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).
Casting specifications and experiments for brake drums with cast-in backplates.
| Identifier | ExFiles\Box 120\1\ scan0283 | |
| Date | 12th February 1940 | |
| 1028 W/G To Vs.{J. Vickers} Copy to Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}13/ML.12.2.40. Brake Drums with Cast-in Backplates. We thank you for your Memo. Vs.{J. Vickers}2/ST of the 6th. inst. We will instruct some drums with thinner backplates, but will probably content ourselves with one dozen, from which we should obtain 2 sets of 4. The last drums you made for us were cast to finished dimensions on the outside, including the two ribs. Will you please let us know to what limits the various diameters could be cast on a production basis. We ask this question because the finished thickness at the base of the ribs is only 0.200. We obviously cannot allow a large minus limit on this for reasons of strength and heat transfer. On the other hand we do not desire a large plus limit as this adds considerably to the weight. We would like to specify limits of plus or minus 0.025 on the diameter. We are interested by your remarks about pressing backplates out of shape before casting so that they are correct when cast in. We should be glad if you could send us a report on your experiments on this subject, giving the amount and direction of the deviation from the true shape of the backplate. Do you recommend that the thin backplates we propose to instruct should have the same deviations as you found desirable on the previous backplates? Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} | ||