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 S. Smith & Sons regarding criticism of their Jackall Jack System fitted to a test car.
| Identifier | ExFiles\Box 26\3\ Scan340 | |
| Date | 30th December 1933 | |
| 105 X 3117 File CONTRACTORS TO ADMIRALTY, WAR OFFICE & AIR MINISTRY S.Smith & Sons (Motor Accessories) Ltd CRICKLEWOOD WORKS LONDON, N.W.2 TELEPHONE GLADSTONE 3333 (10 LINES) TELEGRAMS: SPEEDOFAC, PHONE, LONDON. CABLES: SPEEDOFAC, LONDON. CODES: MARCONI, COMMERCIAL, BENTLEY'S. BY APPOINTMENT TO HIS MAJESTY THE KING 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.1. 26-28, COX ST & LIVERY ST BIRMINGHAM 14, JACKSONS ROW DEANSGATE MANCHESTER 21 DRURY STREET GLASGOW, C.2 DUBLIN & BELFAST Please quote our reference: E.6 FGE/MM. Your Ref: Hs{Lord Ernest Hives - Chair}/Bwg.{J. C. Bowring}3/KW. December 30th. 1933. Messrs. Rolls Royce, Ltd., DERBY. Dear Sirs, We beg to thank you for your letter of the 28th inst, and note your criticism of the Jackall Jack System fitted to your test car. Jacking up a car of that weight on a 1 in 7 gradient imposes a sideways pull on the jacks of about 7 1/2 cwt. distributed between the two or the four jacks. This is, of course, a very severe test, but if you consider that the jacks should be able to withstand such extreme conditions we will arrange accordingly. The present size of jack is ample for lifting purposes, and we propose to retain this on the front axle but to allow for 3/4" more lift i.e. 9" instead of 8 1/4". The side strain on the front jacks is not nearly so great as on the rear jacks owing to the fact that the rear wheels would be held by the brakes on a 1 in 7 gradient. The attachment point of the front jacks is also much lower and the leverage consequently less. We consider that it is better to add as little weight as possible to the front axle. With regard to the rear jacks we note that one of the brackets slipped on the axle in spite of the large clamp employed. It will therefore be necessary for us to fit a 3/8" diameter key to the main bracket casting to provide a definite key, and to drill a hole in the axle casing to register with it. We did not do this previously because we did not want to interfere in any way with the axle. In this connection | ||