Drilling metal

The action of drilling metal is to remove material from the hole in the form of two spiral sections and filings. It depends on the type of metal whether these spiral sections are removed as a continuous coil or as fine metallic particles. Soft brass, for example, when drilled leaves two wire strips. Iron and steel, on the other hand, are usually too brittle to assume this form, and so is thrown up as fine lumps. This waste material is known as swarf. The swarf is formed by the drill point being pressed into the metal while in rotation.