English: Aircraft factory, Chullora. Every piece of metal used in the Beaufort is stringently tested. These women workers are using the Rockwell hardness test on sheet metal. The point of the machine presses on the metal and a simple reading of the dial gives the result. If the metal is too soft for use, it is placed in a normalising bath. Brought to a temperature of 490 degrees centigrade, the metal is made softer than when put back into the bath. When removed and kept at ordinary day temperatures, the metal hardens 90% in two hours and another 10% in the succeeding five days. The testing machinesare made in the U.S.A.