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).
Report to Ariel Motors Ltd. on a modified bearing alloy, its composition, and application guidance.
| Identifier | ExFiles\Box 115\5\ scan0010 | |
| Date | 16th March 1938 guessed | |
| 1. Messrs. Ariel Motors Ltd. There is, in addition to the foregoing, a modified form of AC.7, which it will be noted eliminates Magnesium and Antimony contents, and the Copper content is slightly increased with a view to producing the material having a Brinell hardness between 48 and 65, which according to tests carried out shows that it will run very well in conjunction with soft shafts and testing has been carried out against Nickel-Chrome Steel of about 280 Brinell. The composition of this alloy is as follows - Tin ............ 5.3 to 6.6% Magnesium ...... 0.7 to 1.0% Nickel ......... 1.5 to 1.8% Copper ......... 0.6 to 0.9% Silicon ........ .2 to .4% Iron ........... .2 to .4% Further this material is suitable for cold bending or reducing and therefore suitable for certain types of bearings produces from strip. This latter aspect, however, would not affect your proposition, which would be the casting and machining of shells to fit into the existing connecting rods. With reference to the various other points which have vital bearing on a satisfactory performance, we quote as follows from technical data supplied by Messrs. Rolls Royce Ltd., and believe that this will be a further guide to you for the successful application of this type of bearing. LUBRICATION. "We have found that lubrication plays a tremendously important part in successful bearing operation, and too great a care cannot be taken in establishing a sufficient oil supply, this particularly applies to bearings for use in high speed high performance engines, where explosion and inertia loads can be very high. INTERFERENCE FIT. We recommend that bearings are fitted with their outside diameter greater than the diameter of the housing into which it fits. The figure we usually work to is 0.0005/inch diameter. NIP OF BEARINGS IN HOUSING. By nip of bearing, we mean the amount by which the | ||