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 from AC-Sphinx Sparking Plug Co. Ltd. discussing the design and dimensions of a proposed 14mm shielded spark plug.
| Identifier | ExFiles\Box 163\5\ img032 | |
| Date | 5th June 1936 | |
| TELEGRAMS: SPHINX, DUNSTABLE TELEPHONE: DUNSTABLE 360 PRIVATE BRANCH EXCHANGE. 6011 THE AC-SPHINX SPARKING PLUG Co. LTD. DIRECTORS: N. F.{Mr Friese} STOCKBRIDGE. W. O.{Mr Oldham} KENNINGTON. C. J.{Mr Johnson W.M.} BARTLETT. DUNSTABLE BEDFORDSHIRE OUR REF. NFS/CEB. YOUR REF. 5th June, 1936. Messrs. Rolls-Royce Limited, Derby. For the Attention of Mr. H.{Arthur M. Hanbury - Head Complaints} E.{Mr Elliott - Chief Engineer} West. Dear Mr. West, We have now laid out the proposed 14 mm. sinterkorund shielded type plug (of which we are arranging to make a set of twentyfour for you, as per paragraph (1) of my letter of May 29th last). Our main difficulty lies in the size of the plug hexagon, which we have had to increase to 15/16" across the flats to enable the plug box spanner to clear the enlarged lower end of the sleeving component, which we cannot reduce less than 59/64" diameter. I enclose herewith a blueprint of our layout drawing X408, which will be self-explanatory on this point. Before we proceed with the twentyfour test plugs to this drawing, will you please confirm that the hexagon size of the plug as drawn is not too large, i.e., that the 15/16" box spanner will not foul the side of the plug pocket (if any) in screwing the plug in. Upon receipt of your reply we will proceed immediately, as I am anxious to get these plugs on test without delay. Yours faithfully, N.F. STOCKBRIDGE, Managing Director. Enclosure. MAKERS OF AC SPARKING PLUGS - AC AIR CLEANERS - AC PETROL PUMPS - AC PETROL GAUGES - AC OIL FILTERS - AC OIL GAUGES | ||