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).
Standard dimensions and limits for oversize valves.
| Identifier | ExFiles\Box 35\3\ scan 014 | |
| Date | 12th June 1920 | |
| To Hm.{Capt. W. Hallam - Head Repairs} from R.{Sir Henry Royce} Copy to CJ. " " Bn.{W.O. Bentley / Mr Barrington} " " Hs.{Lord Ernest Hives - Chair} X4432 R16/G12.6.20. 4432 X.2764. RE OVERSIZE VALVES. With reference to your memo HM{Capt. W. Hallam - Head Repairs}24/W4.6.20, supposing we make our limit .025", this being one of our standard dimensions. It is probable that you might have two sizes, and in this case they would be .015" which I understand you have already standardised, and the .025" the suggested extreme limit. I should not anticipate any trouble even in going further than this rather than scrap a block of cylinders, but it would be a pity to make a standard larger than was necessary. Mr. Hives will perhaps test whether he can detect any fault in the larger valve stem. R.{Sir Henry Royce} | ||