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).
The 'Tocco' crankshaft hardening process, including material tests, cost analysis, and implementation timelines.
| Identifier | ExFiles\Box 148\5\ scan0217 | |
| Date | 12th November 1937 | |
| -4- RHC{R. H. Coverley - Production Engineer}/SB.{Mr Bull/Mr Bannister}1/MJ.12.11.37.Cont'd.{John DeLooze - Company Secretary} this hollow copper clamp which is connected to a high pressure water supply, and in about four seconds the pin or journal reaches red heat for a predetermined depth (about .125). The current is then automatically turned off and the water turned on which quenches the steel and gives a surface Brinell of over 600, after which the crankshaft is tempered in oil at 150°C. for two to three hours. Each journal is treated individually and the crankshaft is rolled on its trolley through a sheet metal tunnel where hardening clamps are arranged at intervals. A sample of 'Tocco' hardened material has been Laboratory tested and found to have surface cracks, but this may have been due to the fact that it was hardened to an excessive depth and in any case it does not appear that the saving obtained by using 'Tocco' hardened .40 carbon steel crankshafts is sufficient to justify development work. From the attached Costs Analysis it will be seen that Phantom lll crankshaft in V.C.M. with loose balance weights to LdC.5230 provides a saving of £4. 2. 6d. per chassis which becomes effective (when the tool cost is recovered) after producing 200 cars. This shaft cannot be introduced until the first chassis in 'E' Series, commencing January 1940; due to existing stocks and the saving will therefore not become effective until January 1942 on a production of two Chassis per week. RHC{R. H. Coverley - Production Engineer}/S. Bannister. | ||