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).
The methods of production and fitting for crankchambers, brasses, and bearings, emphasizing interchangeability and repair standards.
| Identifier | Morton\M2.1\ img016 | |
| Date | 4th January 1918 | |
| -2- Re - Methods of Production. AERO filed on the outside. This cannot be necessary or desirable, and I should be glad to hear whether this is true, and if it is true, who is the author of it. My impression is that the correct way of fitting these brasses is to bore out the crankchamber as accurately as possible so as to leave a minimum of work for the hand scraper. This is a fine job of machining and should be paid for in proportion to the accuracy obtained as lately suggested by yourself and Mr. Moon. The crankchamber should then be scraped to the standard bar and the liners and caps also fitted to the standard bar. The bearings should be produced in quantity and finished (independent of the crankchamber) on the outside by grinding to the standard of the bar plus a small positive tolerance limit. The brasses would then either just fit their housings or collapse slightly in being pressed in. If the bearings are well produced they should be practically interchangeable and should require no scraping to the crankshaft. It has been suggested, however, that the white metal bearings should be re-bored by a single pointed tool, but I fear that considerable care would have to be taken in arranging this operation for it to be really worth the time and inconvenience. In conclusion I must emphasize the great desirability of the small tool equipment being to a very high standard of perfection and the machining operations carried out so as to require the most perfect interchangeability and the minimum of hand fitting and I quite agree that all repairs should be done wherever possible by scrapping the defective part and re-assembling the engine with new pieces instead of any attempt at re-lining old brasses or patch up worn pieces or making odd sized pieces to suit worn parts. | ||