Replaceable refiner fillings used for refining of lignocellulosic and other natural and synthetic fibrous materials in the manufacture of paper, paperboard, and fiberboard products. The refiner fillings include a pattern of blades and spacers defined by a bar cluster, with the bar cluster being the basis of formation of the filling. A method of manufacture provides bar cluster patterns based on factors including pumping angle, plurality of segments in a refiner filling, and the number of clusters in a segment. A bar set cluster is established for uniform fabrication of bar clusters for the refiner fillings.