Determination of Inherent Stresses by Measuring Deformations of Drilled Holes
This is a 1933 NASA technical report on determining inherent stresses in metal by measuring how drilled holes deform, written for engineers and researchers in materials testing and aeronautics. The first picture shows a laboratory measuring instrument with a microscope head mounted on a bracket above a clamped specimen, and the second is a graph plotting compressive and tensile stress values against each other with data points on curves. A designer might take from them the plain technical look of early engineering reports: mechanical apparatus photographed against a neutral background and clean line graphs with gridded axes and labelled units.
