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).
Analysis of a sample 'die cast' cast iron tappett from the Ford Motor Company, comparing its material composition and hardness to tappetts produced for the Wraith.
| Identifier | ExFiles\Box 158\4\ scan0204 | |
| Date | 14th January 1938 | |
| Mr. Jenner, c to Rm.{William Robotham - Chief Engineer} c to RHC.{R. H. Coverley - Production Engineer} A.{Mr Adams} Wiles SWDL{Len H. Swindell} 1360 RHC{R. H. Coverley - Production Engineer}/Vs.{J. Vickers}1/JT.14.1.38. Re- Ford Tappett. The following information has been obtained from the sample "die cast" cast iron tappett produced by The Ford Motor Company :- Tc. S. Cr.{Mr Cra???ster / Mr Chichester} Cu. Actual Analysis 3.72% .54% .57% NIL. Published " 3.75% .5 % NIL 1.0% Brinnel Hardness 470 - 508. from which it is apparent that Ford's have withdrawn the Copper addition in favour of the much more severe hardener Chromium. The fracture in the above would obviously be white throughout, thereby necessitating the machining operations being limited to grinding only. On the tappetts produced so far for Wraith we have maintained a grey fracture except on the face in contact with the cam, which has been hardened to white iron giving a brinnel of 530 minimum. RHC{R. H. Coverley - Production Engineer}/Vs.{J. Vickers} [Signature] | ||