A concave separator or concave separation grate assembly and configuration for separating operations of a combine harvester is disclosed having integrated, interchangeable, and removable finger-like like configurations and assortments that can allow full separation of crop material from chaff, straw, vines and the like, thereby increasing grain separating capacity in a combine, improved breaking up the chaff-grain material, among other advantages. The separator grate assembly can include a bracket or grate member, and a plurality of first protruding members secured to the bracket member and having a first configuration, the first protruding member having a proximal end and a distal end. The first protruding members can include an elevation or angle relative to a horizontal plane when secured to the bracket member, and wherein each of the plurality of first protruding members can be equally spaced apart from each other when secured the bracket member.