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).
Comparison between a pressed steel sump and a die-cast aluminum sump for the Phoenix model.
| Identifier | ExFiles\Box 111\2\ scan0238 | |
| Date | 1st September 1937 | |
| [Handwritten text] file Edwards 1044 800 Can you make the wols agree with Vauxhall figures Rm{William Robotham - Chief Engineer} [Typed text] To Rm.{William Robotham - Chief Engineer} from RHC{R. H. Coverley - Production Engineer}/SB.{Mr Bull/Mr Bannister} c.c. to RY. c.c. to Hs.{Lord Ernest Hives - Chair} REC/SB.{Mr Bull/Mr Bannister}1/LS.1.9.37. In reply to Rm.{William Robotham - Chief Engineer}4/HF.{H. W. Frost - Coachwork Inspector}21.8.37. concerning the proposal to adopt a pressed steel sump on Phoenix, we have made investigations and find that this design generally seems to give reasonable satisfaction on service, but we do not consider the results would be equal to those obtained with a die cast alum sump. The sheet metal type we consider would be more prone to distortion in service, and requires core packings about .075 thick to accommodate surface in-accuracies. The Vauxhall type of sump with exposed front and rear bearing caps has four separate cork packings, and should a small portion be broken from one of these during assembly or the ends not butt, a serious oil leak would result, although Oscrofts have not suffered from this trouble on the Vauxhall cars up to the present. As you will appreciate the leak from a thick cork packing which had broken away would be much more serious than with a .005 thick vellumoid washer. The cost of casting dies would be about £150.0.0d. as compared with £300.0.0d. for press tools, these figures being based on the assumption that the design would be simple and of appropriate form for the method of production in each case. The die cast sump would require very little machining and the principal increase in cost over the pressed sump would be due to material whilst the relative weights should be about the same (assuming an 18.SWG. steel sump and a 150 section alum casting.) A further point in favour of the cast sump is that it could be produced in our own foundry, whereas our largest existing press is not sufficiently heavy for the sheet metal sump, hence we should be in the hands of outside suppliers with consequent high cost, risk of bad work, etc., We therefore consider that aluminium sump would give greater satisfaction than a pressed steel one provided that design is definitely suitable for die casting. RHC{R. H. Coverley - Production Engineer}/S.Bannister. | ||