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).
Maximum Brinell hardness of steels for parts due to machining limitations.
| Identifier | ExFiles\Box 76\2\ scan0074 | |
| Date | 10th November 1915 | |
| H.H. 265 a (200 H) (S.B. 30. 12-10-15) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1278. X632 42 Mer To R.{Sir Henry Royce} from By.{R.W. Bailey - Chief Engineer} Copy to J.{Mr Johnson W.M.} November 10th. 1915. By2/H101115. RE BRINELL HARDNESS OF STEELS. Referring to your memo R10/1B51115. We note you state that a Brinell hardness of 400 is not too hard for certain parts under vibratory loads, in fact the majority of parts on car or Aero engine work. The maximum, however, that we are at present working to, is a Brinell figure of from 321 to 332, the higher Brinell hardness quoted above involves extreme difficulty in regard to machining, as all the parts with the exception of the road springs, are heat treated before machining as it is quite impossible, of course, to do any atretching with the [crossed out: wheels] parts as hard as quoted, so that at the moment it does not seem feasible for us to go any higher than 332. By.{R.W. Bailey - Chief Engineer} | ||