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).
Practice and implications of screwing drain plugs directly into an aluminium base.
| Identifier | ExFiles\Box 14\1\ Scan018 | |
| Date | 1st August 1930 | |
| X7000 By.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} Hs.{Lord Ernest Hives - Chair} E1/1426.8.30. X.7000 X.7190. OIL SUMP AND FILTER SLUDGE DRAIN PLUGS SCREWED DIRECT INTO ALUMINIUM. It is not desired to unduly prolong the correspondence with regard to this question but the contents of your memo. By8/G22.8.30 are most surprising. We know of one instance in particular when a steel drain plug of large diameter with fibre washer is used direct in the aluminium base with perfect satisfaction on a car which has been produced in thousands. It is also a fact that all RR. chassis and aero engines up to L.H. P.2 have had drain plugs screwed direct in the aluminium, and we have never heard of any trouble in connection with this practice. We would suggest that the duralumin main bearing cap thread is a special case in which excessive temperature, stress, vibration, and the effect of the oil feed pipe hanging on the screw supply a different set of conditions. If you suspect that the difference in expansion may give rise to trouble both plugs could be in bronze, to avoid having to use the inserts with additional parts for locking. E.{Mr Elliott - Chief Engineer} | ||