A helical bar concave (20) comprises a grate (24) having helical mounting framework (42) and helical cutouts (34) to form a percent open area having a helical geometry. Configurable and segmented rub bars (36) are mounted in a helical fashion to a cylindrical helical surface (38/40) of the grate. There is provided a method of manufacturing a helical bar concave (20) from a flat, rolled laser cut arrangement that provides a net helical concave functionality. Laser cutting a flat metal sheet to form helical cutouts (34) defining a percent open area having a helical geometry in combination with configurable rub bars (36) mounted in a helical fashion results in a configurable helical bar concave (20) in which the number or aggressiveness of the threshing surface (38) on the inside radius of the grate may be changed and/or the rub bars (36) may be moved to the outside of the grate to change the percent open area and hence the separation characteristics of the concave.
