Solid drawn pipes, both of steel and copper, of diameters up to 6 in. or 7 in., can now by the aid of hydraulic or other bending machines be bent to form bends of various shapes, so that simple pipe bends made up out of sheet metal and brazed or riveted are not so common as formerly. Bends for pipes of large diameter, however, have to be made up, and also those for small pipes where no facilities exist for pipe bending. We shall, therefore, now consider a few typical cases of bends, tee-pieces, etc.