The pictures below are of two editions of a manual used for training in the Henry Ford trade school in Dearborn Michigan The soft cover manual is from 1941 / 1942. The hardbound one is post 1942. Since the hardbound edition was edited in 1941 and 1942 it places the publishing of the soft cover version nicely.
Anyone with additional interest in these can PM me.
Anyone with additional interest in these can PM me.