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).
Gear clearances, backlash, and tolerances for the Spectre Gearbox, comparing them to Chrysler and American practices.
| Identifier | ExFiles\Box 94\1\ scan0017 | |
| Date | 15th June 1934 | |
| 45644 328 To EYT and RHC{R. H. Coverley - Production Engineer}, from HDY.{William Hardy} c. Hengendyke. HS.{Lord Ernest Hives - Chair} DB.{Donald Bastow - Suspensions} HDY.{William Hardy}3/HP.15.6.34. SpectreCodename for Phantom III Gearbox. With reference to the use of sliding helical gears, Chrysler practice appears to be to selectively fit the gear and shaft to give a diametrical clearance of .0002". It is thought that it would be best to start with an equally close fit for the 1st speed wheel of the SpectreCodename for Phantom III box and experiment later with increased clearances. With regard to the backlash of the gear on the splines, Chrysler instructions are that this is "to be reduced to a minimum by selective assembly". The drawing tolerances on the splines of the shaft are size to .001 and for the broached keyways in the gear size to + .002". American practice is to fit the gear on the tops of the splines and it would appear to be a suitable opportunity to try this method on the 1st speed wheel of the SpectreCodename for Phantom III, and as RHC.{R. H. Coverley - Production Engineer} is in agreement, would you kindly instruct this gear to be mounted in this way. HDY.{William Hardy} | ||