An Analysis of the Identification Value of Defects in IBM Selectric® Typewriters

Twenty-one IBM Selectric® Model 72 typewriters were examined for the presence of identifying defects. The purpose of the study was to determine if Selectric typewriters of a similar age and history of use could be differentiated on the basis of alignment defects. It was found that the typewriters involved in the study could be differentiated using standard typewriter identification techniques.