The paper explores how novices in school-based vocational training make sense of computerized numerical control (CNC) machines. Based on two ethnographic studies in Swedish schools, one from the early 1980s and one from 2006, it analyses change and continuity in the cognitive, social, and emotional processes of learning how to become a machine tool operator. What and how students learn will become part of their self-understanding, future vocational identity, and sense of what they know. The paper discusses in detail the various tasks involved in learning CNC and how students and teachers understand and handle their everyday encounters with the machines. The study combines a situated learning perspective with one from science and technology studies, which focuses on how a technology's script is made workable, or "localized", as part of ongoing activities and interactions in the school.