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).
Use and modification of Thompson Steering Tube Joints on various car ranges.
| Identifier | ExFiles\Box 153\4\ scan0011 | |
| Date | 28th December 1939 | |
| SECRET. To Rm.{William Robotham - Chief Engineer} from Ev.{Ivan Evernden - coachwork} c. to Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} c. to Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} 1300 re Thompson Steering Tube Joints. From the point of view of stress in the ball neck we need the larger Thompson Joint on all cars in the Senior Range. On the sketch attached we shew the clearances of this joint on the front end of the side steering tube and the front pan. The distance between the ball centre (the tube centre) and the lever face on this joint is increased by .280 ins. This raises the position of the front end of the side steering tube which does not appear to matter. On both straight and bent front pan suspensions the cross steering tubes are in difficulty due to this changed dimension since the shape of the window in the torque arm is at a maximum and the bottom of the torque arm at the window cannot be lowered due to ground clearance. Therefore for both straight and bent front pan cars this joint demands side and centre levers with modified sets in the arms to maintain exactly the existing positions of the cross steering tubes. Are we able to make such a change for Ripplet 2.R.2.? We would also like to point out that the clearance between the ball end and the tyre will be reduced by .125 ins. At the moment we have .750 in. dia. cross steering tubes and the joints are for .875 tube. We should have to ask that these joints be made to suit our size of tube if we did not wish to reduce the already fine clearances at the torque arm window. Likewise we cannot have a clamp adjustment at the wheel end of the cross steering tubes for similar reasons. We presume the makers would arrange this. | ||