Manpower. Veteran boring mill worker. Seventy-five-year-old George Shoemaker points to the only change ever made in the seventy-seven-year-old vertical boring mill on which he has worked for the past fifty-four years. The groove was cut to accomodate huge castings of lighthouse settings many years ago. The old machine was serving during the Civil and Spanish-American wars and World War I. It works seventy-six hours a week in this war, boring castings up to eleven feet square