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 Geo. Salter & Co. Ltd. analysing a broken spring and recommending a new design to prevent over-straining.
| Identifier | ExFiles\Box 95\2\ scan0005 | |
| Date | 6th January 1936 | |
| .X346 ESTABLISHED 1760 SALTER LONDON: 50 LIME STREET, E.C.3. 'PHONE : MANSION HOUSE 5103 'GRAMS : SPRINGBALANCE, STOCK, LONDON. SPRINGS • ROLLER BEARINGS WEIGHING MACHINES • IRONMONGERY SPRING BALANCES • GAUGES TESTING MACHINES • IRON CASTINGS AUTOMATIC MACHINES • TYPEWRITERS MANCHESTER: CHRONICLE BUILDINGS CORPORATION STREET 'PHONE : BLACKFRIARS 9735 GEO. SALTER & CO. LTD., WEST BROMWICH 'PHONE: WEST BROMWICH 0666 (4 lines). 'GRAMS: SALTERS, WEST BROMWICH OUR REF. EWB/PK. YOUR REF. 6th January, 1936. Messrs. Rolls-Royce, Ltd., D E R B Y. Dear Sirs, LES YOUR REFERENCE:- Hs{Lord Ernest Hives - Chair}/Les.3/KW.31.12.35. In answer to your's of the 31st December with regard to the Broken Spring G.83271. We have carefully examined this spring, and tested it, and it is, as you suggest, made from Silico Manganese Steel, the analysis of which is as follows:- CARBON -------- .53% SILICON ------- 1.9% MANGANESE ----- .93% SULPHUR ------ .040% PHOSPHORUS ---- .038% The fracture shews a fine grain, and we cannot trace any flaw in it. The only suggestion we can make as to why it should break is that the material is over-strained when the springs are compressed solid. After the interview our Mr. Bache had with you, confirmed on the 21st August 1935, you will note that we strongly recommended that all Compression Springs should be so designed that they would stand scragging solid without over-straining the material, and we understood that in future you would do away with the design I.83270, and substitute a design with the extra coils which enables the springs to be closed solid without over-straining the material. You remember Continued..... Purchasers of MANUFACTURES of GEO. SALTER & CO. LTD., are requested to notice that they guarantee their efficiency so far as that they will replace any portions that can, in a reasonable time be shown to have failed through defective material or workmanship, but will not be responsible for any damages, direct or contingent, arising from such failure. In case of the occurrence of any strike of workmen, fire, breakdown of machinery, defective castings, or other unforeseen cause of delay the time fixed for completion of the contract shall be enlarged accordingly. All weights, measurements and powers given in estimate are stated as correctly as possible, and any trifling deviations shall not be taken to violate the Contract. Should any dispute arise on this Contract, same to be subject to arbitration. | ||