High Quality Content by WIKIPEDIA articles! An oiler is a worker whose main job is to oil machinery. In previous eras there were oiler positions in various industries, including maritime work (naval and commercial), railroading, steelmaking, and mining. Today most such positions have been eliminated through technological change; lubrication tends to require less human intervention, so that workers seldom have oiling as a principal duty. In the days of ubiquitous plain bearings, oiling was often a job description in and of itself.