Bar & Angle Rolling Our Roundo model R5 rolling machine can roll a wide variety of shapes. Type Maximum Size Flats 3/4″ x 5″ Squares 2 1/2″ x 2 1/2″ Rounds 2 3/4″ Angles 4 1/2″ x 4 1/2″ x 1/2″ Channels 8″ I-beams 8″ Tubes 4″