Electric grinding machine used in grinding bearing surface of north and south pedestals of Pier No. 6. The surfaces of the concrete pedestals are ground to a true plane with a maximum divergence of about five-thousandths of an inch. After grinding a thin layer of pure red lead is applied to the surface of the concrete and a steel place-plate 4 inches thick placed thereon ready for erection of steel. Photographs. Description: six hundred and four photographs of the construction of the San Francisco-Oakland Bay Bridge.