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).
Test results and re-classification of Centricast Test Bearings.
| Identifier | ExFiles\Box 115\3\ scan0122 | |
| Date | 22th January 1937 | |
| Hs{Lord Ernest Hives - Chair}/JWW.2/HM.{Capt. W. Hallam - Head Repairs} 22. 1.. 37. Centricast Test Bearings. ---------- 1. Produced as AC6 but later found to have lost Mg. and now coincide with the analysis of AC7. 2. Heat-treated at 160 - 170 for 20 hours showing a brinell of 54. 3. Given further heat treatment for 8 hours at 175 - 180 giving a brinell of 65. 4. Agreed to use these bearings and change the material stamp to AC7 DC. | ||