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).
Material test laboratory report on the failure of a Bentley Final Drive Pinion.
| Identifier | ExFiles\Box 109\1\ scan0174 | |
| Date | 3rd June 1941 | |
| To Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} Material Test Laboratory. H1/GLT.1/JK. 3.6.41. Failure of Bentley Final Drive Pinion. Piece No. GB.4958 Material S/ZNCR. Two adjacent teeth of the pinion had broken away completely, and the fractures showed that they had failed by fatigue. Nearly all the remaining teeth were cracked in a similar way, and appeared to be about to break off. The depth of case of a broken tooth was .034" and its hardness 58 C Rockwell. The hardness of core was 409 Brinell. All these figures are satisfactory, as was the material, as shown by fracture of the tooth. There is evidently, therefore, nothing wrong with the material or heat-treatment of the pinion. Failure must have been due to overloading during service. H1/GLT. | ||