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).
Letter to Alford & Alder (Engineers) Ltd. regarding chromium plating and thread specifications.
| Identifier | ExFiles\Box 137\5\ scan0173 | |
| Date | 7th October 1937 | |
| 100+.200B 1159 Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls}/7/R.{Sir Henry Royce} 7th October, 1937. Messrs. Alford & Alder (Engineers) Ltd., Deacon Street, Walworth, S.E.17. Dear Sirs, Ref: VAG/MM/2552. We thank you for your letter of October 6th. As regards the Chromium plate, the primary nickel deposit should be .002 to .0025 thick, and this before Chromium Plating should not show any blue spots after being for 10 minutes at room temperature in contact with filter paper soaked in a solution of 5% Hydrochloric Acid and 0.2% Potassium Ferricyanide. We have no test after the Chromium has been added. The form of a thread on the hub and in the cap should be B.S.A. standard form of 55° truncated as mentioned on the drawing by screwing to a larger diameter than the piece has already been turned. We hope this gives you all the information you require. Yours faithfully, For ROLLS-ROYCE LTD. | ||