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).
Letter to a supplier regarding the failure analysis of fractured steering rollers.
| Identifier | ExFiles\Box 153\1\ scan0223 | |
| Date | 30th March 1939 | |
| 1300 (Experimental Dept.) RM{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}15/JH. 30th March, 1939. The Hoffmann Manufacturing Co.,Ltd., Chelmsford, ESSEX. For the attention of Mr. C.H. Smith. Dear Sirs, We are posting to you to-night, under separate cover, the following parts of fractured steering rollers:- (a) Complete assembly with outer race cracked and small portion broken out. Failure occurred on new production car under 25% overload. (b) Larger portion of broken roller. This roller was broken to examine fracture and is one of three special sample rollers (No.N.3294) sent to us recently made from bar S.82 material supplied by us. (c) Small portion of roller which failed on customer's car on service in France. We think you will agree that the fracture on portion (b) shows a totally different material condition to these of portions (a) and (c). We have been analysing the material of a number of rollers with the following results to date:- 2 rollers show 4.25 nickel, 1.27 chromium, while 2 others show 3.5 nickel and 0.7 Chromium. It therefore appears that at least two steels have been used for these rollers. | ||