Hex Socket Countersunk Bolts - M8 x 30mm - Black

Countersunk bolts are measured from the very top of the flat head down to the tip of the screw. Unlike cap head screws, the head height is included in the overall length measurement.

These bolts are made from High Tensile Carbon Steel, specifically Grade 10.9, which indicates a high level of strength and durability.

The black oxide finish provides enhanced corrosion resistance compared to plain steel and offers a clean, non-reflective, professional appearance.

For M6 Hex Socket Countersunk Bolts, you will typically need a 5mm Allen key. Always confirm with the specific tool manufacturer's recommendations.

Yes, the black oxide finish offers some corrosion resistance suitable for many outdoor applications. However, for prolonged exposure to harsh weather or coastal environments, stainless steel alternatives may be more durable.

These bolts conform to the DIN 7991 / ISO 10642 international standards.

As they are made from carbon steel, these bolts are magnetic.

Ensure the countersink hole is correctly sized and angled (90 degrees) for the bolt head. Check that debris is not obstructing the seat.

Verify you are using the correct size hex key. Ensure the socket is clean and free from obstruction. Check for damage to the hex socket on the bolt.

Back the bolt out and inspect the threads on both the bolt and the receiving hole. Ensure you are not cross-threading. Use lubricant if installing into hard materials. Do not force the bolt.

The black oxide finish provides moderate corrosion resistance. For harsh environments, consider a stainless steel or coated fastener. Clean affected areas and apply a rust inhibitor if necessary.