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).
Various designs for spanners to be used on internal hexagon plugs.
| Identifier | WestWitteringFiles\T\January1929-February1929\ Scan160 | |
| Date | 19th February 1929 | |
| FROM E.{Mr Elliott - Chief Engineer} SECRET. E1/M19.2.29. C. to SG.{Arthur F. Sidgreaves - MD} WCR. HS.{Lord Ernest Hives - Chair} EV.{Ivan Evernden - coachwork} re. SPANNERING INTERNAL HEXAGON PLUGS. Referring to the attached minutes of a meeting between SG.{Arthur F. Sidgreaves - MD} CWB. and EV.{Ivan Evernden - coachwork} on the SS.{S. Smith} chassis, item No.(5), we use a number of plugs with internal hexagons for engine work both chassis and aero, but we do not think the suggestion is practical except perhaps for very large plugs. We should agree however that the outside of an ordinary box spanner is not very satisfactory for operating these plugs. One suggestion for improvement might be to make the box spanners of thicker tube and dress them down to the required hexagon on the outside by 3 milling cuts. Another idea is to limit the number of internal hexagons to be used and provide special spanners for same. For example on the Fiat chassis there is one spanner of this sort and it operates 8 or 9 different plugs and caps on the engine, clutch case, gearbox, and back axle. The spanner in this case is made from bar and bent as in sketch. It is very satisfactory. Equally good and simple might be a short straight spanner for operation by one of the standard tommy bars provided. We should say this would be more useful than the Fiat type, and it might be made double ended. With regard to any larger sizes there are some special one ended tubular spanners in the kit which might be made to serve two purposes. E.{Mr Elliott - Chief Engineer} | ||