RS PRO BZP Plated Steel Countersunk Pozidriv Machine Screws From RS PRO a high-quality machine screw with a flat countersunk head for flush fitting and a versatile Pozidriv recess for a superior grip when tightening. This machine screw has a metric thread and is made from high-quality BZP (Bright Zinc Plated) steel which slows down rusting and corrosion What is a Machine Screw? A machine screw is similar to a bolt but has a socket or slot in its head that allows it to be turned by a screwdriver. The shank on a machine screw is straight rather than tapered with a full thread which is uniform along the entire length. Machine screws do not tap their own thread into materials like wood screws do but are designed to be fastened into pre-tapped holes in the parts they are fastening together. Having a threaded hole creates a stronger joint and results in a higher quality product. What is a Countersunk Screw? Countersunk machine screws, also known as CSK screws have a flat head design so when placed in a pre-drilled countersunk hole they will sit flush with or below the surface of the surrounding material. These screw heads are ideal for use when you need to cover the heads with a screw cap or create a flat surface for placing objects on or fixing other objects to. What is a Pozidriv Head Type? Pozidriv, sometimes shortened to Pozi, stands for “positive drive”. This head type has a cross recess in the center with four small indentations around it creating 8 points of contact. This design provides improved engagement and contact with the screwdriver and prevents ejection force when tightening or loosening the machine screw. What is Bright Zinc Plating (BZP?) BZP is a shiny coating is applied to the steel, this process prevents corrosion and rusting. If the application is situated within a harsh environment, BZP will provide much-needed longevity and reliability. Although it may not be as effective as stainless steel, the added benefit would be the price. As stainless steel is completely rustproof but expensive, BZP Steel offers a great solution and is massively cost-effective. Features and Benefits: Pozidriv head type for improved screwdriver grip Countersunk head for a flush finish Bright Zinc Plated steel for resistance to corrosion Meets DIN 965 Standards