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).
Cross-section diagram of a gearbox shaft featuring an oil retaining thread.
| Identifier | ExFiles\Box 148\4\ scan0140 | |
| Date | 2nd April 1940 guessed | |
| GEARBOX. OIL RETAINING THREAD. | ||