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).
Appropriate type of Extreme Pressure (E.P.) oil for running-in gearboxes and gears.
| Identifier | ExFiles\Box 145\3\ scan0213 | |
| Date | 31th October 1940 | |
| W/G M/Swdl.{Len H. Swindell} from Rm.{William Robotham - Chief Engineer} rils gen. 1235 Rm.{William Robotham - Chief Engineer}6/ML.31.10.40. With reference to your M/Swdl.{Len H. Swindell}5/BA.28.10.40. I think for running-in, you need the mildest E.P. oil you can use without getting seizure. If you use high E.P. oil the parts will not run in. We proved this on our gearbox when we ran it on extreme pressure oil. It was remarkably good for stopping the gear tooth pitting, but it prevented the syncromesh cones working. The mildest form of E.P. oil that we know is straight mineral oil with 10% lard or sperm. In the same class is pure castor oil. The next stage is Robertson's dope oil and the stage beyond that, Hipress, which is our standard axle oil. Hipress will attack mild steel but not hardened steel. I should certainly agree that to get any successful running-in, gears which are actually to work together should be run-in in pairs. When are you coming down to Derby again? Rm.{William Robotham - Chief Engineer} | ||