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).
Letter to Adamant Engineering Co. Ltd. regarding faults and eccentricity found in supplied cams, detailing tests and suggesting corrective actions.
| Identifier | ExFiles\Box 153\2\ scan0207 | |
| Date | 12th December 1936 | |
| - 2 - 12th. December 1936. Messrs. Adamant Engineering Co.Ltd., LUTON. spigots at each end, it is necessary to ensure that the cam or blank is running concentrically with the spigots in question. Since our visit we have had a further eight cams rejected, and in every case they are in the same condition as the one described under heading (b), and there can be no question that our major troubles are due to the fact that this condition obtains in quite a large percentage of the cams delivered. If the eccentricities lay on a single axis correction would be simple, but it is impossible for us to do anything owing to the fact that the eccentricities at each end are removed from each other by such a large angular displacement. The Experimental Department made a set up by which a fulcrum for the arm was formed on the same centre as that from which the cam was originally generated. A ball was secured to the end of the swinging arm, so that it could be set up closely into mesh, the cam was then rotated and this again indicated clearly eccentricities of the type described in my earlier paragraph, with an angular displacement in this particular worm between the two ends of approximately 120°. We feel that unless you make a serious attempt to follow out the scheme we have again indicated above there is little hope of obtaining worms which are regularly alike, and this is all that we really require, as whilst we agree there is an interference if the worm is true, this interference can easily be overcome by eccentric grinding of the roller bearing races, but obviously this is not possible unless the cam is first produced in such a manner as to give similar final results in each case, in other words we are satisfied that the faults are not due to quenching but due to inaccurate setting up from operation to operation. Yours faithfully, FOR ROLLS-ROYCE LIMITED. TECHNICAL PRODUCTION ENGINEER. | ||