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).
Investigation into cracking on brush holders, concluding it is not season cracking and recommending a change in material.
| Identifier | ExFiles\Box 50\5\ Scan216 | |
| Date | 11th September 1923 | |
| BY7-P11.9.23. - 2 - find the same results in cars running on the road that have occurred on the dynamo you have run on bench test, then, in my opinion, it will be definitely necessary to consider changing to the sheet-brass type of brush holder which we have produced, as, and when these become available in our various depots or repair dept. I proved that the effects were not season cracking effects and were therefore independent of the material itself, by carefully examining the remainder of the material on one of the broken brush holders. The rest of the material tested was perfectly ductile and shewed no signs of overstress from rolling and cold working, conclusive evidence that season cracking could not have occurred. BY.{R.W. Bailey - Chief Engineer} Ry | ||