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).
Cost analysis estimating savings on 25/30 and Bentley engine components by changing production to die casting.
| Identifier | ExFiles\Box 142\4\ scan0040 | |
| Date | 23th November 1936 | |
| -2- Rm{William Robotham - Chief Engineer}/Smth4/R.23.11.36. (a) 7 1/2% on foundry labour and charges. (b) 10% on machining labour, and charges owing to smaller machining allowance, and good finish of non-machined surfaces. (c) 25% on material owing to the use of thinner sections and the fact that the runners and risers can be melted up again with the original alloy. We estimate that £10 could be saved on the 25/30 engine. Taking the cost of the dies as:- for crankcase top half 750 " lower 300 " clutch pit ....... 250 " gear box ......... 450 " rocker cover ..... 150 " wheel case ....... 150 Total £ 2050 The die cost per engine would be:- distributed over 500 units £4/2/- " " 1000 " £2/1/- " " 2000 " £1/-/6. No allowance for reduced tool maintenance. We are making 30 25/30 and Bentley engines a week. Spreading the die cost over two years' output, and using the cheaper alloy, we estimate that we could save £12/16/- per unit by changing to die casting. Minor design modifications would be necessary to some of the castings to enable this to be done. Rm{William Robotham - Chief Engineer}/Smth. | ||