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 John Marston Limited discussing the weight and cost variations of Mark VI cores based on material thickness.
| Identifier | ExFiles\Box 150\3\ scan0068 | |
| Date | 16th October 1936 | |
| X1280 IMPERIAL CHEMICAL INDUSTRIES LIMITED. FROM JOHN MARSTON LIMITED. TELEPHONE: 21481 (4 LINES) TELEGRAMS: SUNBEAM, WOLVERHAMPTON. CODES: A.B.C. 5TH & 6TH EDITIONS; BENTLEY'S. Reply to be addressed to John Marston Limited for the attention of JLC/IE WOLVERHAMPTON. 16th October, 1936 [Logo: NATIONAL SCHEME FOR DISABLED MEN] STEADMAN h {Arthur M. Hanbury - Head Complaints} /w HS {Lord Ernest Hives - Chair} /STD Messrs. Rolls-Royce Ltd., Derby. For the attention of Mr. Steadman. Dear Sir, We have carefully considered the question of the weights of the Mark VI cores referred to in your letter of the 12th inst. The average calculated weight of these cores is .006 and .004 strip as shown in the table accompanying our letter of the 15th ult. is 52 lbs. Actually the average weight of over 50 of these cores is 52 3/4 lbs. Owing to the usual manufacturing variation the .003 strip was in this instance on the full size so that if none of the material exceeded the minimum thickness the saving of weight should be increased from 4 to 6 - 7 lbs. The variation of 5% in the weight of strip is harder to maintain in the case of material as thin as the 0.003 strip. There is also some variation in the amount of solder picked up. With regard to the cost of blocks made with .003 centres this material is considerably more expensive than the .004 copper strip and also it is, owing to its thinness harder to fabricate, so that we could not make any reduction in the cost of such cores. Yours faithfully, John Coltman | ||