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: JR
This page displays all the content on the website associated with the 'JR' model. Numeric models include all prefixes, such as 'Number', 'Mark', 'Size' etc.
Manuals for Model: JR
Rockwell Hardness Testers Models JR and J5. Operators Instruction Book.
Taylor Hobson "Model JR" 1 to 1 Copying, Profiling, Routing and Milling Machine. Operator's Instruction Manual. Includes a 32-page Taylor Hobson Accessories Catalogue (including cutter grinders) that not only illustrate the various items but give useful details of their function.