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 defects in a clutch centre and proposing a change from nickel steel to carbon steel.
| Identifier | ExFiles\Box 129\3\ scan0187 | |
| Date | 6th April 1936 | |
| X110 <s>BY/TWD.{T. W. D???Aeith}</s> <s>c. Rm.{William Robotham - Chief Engineer}</s> <s>c. E.{Mr Elliott - Chief Engineer}</s> <s>c. Sft.{Mr Swift}</s> <s>c. Sft{Mr Swift}/Mr. Clay.</s> LC Smith I agree with By.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer} BY6/W.6.4.36. We are not satisfied with the clutch centre to which the flexible steel portion of the disc is affixed, the reason being that it has been specified by the Design Department in casehardening nickel steel. This has the following defects :- (a) The boss of necessity becomes bell-mouthed in quenching and, therefore, only fits for a short length on the centre of the boss. This is true even when a considerable amount of lapping has been done. (b) The outer rim to which the steel disc is secured, buckles as a result of the heat treatment, and so far we have not been able to overcome the trouble. My view is that this piece should be made in .600" carbon steel with a Brinell of 321. This material would be satisfactory on the hardened shaft, would be heat treated in the rough machined state and tempering, which is given as a part of the heat treatment, would ensure the piece not buckling when being finally finished off. One of these pieces made up in .600" carbon steel with the Brinell in question, should be instructed to the Experimental Department immediately. We would, therefore, like the Works to hand over one of these forgings as soon as possible. Incidentally, the Borg and Beck people insist that there is no necessity for hardening either pieces and, of course, our previous practice, has always been in line with this Borg and Beck idea. However, as we can produce a shaft hardened and quenched free from distortion, I see no objection to this feature being retained on the clutch centre shaft. BY.{R.W. Bailey - Chief Engineer} By | ||