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).
Properties and application of various lubrication oils and greases, focusing on mineral versus compound oils and their effects on ball bearings.
| Identifier | ExFiles\Box 32\4\ Scan272 | |
| Date | 12th September 1927 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. HL. BY.{R.W. Bailey - Chief Engineer} X1588 c R1/M9.12.27. LUBRICATION OILS. X.1588 X.544 X.967 You will remember that I have always been in favour of oils rather than more or less stiff grease, the reason being that the grease gets rubbed off and does not readily come back to the surface by capillary attraction, etc. You will also remember that I have been in favour of compound oils instead of straight minerals, and now it appears that this requires a certain amount of modification, the reason being that although a judicious compound is a better lubricator than the straight mineral, there is a defect of want of stability in nearly all animal, vegetable, and fish oils. I shall be glad if HL. will study this matter for the guidance of our recommendations to chassis and aero engine users. My fear is that all these compound oils, will, when standing, generate acid, and corrode the steel work, especially such things as ball bearings, and it is advisable for us to use great caution in the storage of engines and chassis when lubricating with compound oils. There is also another point on which I require some information, and that is, are there two types of mineral oil obtained from petroleum, shale, and other sources? Somewhere I have read that oils from certain sources have an asphaltum basis, whereas oils from other sources have a paraffin basis, and I assume that the residues of distillation are of the nature of asphaltum, and paraffin wax relatively. If this is so I would like to know whether there is any distinct difference in their lubricating qualities. The impression I have is that from a lubricating point of view the mineral oils with a paraffin base are quite satisfactory, and as a specimen we have Price's Amber gear oil, whereas those from an asphaltum basis are extreme-ly unsatisfactory, being very poor in lubricating qualities. 2.. On the other hand I believe the pure mineral oil from the paraffin basis sets at a temperature frequently met with in England in winter, whereas the oils from an asphaltum basis do not set, the result being that many of the oil makers blend the two oils or supply oil of the asphaltum basis when a low setting point is demanded. In conclusion it will be observed that we ought to know more about the aforegoing, and there appears to be evidence and an opinion, that it is better to pack ball bearings with vaseline so as to avoid the change of being oiled with lubricating oils containing, or likely to contain, acids. Mr. Bentley of Royce Ltd. is getting me an opinion from the ball bearing people on this subject. In the meantime I cannot imagine it is altogether satisfactory to build machinery so that it is impossible to oil the ball bearings after the first grease packing. We find it however the practice of the latest contd :- | ||