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 a supplier discussing the cobalt percentage in speedometer magnets and the development of self-winding clocks.
| Identifier | ExFiles\Box 62\2\ scan0223 | |
| Date | 26th July 1933 | |
| 105 86135 CONTRACTORS TO ADMIRALTY, WAR OFFICE & AIR MINISTRY BY APPOINTMENT TO HIS MAJESTY THE KING ENGINEERING AND ALLIED EMPLOYERS NATIONAL FEDERATION 1896 TELEPHONE: GLADSTONE 3333 (10 LINES) TELEGRAMS: SPEEDOFAC. PHONE. LONDON. SMITH'S MP REGISTERED TRADE MARK CABLES: SPEEDOFAC, LONDON. CODES: MARCONI.COMMERCIAL.BENTLEY'S. S.Smith & Sons (Motor Accessories) Ltd BRANCHES AT PARIS MILAN SYDNEY WELLINGTON AGENCIES AND SERVICE STATIONS THROUGHOUT THE BRITISH EMPIRE AND IN ALL THE PRINCIPAL COUNTRIES SHOWROOMS & DEPOTS 179-185 GT PORTLAND ST LONDON, W.I. 26-33, COX ST LIVERY ST BIRMINGHAM 14A JACKSONS ROW DEANSGATE MANCHESTER 21, DRURY STREET GLASGOW. C.2. DUBLIN & BELFAST CRICKLEWOOD WORKS LONDON, N.W.2 Please quote our reference: E.1.POD. 26th. July. 1933. WST Messrs. Rolls-Royce Ltd., Derby. Dear Sirs: For the attention of Mr. West. Referring to Mr. Manwaring's call on the 18th inst. The magnet used in our Nemag speedometer is 15% cobalt and we have every confidence as to its permanence. We are, however, prepared to use magnets of 35% cobalt if after experiments we find we get better results therefrom. In these circumstances we are quite prepared to guarantee permanence of any magnets we should use for your instruments. Owing to the slow speed at which the instruments run on Rolls-Royce cars we would not consider it necessary to adopt a ball bearing. The standard speed of a Nemag is approx. twice as fast as would be obtained on a Rolls-Royce car and as we do not have any trouble at all with regard to the fast speed we are naturally confident of complete satisfaction at slow speeds. We are forwarding to you a Nemag speedometer arranged to run at 800 also a Nemag rev. indicator and clock arranged for the Bentley car. We note that you have requested an electric clock to be fitted to the Bentley rev. clock. We are investigating this matter but at the same time we should like to know if you would be interested in a self-winding clock with which we are making experiments. This clock winds by the movement of the car and has a reserve running of one week. In other words, if the car cont. | ||