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).
Cross-section diagram on graph paper showing a cast iron component with a chromium layer before honing.
| Identifier | ExFiles\Box 132\5\ scan0037 | |
| Date | 13th February 1939 guessed | |
| CHROMIUM NOTE RIDGE AT TOP AND TAPER AT BOTTOM. BEFORE HONING. CAST IRON | ||