Manufacturing tolerances and material hardness for the Wraith III gearbox 2nd speed coupling.
| Identifier | ExFiles\Box 8\11\ 11-page082 | |
| Date | 21th May 1937 | |
| SECRET. 628 Copy to Mr. [REDACTED] Mr. [REDACTED] Rm. {William Robotham - Chief Engineer} HPS. {Horace Percy Smith - Experimental Factory Mgr} Mr. [REDACTED] E {Mr Elliott - Chief Engineer} /HDY. {William Hardy} 1/M.21.5.37. WRAITH III. GEARBOX. Referring to the 2nd speed coupling, we have been asked by the Operation Planning Dept. whether the keyways in the universal ring which engage with the two splines on the layshaft can be/left soft to facilitate manufacture in view of the small tolerance to be worked to. We have agreed to this being instructed. The material should be left as at present instructed, i.e. S/SZX. It can be changed to S/ZNCR. if found necessary for greater hardness. The sides of the ring can be left soft over the whole area. E {Mr Elliott - Chief Engineer} /HDY. {William Hardy} | ||
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).