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OnBuy.com£6.58Visit shop Black Countersunk Hex Socket Bolts Din 7991 Iso 10642 Grade 10.9 Allen Key Flat Head Screws M4 To M8 5056826614315
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B&Q£9.78Visit shop B&Q - M4 X 12mm Black Hex Socket Countersunk Bolts (Pack Of: 10) Din 7991 / Iso 10642 Flat Head Allen Screws
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This guide is for professionals, makers, and DIY enthusiasts seeking durable and aesthetically pleasing fasteners. The key benefit is a secure, flush finish ideal for projects requiring a clean look. A potential caveat is the specific sizing measurement for countersunk heads, which differs from standard cap screws. These black oxide bolts offer precision, durability, and corrosion resistance, featuring a high-tensile carbon steel construction and a hex socket drive for easy installation. They are suitable for a wide range of applications from furniture assembly to automotive trim.
| Colour | Black |
|---|---|
| Model Part Number | M6 X 16mm |
| Brand | DIYUK |
Unlike standard cap head screws, countersunk screws like these are measured by their *total* length, including the head. Measure from the very top surface of the flat head down to the tip of the screw.
Grade 10.9 indicates a high-strength property class for steel fasteners, signifying a minimum tensile strength of 1000 MPa and a yield strength of 900 MPa. It's a measure of the bolt's durability and load-bearing capacity.
The black oxide finish offers some corrosion resistance, making them suitable for many outdoor applications. However, for prolonged exposure to harsh weather, especially coastal or high-humidity environments, stainless steel alternatives might be more appropriate for maximum longevity.
For an M6 Hex Socket Countersunk Bolt, you will typically need a 5mm Allen key.
To achieve a flush finish, the mating surface must be countersunk with a 90° countersink bit to match the angle and diameter of the bolt head. Ensure the countersunk hole is deep enough for the head to sit completely below the surface.
Yes, as they are made from carbon steel, these bolts are magnetic.
The primary advantages are a sleek, non-reflective black appearance that blends well with many materials and improved resistance to rust and corrosion compared to plain steel.
Ensure you are using the correct size hex key and that it is fully engaged in the socket. Do not overtighten beyond the recommended torque for the application. Use a high-quality tool.
Verify that the hole is properly countersunk to the correct angle (typically 90°) and diameter for the bolt head. Ensure no debris is preventing the head from seating fully.
Confirm that you are using the correct thread size (e.g., M6) for the tapped hole or nut. Ensure the hole is clean and free of obstructions. Start threading by hand to avoid cross-threading.
The black oxide finish provides moderate corrosion resistance. For highly corrosive environments, consider using stainless steel or applying a protective coating. Clean affected areas with oil and a soft cloth.
Setup: To install these bolts, ensure you have the correct size of hex (Allen) key for the drive type. Prepare the mating material by drilling appropriate clearance holes and, if a flush finish is desired, a countersink hole (typically 90°). IMPORTANT: When measuring for the correct bolt length, measure the *total* length from the top of the flat head to the very tip of the screw. This differs from cap head screws where length is measured from under the head.
Compatibility: These bolts conform to DIN 7991 and ISO 10642 standards, ensuring compatibility with standard M-threaded nuts, tapped holes, and tools designed to these specifications. They are compatible with a wide range of materials, including wood, plastic, and metal, provided the appropriate pilot holes and thread types are used.
Care: While the black oxide finish offers good corrosion resistance, prolonged exposure to harsh chemicals or saltwater may degrade the finish over time. For maintenance, wipe clean with a dry or slightly damp cloth. Avoid abrasive cleaners. If rust spots appear, they can typically be removed with a light application of oil and a soft cloth.
