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 inspection and repair of the Spectre I rear axle due to excessive backlash.
| Identifier | ExFiles\Box 92\5\ scan0014 | |
| Date | 6th June 1935 | |
| x302 To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from RHC.{R. H. Coverley - Production Engineer} De. ----------------- RHC.{R. H. Coverley - Production Engineer}21/ETM6.6.35. SPECTRECodename for Phantom III I REAR AXLE. Following upon last reports regarding excessive slack in SpectreCodename for Phantom III I transmission, the rear axle was removed for examination and the backlash checked at various points between the driving flange and the road wheels. A check taken on the assembled axle showed that the total backlash measured through the bevel gears, differential and hubs, amounted to .175 on the bolt centres of the driving flange with an applied torque on 6lbs/ft. Of this .015 was found due to the backlash between the bevel gears, which has increased .004 between the teeth owing to wear in the combined ball and roller pinion bearing G.81150, in which the end play had increased from .0005 to .006 due to wear on the ball track. This bearing was also showing signs of wear on the roller track and is therefore being returned to Hoffmans for examination. The remainder of the backlash is accounted for by excessive wear taking place on the various adjusting washers in the differential, the actual figures being - G.53869 - Axle Shaft Washers - .010. G.54087 - Diff: Washers - .010 - .012. G.54478 - Adjusting Washers - .004. There was also a certain amount of slackness between driving pieces and the axle shafts and hubs. This axle was afterwards reassembled with a new pinion bearing, new adjusting washers taking up all slackness in the differential, and new drivers fitting tightly to the hubs and axle shafts, with which replacements the total backlash at the pinion driving flange came to .025 measured at the bolt centres. RHC.{R. H. Coverley - Production Engineer} [Handwritten note in the left margin] Grey- What are we doing to improve these. | ||