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).
Discrepancies in the dimensions of sample spanners compared to their drawings, with suggestions for rectifying the production dies.
| Identifier | ExFiles\Box 20\8\ Scan046 | |
| Date | 19th June 1923 | |
| To BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. to CJ. c. to HS.{Lord Ernest Hives - Chair} c. to EP.{G. Eric Platford - Chief Quality Engineer} X.1027 E1/M19.6.23. SAMPLE SPANNERS TO LeC.1645 X.1027. We agree that the jaws of the sample spanners are no more than .045" larger than correct size in the worst case, but we see no reason why the dies should not be made to size in the first place to avoid this error. Drop forgings always tend to become heavier and heavier as production goes on unless carefully watched. We do not agree with your statement regarding the handles of the spanners. We think the thickness of the web should have been measured as well as the flange, the former being the more important dimension as regards weight. Our measurements of the samples came out as follows :: HANDLE. As drawing. As model. .150 .175 .137 .175 .125 .154 .112 .119 .087 .105 .150 .180 .125 .154 .100 .128 .100 .150 If the smaller panelled spanners can be made to size we see no reason why the larger ones should not be also. It is the excess of web thickness which leads to the conclusion that the dies may have been somewhat overcharged with metal. We should be glad if you would have the samples machined to the drawing sizes if possible on the handles as well as the jaws and returned to us. We suggest that before going into production with the dies as made it might be an easy matter to grind off the faces of the dies the amount that it would be possible to reduce the drop forgings in thickness as we do want these spanners to be as light as possible. We do not think we are asking impossibilities from the drop forger. If we can see no reason why the 1/4", 7/16" and 1/2" should not be made to drawing size. E.{Mr Elliott - Chief Engineer} | ||