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 suitability and heat treatment processes for camshafts, Phantom III tappets, and rocker levers.
| Identifier | ExFiles\Box 142\4\ scan0182 | |
| Date | 11th November 1936 | |
| - 2 - In view of the foregoing, therefore, it is evident that the material is not suitable for making camshafts from, as under our present conditions it is necessary to do a fair amount of stretching. If, however, by spray quenching in an annular chamber we can prevent camshaft distortion then there would be some possibility of using the material for such a part, but it will demand good radii in all corners. PHANTOM III. TAPPETS. I think one can reasonably expect to produce these parts experimentally without the pieces being unduly brittle. I would suggest that for this particular piece the stem is protected. This would then have an ultimate hardness of 450 brinell approximately. The working faces would be carburised in the ordinary way, and the face attacked by the cam should be finally treated under the Cloudburst, so as to obtain a minimum brinell (V.P.N.) of 1000, the procedure for this part therefore would be to copper plate the stem, so as to protect it against carburisation during the carburising process. ROCKER LEVERS. These should be handled by such methods as to ensure the working face of the pad only, where it rests upon the cam being carburised. It is most important that there should be no carburisation on the back of the lever opposite the cam where the loads are higher. If the lever were copper plated it would probably be a sufficient protection, but it would have to be a good copper plating, and it would be necessary to check the levers to see that they were not above the brinell figure of 500 at any point other than the working faces, where again they should be finally treated by Cloudburst hardening to bring them up to a brinell figure of 1000 (V.P.N.) BY.{R.W. Bailey - Chief Engineer} | ||