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).
Failure of axle pinion ball bearing cages, proposing alternative materials and heat treatments.
| Identifier | ExFiles\Box 84\4\ scan0383 | |
| Date | 29th April 1938 | |
| Da.{Bernard Day - Chassis Design} Rm.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}/RH.{R. Hollingworth} Hs{Lord Ernest Hives - Chair}/Hdy.{William Hardy} HPS{Horace Percy Smith - Experimental Factory Mgr} Ds/TMD. BY/OBL. BENTLEY. RE: AXLE PINION - BALL BEARING CARRYING COMBINED JOURNAL AND THRUST. Referring to the trouble we have had with the cages on the above bearings breaking up under certain conditions of running, I have been under the impression all along that the cages in question were heat treated Stainless steel. I now discover they are fully annealed ball bearing steel, which has a composition of 1% chromium and 1% carbon. This steel in my opinion in this condition is quite unsuitable for this purpose. I think that the only way to overcome the trouble is to increase the tensile strength of the material, so that it has the highest resilient elasticity possible, and I would therefore suggest that we make some of these cages, say half a dozen, in silico chromium steel and heat treat them in practically their fully machined condition, leaving only the necessary grinding allowance on the bore of the spigot. The brinell aimed at should be 369 to 402. If we have a difficulty in getting plain silico chromium steel we could produce the cages in S/ZNCR. which would be quenched out and given a heat treatment at 140°C for one hour to release the stresses. This again would be heat treated in the final condition, with the exception of the grinding allowance. This matter is urgent, and I would like a drawing issued as quickly as possible, covering both of these proposals, i.e. 6 in silico chrome spring steel and 6 in S/ZNCR. BY.{R.W. Bailey - Chief Engineer} | ||