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).
Examination report on the poor finish of a Marles-Weller 20-EX steering component, suggesting alternative manufacturing methods.
| Identifier | ExFiles\Box 28\2\ Scan216 | |
| Date | 6th July 1933 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from RHC.{R. H. Coverley - Production Engineer} X4094. RHC.{R. H. Coverley - Production Engineer}4/BE6.7.33. Marles-Weller Steering - 20-EX The Marles-Weller Steering has been examined; the fulcrum pin and spherical pads are a poor finish, and cracked as shewn on attached sketch. Finish of steering worm is very poor. This is a square thread, and grinding is impossible on account of grinding wheel interference, and has apparently been produced by first gashing on the centre lathe, and finished by milling with the cutter set radial to the axis of the worm, which, no doubt, accounts for the very rough and chattered finish. The undercut which is at the bottom of the thread, has obviously been cut on the centre lathe, to provide clearance for the milling cutter. It is difficult to understand why this method was adopted, as a much superior finish could be obtained by finishing on the centre lathe, which would give a more accurately formed thread, one side of the thread is square, the other being an inverted angle of 1° or .007". We are arranging to send this Steering into the Stores for despatch. RHC.{R. H. Coverley - Production Engineer} | ||