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).
Modifications to the Wraith steering gear.
| Identifier | ExFiles\Box 9\7\ 07-page022 | |
| Date | 12th January 1937 | |
| SECRET 1044 . 650 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Ev.{Ivan Evernden - coachwork} WRAITH STEERING GEAR. We wish to suggest the following modifications to the Wraith steering gear, in view of experience gained to-date on this and on the 25/30 HP. gear. (1) We consider that the ball bearings of the roller follower as originally designed are inadequate for the loads they will have to carry. Alternatively, we suggest the roller follower as designed by Ransome & Marles and shewn on the attached print Rm.{William Robotham - Chief Engineer} 294 with 11-19/64.dia. balls in each row. This roller has an assembled width 0.100 greater than the present arrangement so that it will be necessary to increase the opening between the jaws of the rockershaft by this amount. There is ample clearance to move out the head of the bolt by 0.075" if necessary. (2) The original scheme does not show any packing washers between the inner races of the roller follower and the rockershaft jaws, whereas these will be necessary. Messrs Ransome & Marles can supply the inner races to 1.257 ± 0.003, and we suggest that we should machine the rockershaft to 1.262 + 5., and make up the difference of 0.002 - 0.013 by a pack of 0.002 and 0.003 shims, 1.062 dia. The inner faces of the rockershaft jaws should be spotfaced to a diameter sufficient to allow the shims and inner races to be slipped in from the open side. (3) The rockershafts produced experimentally have a considerable amount of excess material on the external surface between the two bearings, as shewn to Da.{Bernard Day - Chassis Design} and Ev.{Ivan Evernden - coachwork}, owing to insufficient detail on either the scheme or detail drawings. (4) We suggest that the tab for knocking round the eccentric adjusting sleeve should project downwards instead of upwards to make it less obvious to Owners that this is an adjustment. If the Design Dept. are in agreement with the above, will they please issue the necessary drawings. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} | ||