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).
The likely standardisation of the smaller 14 mm sparking plug.
| Identifier | ExFiles\Box 58\1\ Scan172 | |
| Date | 23th October 1931 | |
| Y5970 To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to Rg.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} Da.{Bernard Day - Chassis Design} SPARKING PLUGS. Hs.{Lord Ernest Hives - Chair}5/MJ.23.10.31. X.4425. X.1918. X.5970. X.7970. It appears to be coming definitely established that the smaller size of sparking plug is likely to be standardised. The sparking plug people say that they can make a plug with a 14 mm. thread equal to the present standard plug with 18 mm. thread. There are, of course, plugs made with 12 mm. but in their opinion this is on the small side for a general purpose detachable plug. We understand that the 'Nash' car people and the 'Chrysler', are making some of their models fitted with 14 mm. plugs. Most of the motor-cycle people have standardised a 14 mm. plug. It should therefore be only a question of a short time before supplies of these plugs are available in all countries. We are sending to E.{Mr Elliott - Chief Engineer} samples of plugs. Hs.{Lord Ernest Hives - Chair} | ||