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).
Clarifying the marking and designation system for sparking plugs from Lodge Plugs Ltd.
| Identifier | ExFiles\Box 162\6\ img094 | |
| Date | 9th December 1925 | |
| By from Wd.{Mr Wood/Mr Whitehead} c.to Hs.{Lord Ernest Hives - Chair} c.to Hm.{Capt. W. Hallam - Head Repairs} c.to Mx.{John H Maddocks - Chief Proving Officer} c.to EWT.(Test Dept). c.to BP. c.to My. c.to D/BP. c.to My/Mt. c.to Ms. c.to CO/AW. Y4425 Wd{Mr Wood/Mr Whitehead}1/NJ9.12.25. Lodge Plugs Ltd. Some months ago a representative of the above-mentioned firm called here and explained the manner in which they were then lettering and numbering their sparking plugs. At that time we were using as standard their C. plug and we had occasion to point out to the Lodge Co. that said plug was known to us as C.65, as on one flat of the hexagon the letter C. appeared and on another flat the figures 65. Their representative explained that the figures 65 had no reference to the design of the plug, but were used to fix the date of manufacture. We understood their representative to say that if a letter and figures were used to identify the particular type of plug, said letter and figures would all appear on one flat of the hexagon. We are now using the C.200 plug and last week my attention was drawn to the fact that some of the plugs just received have the letter C. along on one flat of the hexagon and the figures 200 on the flat on the opposite side of the hexagon. As this hardly agreed with what the Lodge Co's representative told us, we wrote drawing their attention to it, pointing out that as we particularly desire at any time to be able to identify a particular plug, we should be glad if they would let us know whether it is their intention that a C.200 plug should be marked in the way described, i.e., with the C. on one flat and the figures 200 on the flat of the opposite side of the hexagon. We are now in receipt of their reply expressing regret that there should have been any misunderstanding with regard to the designation of their model C. type plugs and adding that in order to prevent any confusion, they are arranging to omit the figures after the letter and in future their steatite plugs will be stamped "Model C", this applying to both their detachable and non-detachable models. They ask that in future when referring to these plugs we will designate them as Model C. Non-detachable (old designation C.65) and Model C. Detachable (old designation C.200). They again explain that in addition to the letter C. on the hexagon of the plug, they also stamp 1/16" figures, which are their own reference as to date of manufacture and have nothing to do with the designation of the plug. (contd) | ||