Dear Mr. Knudsen and Mr. Hillman:
My recent discussions with you have emphasized in my mind the urgent necessity of expanding and speeding up the manufacture and use of critical machine tools. I have watched the steady and substantial growth of the machine-tool industry during the past months. At the same time I have seen the critical machines in our defense plants used in an ever growing number of hours each week. I know that this increase has been caused by the hard work of yourselves, of your associates, and of the men who manage and work in the plants throughout the Nation.
But it is not enough. The ever increasing demands for munitions, planes, and ships, caused by the critical situation which confronts our Nation, requires that they be produced in even larger quantities and ahead of the schedules assigned to them. It is essential that industry continue to increase the number of vital machines manufactured and that every single critical machine in the United States be used the maximum number of hours each week.
Every effort should be made to utilize to the very limit those critical machines; if they be in defense plants, by increased hours of operation on the work at hand; if in other plants, by finding defense items or parts for them to make or, as a last resort, by moving the tools to defense plants where they may be urgently needed.
Our problem is to see to it that there is no idle critical machine in the United States. The goal should be to work these machines twenty-four hours a day and seven days a week, relieving the machines only for such time as is required for overhauling and repair.
The country should be further combed for men who have had experience on these machines. We should ask them to transfer their efforts to this operation which is so essential to our defense. No effort or justifiable expense should be spared in speeding this program, in order to obtain the objective which our national interests require.
Workers and managers will, I believe, join with you with spirit and determination in pursuing and achieving this goal at the earliest possible moment.
Very truly yours,
Franklin D. Roosevelt, Letter Requesting Around-the-Clock Defense Production. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/209546