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 regarding backlash issues in carburetter mixture controls.
| Identifier | ExFiles\Box 31\5\ Scan083 | |
| Date | 22th July 1933 | |
| X1051 Hs{Lord Ernest Hives - Chair}/Rem.3/KT. July 22nd 1933. The S.U. Company, Adderley Park, B'ham. Dear Sirs, We have been very disappointed with the amount of backlash in the mixture controls of the S.U. carburetters. You have supplied us with a sketch showing modifications in design to overcome this trouble but we think the fault is almost entirely a matter of material and workmanship. Measurements of parts taken off new carburetters shew that whilst the holes in links and levers are of consistent size, the pins vary considerably and appear to be responsible for most of the slackness complained of. Apparently these pins are S/M.{Mr Moon / Mr Moore} hardened by the Scintilla or similar process after being turned to size. Development of wear in the holes would be less rapid if the initial clearances were more carefully watched, the use of S/ZN pins hardened and ground to size in accordance with RR. practice being recommended. The size of pins and holes should be within the limits specified below :- Pins .187 -t diameter. Holes .187 plus ¼ diameter. We should be pleased if you would go into the matter and see if you are in agreement with our views. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||