Hexagon socket countersunk head screw

Understanding the Countersunk Geometry

The defining feature of the Hexagon Socket Countersunk Screw is its head. Unlike cap screws or button heads which sit on top of the material, the countersunk head is shaped like an inverted cone. This requires the hole in the workpiece to be "countersunk"—machined with a matching conical chamfer. This design is critical for applications where parts must slide over one another without interference, such as in wear plates, guide rails, or flush panels.

Design Considerations (DIN 7991)

Load Bearing Capacity: It is important to note that due to the geometry of the flat head, countersunk screws have a slightly different load distribution than cap screws. They are excellent for centering the part (the cone shape self-centers the screw in the hole), but they generally have a lower maximum load capacity than a standard cylindrical cap screw of the same size. Standard Angle: Our metric countersunk screws typically feature a standard 90-degree inclusive angle. This is the international standard for metric fasteners. Please check your countersink tool to ensure it matches this angle for a perfect flush fit.

Quality Assurance

Product reliability is essential. We can provide an EN 10204 3.1 Material Certificate upon request to verify the chemical composition of the material batch. Please note that third-party inspection services require an additional fee.

Common Industrial Applications

Countersunk screws are utilized wherever a smooth surface is required:

• Machinery Slides: Securing wear strips and guides where moving parts pass over the screw head.
• Aerospace & Automotive: Aerodynamic exterior panels where air resistance must be minimized.
• Consumer Products: High-end electronics and furniture where visible screws must look integrated and sleek.
• Tooling: Fastening jigs and fixtures that require a flat base.

Frequently Asked Questions

How is the length of a countersunk screw measured?

This is the most common mistake in purchasing. Unlike other screws (where length is measured from under the head), countersunk screws are measured by their total overall length, including the head. This is because the entire screw sits inside the material. For example, an M6 x 20mm countersunk screw is 20mm long from the flat top to the tip.

Do I need a special tool to drill the hole?

Yes, you need a "countersink bit." First, you drill the clearance hole for the thread, and then you use a 90-degree countersink bit to create the conical recess for the head. If the recess is too shallow, the head will stick up; if too deep, the head will sink below the surface.

Can I use a countersunk screw in a non-countersunk hole?

Technically yes, but it is bad practice. If you screw a countersunk bolt into a flat hole, the cone shape acts like a wedge. As you tighten it, it exerts massive outward force that can easily crack the material (especially cast iron or plastic) or deform the thin sheet metal.