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 3 1/2 Litre S.S. Gear Box with part numbers and gear tooth counts.
| Identifier | ExFiles\Box 126\5\ scan0155 | |
| Date | 8th March 1938 guessed | |
| 3 1/2 LITRE S.S. GEAR BOX SS{S. Smith} 93 S.S.63 S.S.45 27 TEETH 36 TEETH S.S.43 S.S.59 S.S.60 S.S.49 S.S.51 S.S.56 S.S.57 36 TEETH 37 TEETH 36 TEETH S.S. 48 16 TEETH REVERSE S.S. 58 21 TEETH. S.S. 63 28 TEETH S.S.54 38 TEETH S.S.55 30 TEETH 35 TEETH | ||