In structural steelwork, after the draftsman has completed the detail drawings they are sent to the foreman of the structural department, who assigns the work to the layers-out. The proper I-beam or channel beam is selected and cut into lengths and the places for the rivet holes are marked off. If cutting to a certain shape is required, this shape is marked on the steel. The work, after it is laid off, is sent to the punchers, cutting-off machines, or drill presses. Here the pieces are cut to size and shape, holes are punched or drilled, and everything is done to put the work in shape for the assemblers. When the parts are ready to be assembled, they are riveted by means of riveting machines operated by compressed air. After the ends have been faced off, the work is ready to be painted and erected. Men known as erectors put the beams in place and supervise the riveting of them by the riveters.