From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Chart showing the results of Brinell hardness tests on a component.
| Identifier | ExFiles\Box 48\4\ Scan138 | |
| Date | 12th August 1924 guessed | |
| Chart of Brinell tests made on Rockwell Hardness Tester with 1/16" steel ball and a load of 150 Kg. Numbers on diagram: 381 227 202 249 194 231 242 247 250 A B Key to position of section - shaded part distorted. | ||