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).
Diagram showing the results of a hardness test on a shaft and gears.
| Identifier | ExFiles\Box 98\4\ scan0110 | |
| Date | 5th July 1939 guessed | |
| FROM HPS{Horace Percy Smith - Experimental Factory Mgr}/RH{R. Hollingworth} c To RM{William Robotham - Chief Engineer}/GRY{Shadwell Grylls} HARDNESS TEST ON SHAFT AND GEARS 321 606 707 715 652 330 707 CENTRE GEAR | ||