⚙️ Grade 12.9 High Tensile Socket Cap Screws – Allen Head Bolts M8 & M10 | DIN912
🏷️ Brand: HomeDIYer Fastener | DIN912 | Grade 12.9 Alloy Steel | Uncoated | Hex Bits Included
📌 Overview — Extreme strength for the most demanding bolted joints. When standard fasteners fail under high load or vibration, upgrade to Grade 12.9 High Tensile Steel Socket Cap Screws. With a tensile strength of 1220 MPa (177,000 psi), these DIN912 bolts are among the strongest metric fasteners available. The cylindrical head and hex socket drive allow high torque application without slipping, and the sleek profile fits perfectly into counterbored holes. Ideal for heavy machinery, hydraulic systems, racing components, industrial tooling, and structural applications where failure is not an option. Available in M8 and M10 diameters, fully threaded up to certain lengths, then partially threaded for longer sizes. Each order includes the correct hex screwdriver bits. Choose your length and quantity – engineered for professionals who demand the best.
✨ Key Features of Grade 12.9 Socket Cap Screws
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Grade 12.9 High Tensile Alloy Steel – 1220 MPa tensile strength, 1100 MPa yield strength – the highest metric property class for steel fasteners.
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Hexagon Socket Drive (Allen Key) – Enables high torque transmission without cam-out; bits included with your order (6mm for M8, 8mm for M10).
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DIN912 Standard – Precision dimensions for reliable fit in counterbored holes and with standard metric nuts.
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Cylindrical Head Profile – Clean, low-profile appearance; ideal for machine assembly and recessed installations.
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Fully threaded up to 35mm (M8) / 40mm (M10) – Longer lengths are partially threaded with a plain shank under the head (standard DIN912 practice).
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Metric Coarse Threads M8 & M10 – Most common pitches (1.25mm for M8, 1.5mm for M10).
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Uncoated Black Finish (Self-Color) – Natural steel with light oil for storage; suitable for dry or oil-lubricated environments.
📏 Technical Specifications – Grade 12.9 Socket Cap Screws (DIN912)
| Thread Size |
Thread Pitch (mm) |
Head Diameter (mm) |
Head Height (mm) |
Allen Key Size (mm) |
Thread Type |
| M8 |
1.25 |
13.0 |
8.0 |
6.0 |
Fully threaded ≤35mm; partially threaded >35mm |
| M10 |
1.5 |
16.0 |
10.0 |
8.0 |
Fully threaded ≤40mm; partially threaded >40mm |
💡 Length & ordering info: Screw length is measured from the underside of the head. For M8: lengths up to 35mm are fully threaded; longer sizes have a plain shank. For M10: up to 40mm fully threaded; longer = partial thread. Choose your preferred length (e.g., 16mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm) — sold as per your requirement. Hex bits are included with your order.
⚠️ Material note: Grade 12.9 steel offers exceptional strength but is not corrosion-resistant. The uncoated black finish (self-color) has light oil to prevent rust during storage. For indoor, dry, or oil-lubricated applications (engines, machinery, tooling), these are ideal. For outdoor or wet environments, use stainless steel or apply a protective coating.
❓ Frequently Asked Questions – Grade 12.9 Socket Cap Screws
What does Grade 12.9 mean? How strong is it?
📊 Grade 12.9 is the highest metric property class for steel fasteners. Minimum tensile strength: 1220 MPa (177,000 psi), yield strength: 1100 MPa (160,000 psi). For comparison, Grade 8.8 is about 800 MPa, and A2-70 stainless is 700 MPa. These are the bolts to use when maximum strength is required.
Are these screws fully threaded or partially threaded?
🔩 It depends on length. For M8: lengths ≤35mm are fully threaded; >35mm have a plain shank under the head (partial thread). For M10: ≤40mm fully threaded; >40mm partial thread. This is standard per DIN912. If you need fully threaded in longer lengths, please contact us for custom orders.
Do you include the hex bits? What sizes?
✅ Yes, the box includes the correct hex (Allen) bits: 6mm for M8 screws, 8mm for M10 screws. You'll have everything needed to install them right away.
Will these bolts rust? Are they suitable for outdoor use?
🌧️ Grade 12.9 steel is not stainless – it will rust if exposed to moisture. The uncoated black finish has light oil for storage, but for outdoor or wet environments, we recommend applying a rust-preventative coating (e.g., paint, zinc spray) or switching to A2/A4 stainless steel socket cap screws. These are best for dry, indoor, or oil-wetted applications like machinery, engines, and tooling.
What lengths are available? Can I order custom lengths?
📦 “As per Your Choice” – select the exact length you need. Common lengths: 16mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm. Custom lengths available for bulk orders – contact us with your requirements.
⚙️ HomeDIYer Fastener — Extreme-strength fasteners for critical applications. Order your exact size, length, and quantity today.
