Rockwell Hardness Testers by the original US Wilson Company (then Acco Industries). Not a manual but a detailed explanatory Booklet from the 1980s describing how to determine which type of tester to choose for different jobs and materials with copious notes on the different types and methods to be used.
Model: GN
This page displays all the content on the website associated with the 'GN' model. Numeric models include all prefixes, such as 'Number', 'Mark', 'Size' etc.
