Countersunk Screws

Countersunk screws have been specifically designed to sit flush to the surface of the application that they are being fastened to. They feature a flat screw head, which has a sloping, conical bottom. This has been shaped to fit into the countersunk holes that must be drilled into the application's surface before installing the screw. Other common types of screws, such as the socket head screw or the button head screw would not fit flush to the surface that they are drilled into. This means that the screw head would stick out and not be flat against the object they were drilled into. Countersunk screw heads on the other hand, will sit flat against the drilled surface.

Stainless steel countersunk screws are often differentiated by the type of recess that is found on the screw head. As part of our standard catalogue, we sell five different styles of stainless steel countersunk screws. This includes countersunk hex screws, countersunk phillips screws and countersunk pin torx screws. We also offer stainless steel countersunk machine screws with a slot drive and countersunk machine screws with a torx recess. Machine screws have been designed for increased precision and mechanical strength and are generally better for fastening in metals or other hard materials. If you require a dimension or style of screw that isn't listed please get in touch, as we are often able to source additional requirements.

Stainless steel countersunk screws are often also described as stainless steel countersunk bolts. Many people will use the terms screws and bolts to describe the same fastening product. Additionally, customers will typically refer to them as simply, stainless countersunk screws or stainless countersunk bolts.

We are pleased to sell all of the commonly requested sizes of stainless steel countersunk bolts that customers find most useful for projects in the UK market. This includes the popular m5 stainless steel countersunk bolts. We also supply these in the commonly requested m5 x 70 and m5 x 60 thread lengths. In addition to this, we stock m4 stainless steel countersunk bolts and m6 stainless steel countersunk bolts, which are another customer favourite. Our range of metric thread sizes begins at m3 and increases at intervals up to m24. If you require a size or thread length that isn't shown, please contact us.

Stainless steel countersunk bolts are used primarily for their excellent resistance to corrosion and their ability to combine a secure fastening with a clean looking finish. Stainless steel countersunk screws are not a cheap fastening solution. However, the balance of durability, performance and clean aesthetics that they provide has led to them being used commonly across a wide range of industries and applications in the UK. You may see stainless countersunk bolts used in construction, to secure panels, cladding and roofing materials. Stainless countersunk screws are frequently used in woodwork, because they allow assembly of furniture, cabinets and other wooden pieces without any visible protrusions along the surface of the wood. Similarly, A4 marine grade countersunk screws are a popular fastening solution on boats and ships. Their ability to resist saltwater corrosion and simultaneously offer an aesthetic finish flush to the boat's surface is particularly valued on luxury vessels.

An M8 screw has a nominal major diameter of 8mm, which is the measurement across the outer edge of the threads. The standard coarse thread pitch for M8 screws is 1.25mm, meaning there's a 1.25mm distance between adjacent thread peaks. The minor diameter (core diameter) is approximately 6.647mm, whilst the pitch diameter sits at 7.188mm. When specifying M8 screws, the full designation appears as M8×1.25, though the pitch is often omitted when referring to standard coarse threads. These dimensions conform to ISO 262 metric thread standards, ensuring compatibility across different manufacturers and applications.

Stainless steel countersunk screws provide excellent corrosion resistance, making them ideal for outdoor, marine, chemical and high-moisture environments. Their flush-fit head design offers a clean aesthetic while maintaining strong mechanical performance. This combination makes stainless steel countersunk screws a preferred choice for long-lasting, professional-grade installations.

Stainless steel countersunk screws should be used when strength, durability and corrosion resistance are essential. They outperform nylon and zinc-plated screws in demanding environments such as construction, metalwork, automotive engineering and outdoor applications. If the installation may encounter moisture or requires long-term stability, stainless steel is the most reliable choice.

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