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).
Stress, testing, sourcing, and hardening of valve springs.
| Identifier | ExFiles\Box 80\3\ scan0139 | |
| Date | 10th February 1913 | |
| H.R. 235A (100H) (PP351. 2.1.13) G 4088 COPY. R1/B11213. C.J. from F.H.R. for Messrs. Wormald, Nadin & Elliott. Re Valve Springs. Will Mr. Elliott calculate (by our spring list) the stresses that the steel is subject to in other people's valve springs (roller on top of cam) and compare it with ours. Cars we have:- Mercedes, Napier. Can the test rig for these valve springs be run at a speed quicker and at a speed slower to see if it makes any difference, say 1500 - 1750 - 2000. I do not think much of the trial places for springs. Can we find out where DeDion, Metallurgique, Brazier or some of these people get theirs, including the successful English places like the Vauxhall, Sunbeam, Napier or other such people who bang their valves about at high speeds? Surely the steel delivered by Vicers could not be so bad if properly hardened and tempered, all springs free from flaws should be capable of being let down in temper until they would never break, but rather break their set after first rate hardening. I have suggested a salt bath furnace (I do not recommend the salt bath for hardening if this is found unsuccessful for other work, but for tempering. You will remember that in this state it is good for cooling high speed steel) the salt just molten or an oil bath with the special very highflash pump oil which is used in air-cooled engines, I think that there is some cell 800°F.{Mr Friese} - I have seen no results of tests. At present, I understand, we have very few breaks on the road but that we cannot get the spring to stand on the test rig which, if true, will enable us easily to pick out the best. F.H.R. 10/2/13. | ||