Certain bridge parts had to be finished to close tolerances, particularly the upper chord and end posts of the lenticular truss, where components came together at an angle. This was accomplished by means of a large planer, essentially a milling machine, in which the bridge parts were slowly fed past the teeth of a high-speed cutter. The end posts in the foreground of the shop view probably had the angle at the pin joint finished with the rotary planer. In the picture below, the ends of several I-beams are being finished at once.