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 The S.U. Company Ltd. regarding dimensional limits to reduce slack in a pump armature and roller assembly.
| Identifier | ExFiles\Box 149\6\ scan0032 | |
| Date | 18th September 1937 | |
| 1263 Experimental Dept. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}1/JH. 18th September, 1937. The S.U. Company Ltd., Bordesley Green, Adderley Park, BIRMINGHAM. For the attention of Mr.Leslie Kent. Dear Sirs, We have come to the conclusion that to prevent side thrust and wear on the rollers in the S.U.pump it will be necessary to reduce the slack in the armature and roller assembly. Working to your drawings with the best possible and worst possible combination of limits and with rollers .429 to .430. The total slack is as follows. Best limits. Roller size. Pot 1.999" .429" .430" Armature 1.138" Difference .861" .003" .001" Total slack. Worst limits. Pot 2.001" Armature 1.136" Difference .865" .007" .005" Total slack. The effect of slack in the assembled unit will cause twice the side thrust for an equal amount of eccentricity in the pole piece added to which the side thrust from both causes is cumulative. It would not be possible to use a roller .431" in dia. in the case of the bestpossible combination of limits and we realise the difficulty of working to finer limits all round. | ||