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).
Valve spring design, materials, and potential suppliers in comparison with American practice.
| Identifier | ExFiles\Box 96\2\ scan0157 | |
| Date | 23th October 1936 | |
| D 354 GRG LE Smith To EV.{Ivan Evernden - coachwork} from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD}..HS.{Lord Ernest Hives - Chair} c. Rm.{William Robotham - Chief Engineer} F/JNR.{Charles L. Jenner} E/Sn.{Mr Sanderson} re Valve Springs. With reference to the subject of valve springs in Carbon steel, we attach herewith a very interesting report from Mr Donkin, Chief Engineer of the Eaton Spring Co. of Cleveland. You will notice the statement that the American valve spring wire is supplied by Swedish wire manufacturers, the reason being that their product has an excellent surface, and free from decarburisation. A table of typical American design practice on valve spring stresses is given, and we have added to this our Phantom III figures. These figures show that the valve spring design on the Phantom III is on the easy side compared with American practice. We do not quite understand the treatment recommended for oil tempered wire mentioned in the last paragraph but one, but it appears to be a sort of tempering applied after a settling operation carried out by surging the spring for equalising any set up stresses. I think we ought to instruct some of the standard Phantom III springs E.87498 in the recommended "Oteva" wire made by The A-B Garphytte Bruck, Garphytten, Sweden, and also some of the experimental springs to LsC.5323 in the same material. The former should give us a value for the wire compared with our own product, and the latter is required for getting a value for design variations. In connection with the question of obtaining supplies of this wire, we also attach a letter from the Swedish Vice-Consulate at Birmingham giving the addresses of two firms in this Country who are agents for the Swedish oil tempered wire, but it might be as well to approach the | ||