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).
Production cost savings by using softer cranks, detailing heat treatment and machining processes.
| Identifier | ExFiles\Box 132\2\ scan0225 | |
| Date | 8th September 1941 | |
| -2- (6) Reasons for production saving in cost if we use softer cranks :- It could be heat treated as a forging, and machining would be continuous. With 320 Brinell crank, rough machining only is carried out prior to heat treatment, and the subsequent correction for bending, bowing, angularity etc. has to be done before completing the machining operations. Labour saving would be 10 - 15% on total factory cost. (7) We attach no importance to any tests carried out to date by the exptl. Dept. because the method does not assimilate anything like the conditions in which we are interested for this particular experiment. Conclusion. In March 1940 HPS.{Horace Percy Smith - Experimental Factory Mgr} had four rough forgings for chassis cranks. It should be possible to get one of these heat treated to 241 - 269 Brinell, and machined to our drawing RE.2697 so that this experiment can be carried out. To run such a crank with strip bearings would be a useful step towards our post war programme. Is it not possible to have a die produced by English Steel Corp. for the above crank RE.2697 ? which incorporates integral balance weights. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} [Signature] | ||