Drop hammers fall with ground-shaking concussions. The planishing machine makes a staccato racket that would drown out a couple of machine guns. The operators pay no attention to these shattering factory noises.
They are deaf-mutes. To North American Aviation (as to many other plants now employing them) their unique usefulness was as much a surprise as the successful use first made by Brewster Aeronautical of midgets to work in tight places.
To talk to them the foreman need not travel across a long room and shout instructions. Instead he taps a shoulder near him, points to the man he wants. This...