A round top set screw is provided, including a first section having a shape of substantially a cylinder having a threaded side surface, a second section for wrenching drive, the second section formed contiguously and concentrically to the first section and having a shape of substantially a polygonal prism, and a third section formed contiguously and concentrically to the second section, the third section having a cylindrical portion and a round top having a convex shape, the edge of which contiguously connects to a side surface of the cylindrical portion, wherein the curvature of the convex shape is predetermined to prevent damages to a metal plate when it is pressed at an angle against the third section of the screw. A tool is provided for attaching the screw to a base board and securing it by using a corresponding nut. An apparatus including the screws for flattening a metal plate is also provided.