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).
Graph of safe stress ranges for valve spring wire, comparing Chrome-Vanadium and Carbon Steel.
| Identifier | ExFiles\Box 158\4\ scan0055 | |
| Date | 10th September 1936 guessed | |
| 1360 SAFE STRESS RANGES FOR VALVE SPRING WIRE STRESSES ALLOW FOR SURGE (IF ANY) AND ARE CORRECTED BY WAHL'S FORMULA CHROME - VANADIUM CARBON STEEL Y-AXIS: HIGHEST SAFE WORKING STRESS LBS/SQ. IN. X 10^-3 X-AXIS: LOWEST WORKING STRESS LBS/SQ. IN. X 10^-3 | ||