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 H.M. Hobson Ltd. regarding the supply and calibration of gauge dials and pipe unions.
| Identifier | ExFiles\Box 61\3\ scan0268 | |
| Date | 23th October 1931 | |
| Y4038. CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, AIR MINISTRY AND TO THE DOMINION & FOREIGN GOVERNMENTS. PLEASE ADDRESS ALL COMMUNICATIONS TO THE FIRM, NOT TO INDIVIDUALS. TELEPHONE: SHEPHERDS BUSH 3321. (4 LINES) TELEGRAMS: "ASSEMBLAGE, LONDON" MANUFACTURERS OF Hobson Motor Accessories. Claudel-Hobson Carburetters. Hobson-Perfect Window Regulators. Hobson K-S Petrol Telegages. Hobson Sparking Plugs. WORKS - LONDON AND WOLVERHAMPTON. H.M. HOBSON, LTD. (ESTABLISHED 1903) 47-55, THE VALE, ACTON, LONDON, W. 3. ENCLO. 1. OUR REF. TPS/MW YOUR REF. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/AD. 23rd October 1931. Messrs. Rolls-Royce, Ltd., Derby. Dear Sirs, We beg to thank you for your letter of the 20th inst., and as requested we are sending you under separate cover, three new dials for the gauges in question, written in accordance with the particulars on sheet attached to your letter. The markings will probably be found not to be absolutely accurate by this method of calibration, and we know that you realise the importance of letting us have a tank for actual calibration at some future date, as we have found it more satisfactory to calibrate tanks for levels, rather than fill up the tank and mark off the gauge to suit. Small inaccuracies creep in, caused by the varying size of the meniscus bubble underneath the bell, when employing this latter method for marking off the gauge. With regard to the unions of the connecting pipes on the tank unit and instrument head, we think that the enclosed blue-print will fully explain our practice and the arrangement of the old style tank unit, in relation to the instrument head, and the present one, by which you will see that we have retained the features which were incorporated from the commencement; the object being that the air line assemblies can be withdrawn from store in either direction on the chassis, and connections for the air line and pressure balance line automatically made without the possibility of confusion, or tracing the pipe line through the armour, owing [Side Logos] THE SOCIETY OF MOTOR MANUFACTURERS & TRADERS LTD THE SOCIETY OF BRITISH AIRCRAFT CONSTRUCTORS LTD BRITISH & COLONIAL AEROPLANE CO LTD FILTON BRISTOL INCORPORATED [Sticker on bottom left] MOTOR EXHIBITION CARS & BOATS Oct. 15-24 1931 OLYMPIA OUR STAND No. 407 Gallery FOR-NATIONAL-SCHEME-MEN-DISABLED | ||