A button head cap screw (also known as a cheese head) has cylindrical sides and a flat disc top that is similar to the surface of a wheel of cheese. They have a lower profile than standard socket screws and a larger bearing surface which makes them less likely to snag on moving machinery or equipment. They also have a deeper socket that can be used when the material in which they are being fastened is too thin to counter-bore. They are usually tightened with an Allen wrench (hex key).
Button head socket cap screws are used to generate a compressive load rather than the tensile load created by bolts and most other types of fasteners. This means they are good for holding components in place and standing up to vibration. They can be used in applications such as automotive, industrial equipment, electronic components and more.
They are commonly used in situations where there is not enough space to fit a standard socket head screw or the operator wants to avoid having a protrusion stick out from the fastened component. They are also a better choice than a flat head screw when the application is going to be subjected to vibration because the wider bearing surface of the button head can distribute the clamping force more evenly.
McMaster-Carr carries ISO 7380 Button Socket Head Cap Screws in property class 10.9, along with A2 and A4 Stainless Steel. They are available in a wide variety of lengths and diameters. button head cap screw