A concave grate, concave bar, or concave rod assembly and configuration for threshing operations of a combine harvester is disclosed having concave bars or rods configured at various angles and positions such that they maximize threshing throughput. The concave bar assembly can include an elongated bar having a semi-cylindrical or partially round configuration. Further, the elongated bar can include a partial cut-out, notch, or channel longitudinally extending the length of the elongated bar, and wherein the elongated bar can be configured to be secured to a concave of the combine harvester. Here, the partial cut-out, notch, or channel further can include a first sloped or raised surface. Further, the first sloped or raised surface can be configured to make contact with one or more grains of a crop material, thereby effectively and efficiently separating the one or more grains from the crop material.