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The Range£15.71Visit shop Unifix Grade 12.9 Socket Head Cap Screws M4 X 40 - Q129120000400040270 - Box Of 200 - Grey
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The Unifix Grade 12.9 Socket Head Cap Screws are precision-engineered for professionals and DIY enthusiasts requiring high-tensile strength for demanding mechanical or structural assemblies. Built to strict DIN 912 standards with a resilient bright zinc plated finish, these screws provide excellent load-bearing capacity and corrosion resistance for heavy-duty applications; however, users should ensure they are using the correct metric hex key size to prevent stripping the socket head during high-torque tightening.
| Colour | Grey |
|---|---|
| Model Part Number | 1355398 |
| Brand | Unifix |
The 12.9 rating indicates a high-tensile strength steel, with a minimum ultimate tensile strength of 1200 MPa and a yield strength of approximately 1080 MPa.
They feature a bright zinc plating which provides basic corrosion resistance, but they are best suited for indoor use or protected, dry outdoor environments.
No, these screws require a metric Allen key (hex key) or a hex socket bit to fit the internal head design.
DIN 912 is a German standard that defines the dimensions, material, and mechanical requirements for socket head cap screws.
Yes, for critical structural assemblies, it is highly recommended to follow the torque specifications of the device or frame you are fastening to avoid over-tightening.
Ensure the hex key is fully inserted into the socket and is of the exact metric size; do not use worn-out tools.
Back the screw out and check for debris or burrs in the threaded hole; clear with a tap if necessary.
Clean the surface with a wire brush and apply a rust-preventative spray or grease to protect the affected area.
For installation, use a high-quality, hardened metric hex key or a hex driver bit to match the specific socket size of the M12 screw. Always start the thread by hand to ensure alignment and prevent cross-threading before applying the final torque with a tool. While the bright zinc finish offers decent protection, consider applying a thin layer of machine oil or anti-seize compound on the threads if the application is in an environment prone to oxidation. Store in a dry, low-humidity area to maintain the integrity of the zinc coating over long storage periods.
