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).
Investigation into a cracked pressure ring from a 20/25HP Chassis clutch.
| Identifier | ExFiles\Box 103\1\ scan0078 | |
| Date | 1st March 1934 | |
| To Hs{Lord Ernest Hives - Chair} from Mx.{John H Maddocks - Chief Proving Officer} x5300 Mx{John H Maddocks - Chief Proving Officer}21/T1.3.34. 20/25HP. Chassis - Pressure Ring G55792. During the test of a 20/25HP Chassis yesterday, trouble was experienced in disengaging the clutch at high speeds - on dismantling it for investigation, we find that the pressure ring is cracked and I am sending it herewith for your examination. You will remember some time ago we had a similar occurrence on a Bentley, and it was considered at that time that a probable contributory cause of the breaking was incorrect spacing of the serrations, as the first fracture in that instance was at the root of one of the serrations. In this case you will see that the serrations have been ground in accordance with the latest practice and that the fracture has occurred in the middle of one of the serrations. Mx{John H Maddocks - Chief Proving Officer} | ||