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).
Letter to Hoffmann Manufacturing Co. Ltd. discussing criticisms of their equivalent wheel bearing compared to a New Departure bearing.
| Identifier | ExFiles\Box 114\1\ scan0231 | |
| Date | 20th July 1939 | |
| 1015 ? Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}5/MH.{M. Huckerby} 20th. July, 1939. The Hoffmann Manufacturing Co. Ltd., Chelmsford, ESSEX. Your Ref: EL/MES.113571A. Dear Sirs, We thank you for your letter concerning Hoffmann's equivalent of the New Departure No.88128 wheel bearing. There are one or two criticisms which we should like to raise. Firstly, the Hoffmann bearing has nine 7/16 balls whereas the N.D. bearing has nine 1/2" balls, which latter obviously provides a greater capacity. As the New Departure bearing is on almost every American semi-floating axle, the thinner races are not apparently, a disadvantage. Secondly, experiments that we have done here show that the cage of the semi-floating axle wheel bearings is highly stressed when cornering unless the holes in the cages are elongated in the manner we have discussed with Mr. C.H. Smith. New Departure's get over this trouble by a cage strong enough to resist fracture. We are wondering whether the yellow metal cage would do this. We should like to have your views on this letter, particularly as to whether you are willing to copy more exactly the New Departure bearing or whether your N.2943 is already in production. As soon as we hear from you we can discuss obtaining sample bearings for test purposes. Yours faithfully, for ROLLS-ROYCE LTD. | ||