by a 12 point socket. The compact head transmits high torque where there is little room for a spanner.
Why use 12 point bolts instead of hexagon bolts?
Because the head is smaller for the same thread size, 12 point bolts fit tighter spaces and suit high preload joints such as turbine casings. See hexagon bolts for comparison.
Can you make 12 point bolts in Inconel 718?
Yes. Inconel 718 is one of the most common materials for our 12 point bolts, with UT, MPI and mechanical testing as required.
What standard covers 12 point bolts?
IFI 115 is a common standard for 12 point flange screws. Most turbine and machine bolts are made to the OEM drawing, and we make both.
12 point bolt enquiry?
Send us the drawing or the standard
Send the drawing or a sample, with the material, testing and quantity you need, and we will quote quickly.