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 Borg & Beck Ltd. concerning the 'out of roundness' of clutch covers and its impact on flywheel assembly balance.
| Identifier | ExFiles\Box 129\3\ scan0190 | |
| Date | 8th April 1936 | |
| Exptl. Dept. Hs{Lord Ernest Hives - Chair}/Smth.16/KW. 8th April, 1936. Messrs. Borg & Beck Ltd., Tachbrook Road, Leamington Spa. For the attention of Mr. Barker. Dear Sirs, Confirming the visit of Mr. Scott and the writer to your Works yesterday, we discussed several points in connection with the finish of the production 10" & 11" clutches. Of these we consider the out of roundness of the outer diameter as being by far the most serious, affecting as it does the limits to which we can hope to balance the flywheel assembly. You will appreciate that when we asked for the outer edge of the cover to be machined to a limit of .002", and you agreed to do this, we were of course only concerned with the finished product. We agree that on the unassembled covers you showed us yesterday the outer diameter was true within the limits asked for, but if distortion takes place after assembly the whole purpose of the special method is invalidated. For instance, on the 11" clutch, an eccentricity of only .001" causes an out of balance of 2/5 oz/in., which is practically the limit of out of balance to which we are trying to work. We feel that this problem should have been anticipated before you agreed to the special method of locating and fixing the clutches on to the flywheel. | ||