A plate rolling machine can roll various kinds of metal sheet into a round or conical shape. Four-roller machines have a top roll, one pinching roll, and two side rolls.it can pre-bend the metal sheet to make it form perfect round. The side rolls do the work of bending. The pinching roll holds the plate. Three-roller machines (variable pitch aka variable geometry) have one pressing top roll and two pressing side rolls. All three rolls able to move and tilt. The top roll moves vertically and the side rolls move horizontally. When rolling, the top roll presses the metal plate between the two side rolls.