The apparatus is a rotatable bale forming roller for use in farm machines that form round crop bales. The roller is a cylinder with multiple ribs oriented parallel to the roller axis and formed in the roller surface. The roller is constructed with a frame of channel shaped members oriented parallel to the roller axis with the channel members interlocking with several discs oriented perpendicular to the roller axis. A thin high strength steel sheet is installed completely around the frame to form the surface of the roller, and the integral ribs are formed directly in the sheet. In the preferred embodiment, the ribs have leading surfaces oriented in planes that are radial to the axis of the roller, and the trailing surfaces of the ribs are oriented to form an acute angle with the leading surfaces.