Conversion. Copper and brass processing. The inside of a large brass and copper tube mill. Copper tubes are made in many sizes, and in many alloys, and are needed for war production in hundreds of different ways--from small diameter tubing for gas and oil lines in airplanes and tanks and motor cars to large diameter tubes used in construction of our battleships. A tube annealing furnace may be seen to the right. Chase Brass and Copper Company, Euclid, Ohio