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).
Incorrect doming on battery ignition tungsten contact breaker levers, requesting they be ground flat.
| Identifier | ExFiles\Box 35\6\ scan 211 | |
| Date | 21th December 1925 | |
| To RHC.{R. H. Coverley - Production Engineer} from EFC. X2894 EFC3/T21.12. 25. BATTERY IGNITION TUNGSTEN CONTACT POINTS. X. 2894. Herewith we hand to you six battery ignition contact breaker levers fitted with tungsten contact points. Apparently the makers in grinding these have left the small doming on these lever points. We do not want doming on the lever points, but only on the screw points, and we already have screw points with doming. We should therefore be pleased if you would have the slight doming of the six lever points removed, i.e. the points ground dead flat. In regard to the doming on the screw points, there is now a drawing for this, D.51407, shewing the depth of doming as .003". The radius of doming, viz. 1.407" is also the same for the platinum screw points (D.51503), but owing to the smaller dia. of the platinum screw point, the depth of doming in that case is only .002". I think this corresponds exactly to the gauge which you made for us and which we hand you herewith, but I would like confirmation that the radius of this gauge is approximately the same as the 1.407" radius which is now shewn on these drawings. EFC. | ||