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).
Material change for main switch armatures from Duralumin to mild steel due to supply difficulties.
| Identifier | ExFiles\Box 168a\2\ img338 | |
| Date | 22th June 1937 | |
| 6139 To Rm{William Robotham - Chief Engineer}/Wst. [Strikethrough text] [Strikethrough text] BY/RD.3/B.22.6.37. MAIN SWITCH - SEC.8160. Owing to the lag on the carbon armature, you will recollect that some time ago a new armature was standardised in Alum: Sheet to reduce the weight. There have been very great difficulties in obtaining pressings in Duralumin or RR.56 Sheet, and we have now arrived at the stage when no further material is available. In order to ensure continuity of production we have armatures made up in mild steel of thinner gauge, the increase in weight being only 1.5 grams, and we are handing to you herewith D.100564, one of these samples. Will you please have same built up into a switch in order to satisfy yourselves that the switch works satisfactorily. We have used a few of these on production on switches, and they have passed the production test quite satisfactorily. To enable us to order more pressings in mild steel and thus keep production going, will you please let us have your remarks as soon as possible. BY/RD. | ||