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 the superiority of hourglass steering worms for the Phantom 111.
| Identifier | ExFiles\Box 95\1\ scan0459 | |
| Date | 30th November 1937 | |
| To BY.{R.W. Bailey - Chief Engineer} & Rm.{William Robotham - Chief Engineer} From RHC.{R. H. Coverley - Production Engineer} c. to Hs.{Lord Ernest Hives - Chair} 358 RHC.{R. H. Coverley - Production Engineer}9/MJ.30.11.37. F.J. HARDY PHANTOM 111 HOURGLASS STEERING WORMS. J/H Investigations carried out on the Phantom 111 Hourglass Steering Worms produced by the Fellows Machine Tool Co. have proved the superiority of worms produced by the 16 tooth generating cutter as compared with the one produced by a 17 tooth cutter and the present production worm as supplied by the Adamant Engineering Co. The position of minimum backlash extends over a larger interval of steering movement with a considerable reduction of backlash at the extreme position of steering lock. This decreased backlash will eliminate any complaint of excess steering wheel movement when the car is standing with the wheels in either 'locked' position. We have attached herewith a graph shewing the relative amount of backlash on the different types of worms as these are rotated away from the centre position of contact and illustrates the superiority of the 16 tooth generated type worm. The tests carried out with the 17 tooth generated type worm shews this to be similar in operation to the Adamant product but shews slight surface unevenness which could be eliminated by increasing the machine strokes during the revolution of generation. The production of the worm produced with a 16 tooth generated cutter will not present any additional manufacturing difficulties and it is therefore recommended this should be adopted. RHC.{R. H. Coverley - Production Engineer} Since dictating the above we have received Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}2/AP.29.11.37 which clears the position, but as this report was written we think it advisable to circulate. | ||