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).
Specifications for the doming of platinum and tungsten battery ignition contact points.
| Identifier | ExFiles\Box 61b\1\ scan0046 | |
| Date | 21th June 1927 | |
| X6118 X.919 21.6.27. X.4652. X.2894. DOMING OF PLATINUM AND TUNGSTEN BATTERY IGNITION CONTACT POINTS.(SCREW). The following figures have been finally fixed :- Dia. of std. platinum point = .150" Dia. of tungsten " = .175" Dia. of doming for platinum screw point = 5.625" or radius 2.812" Dia. of doming for tungsten screw point = 7.650" or radius 3.825" These correspond in each case to a heighte of doming of the centre of the surface of the point above the circumference of .001". The D.{John DeLooze - Company Secretary} numbers are as follows :- For tungsten :- D.51407 - Screw point with .001" doming. D.51408 - Lever point - flat. For platinum:- D.50467 - Screw Point - flat. D.51056 - Lever Point - flat. D.51503 - Expl. plat. Screw Point with .001" doming. EFC. | ||