Abstract: A mill for rolling round bars, having a penultimate and a last stand with mutually perpendicular roll axes, is provided with a control system for varying the roll gaps of said stands and for axially aligning the rolls in the last stand. A gauge measures the diameters of the bar about its entire periphery and supplies a computer with this data. In addition, data, indicative of lengthwise variations in predetermined diameters of the bar, are supplied to the computer. The computer uses these data to compute an optimum diameter profile of the bar. The computer then calculates adjustments to the rolls in these last two stands to obtain this optimum profile. If substantial improvement in the performance of the mill can be obtained by these adjustments, the computer actuates means for adjusting these rolls whereby this profile may be realized.