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).
List of design and manufacturing changes, comparing Derby and American practices.
| Identifier | ExFiles\Box 29\2\ Scan068 | |
| Date | 11th November 1922 | |
| - 8 - BY2-F1.11.22. contd. (7) Engine Coupling. The universal joints of the engine coupling are held centrally by spherical ends on the 1st motion shaft and the clutch hub respectively which are produced to a close limit. These spherical surfaces also help to take up the wear due to the weight of the coupling. For cheapness america have made the spherical surfaces clear; the result is the joint can be .010" eccentric and the wear of the joints will accumulate more rapidly. (8) Crankcase. The inside of the crankcase has always been scraped, with a view to eliminate all dirt and loose particles - America are sand blasting - the result of this will be that particles of sand and metal will be left on the surface, however they may be washed, and will contaminate the oil and cause increased wear and tear - this change considered most undesirable. (9) Gearbox. Here again sand blasting has been substituted for hand fettling and scraping, and is equally bad in this case as in the crankcase. (10) Pivots. Lightening hole at the outer end of the axle pivot has been eliminated. This increases the wear of chassis. (11) Clutch hub. Being produced in nickel steel instead of C.H.N.S. owing to policy of clearing the universal joint from bearing on this unit. (12) Air Pump. R's design included a very carefully considered scheme for a piston produced in C.H.N.S. carefully hardened, ground and polished. America have replaced this excellent piece of designing by an ordinary cast iron piston. (13) Case Hardened Parts. A large number of parts have been produced to size, and in order to try and control the carburising claying has been resorted to. In some cases this is permissible, in other cases it is undesirable. In the case of the tappet guide for instance, the method used by Derby was resorted to owing to breakage occurring due to the material becoming too brittle when using the scheme now in use in america. | ||