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).
Steering gear preload measurements and recommendations for 25 HP and Phantom III models due to complaints of wandering and backlash.
| Identifier | ExFiles\Box 106\3\ scan0393 | |
| Date | 10th August 1936 | |
| x550 To a.{Mr Adams} to Wor.{Arthur Wormald - General Works Manager} b. to By.{R.W. Bailey - Chief Engineer} c. to Slt. d.{John DeLooze - Company Secretary} to Hx. e.{Mr Elliott - Chief Engineer} to Da.{Bernard Day - Chassis Design} Ha/FJH.{Fred J. Hardy - Chief Dev. Engineer}4/JM.{Mr Morley}10.8.36. 25 HP. and Phantom III Steering. Owing to complaints of wandering and backlash on production 25/30 HP. steering we have been measuring the preloads of a number of Ph.III and 25/30 steering gears before they were fitted to chassis. The attached table No.1 shows the results of these measurements. As can be seen, the loads vary over a very wide range and the proportion due to the cam bearings is also very elastic. Our experience on both Ph.III and 25/30 is that a total preload on the steering gear in excess of 3 lbs. leads to wandering. For the purpose of reducing joggle and preventing backlash developing it is desirable to have the preload as high as possible. Hence it is necessary to compromise. Our previous recommendation of a total of 1½ - 1¾ lbs. still stands. The preloads shown in the attached table No.1 will undoubtedly decrease during the amount of running the gears receive in the test dept. but we do not think that gears originally assembled with more than 3 lbs.load will have fallen to 1¾ lbs. by the time they reach customers. We therefore recommend that the test dept. should check the amount of preload before finally passing off cars. At the same time we consider that more care should be experienced during assembly to obtain the specified amount of preload. | ||