Secondary tooling methods include trepanning, skiving and burnishing, pull boring, or bottle boring. One-piece finned heat sinks are produced by extrusion, casting, skiving, or milling. Other terms for truancy include playing hooky (American English), skiving off (British English), and bunking. In Liverpool, "bunking" or "cutting class", "doggin", "skiving", "playing tickie" or "puggin". In Ireland, "mitching", "on the hop", "dossing", "on the duck" or "skiving". This process can happen on a deep hole drilling machine or a dedicated skiving machine. One-piece copper heat sinks can be made by skiving or milled. It ends up with Renton narrating; he's been skiving on the car deck, smacked out. There is also a skiving tool that can be used for light finishing cuts. Additionally, the skiving process also increases the roughness of the fins. Skiving requires a minimum material feed rate to cut successfully. Skiving is also used for the manufacturing of heat sinks for PC cooling products.