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).
The analysis and testing of Centricast AC6 and AC7 bearings.
| Identifier | ExFiles\Box 115\3\ scan0121 | |
| Date | 22th November 1937 | |
| Rm.{William Robotham - Chief Engineer} CHl. CRHC. cBY. cRm/Swdl.{Len H. Swindell} cHPS. 1020 Hs{Lord Ernest Hives - Chair}/ JWW.1/HM.{Capt. W. Hallam - Head Repairs} 22. 11.. 37. Centricast AC6 Bearings - Batch A.1. --------------------------- Further to our communication of 19th instant, reference Hs{Lord Ernest Hives - Chair}/JWW.4/HM.{Capt. W. Hallam - Head Repairs}, we have received an analysis from H1 and it appears that the Mg. is extremely low giving only .6%. In confirmation of our conversation with Rm.{William Robotham - Chief Engineer} and H1. it has been agreed to use these bearings as they represent a superior AC7 and they will be known for test purposes as AC7 DC, Batch A1. The brinell now showing is 65 and it has been decided by Rm.{William Robotham - Chief Engineer} that it is more suitable to use these bearings which show an increase of 20 brinell when manufactured by this process than the AC6 which is harder and reads approximately 70. This means that a bearing will be tested which is harder than AC2 but is not the maximum hardness that can be obtained. H1 suggests that we obtain what information we can from the present bearing and make the AC6 proper subject to a further investigation later. It has been agreed with H1 that we should make a series of tests to see how close the Mg. content can be controlled when the rejections limits shall be fixed on the analysis test on the test car when its trials are completed. HPS{Horace Percy Smith - Experimental Factory Mgr} is making a record of the brinells in the test car, and we shall be pleased to receive a copy when available. Will those concerned please note that the bearings now under test are to be known as AC7 DC. Will HPS{Horace Percy Smith - Experimental Factory Mgr} please see that the bearings in his possession are re-stamped with this number. In order to avoid any confusion a short history of these bearings is attached. [Signature] | ||