Understanding Metric Button Head Cap Screw Sizes | ShunTool
These screws are typically made from stainless steel, carbon steel, or alloy steel to maximise durability and anti-corrosion properties. Button head cap screws are available in a range of sizes, with the most common metric sizes falling between M2 and M10. The size of a screw refers to the diameter of the thread, which is measured in millimetres.