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).
Interview with John Thompson Motor Pressings Ltd. regarding the production of 'Goshawk 11' side members.
| Identifier | ExFiles\Box 75\3\ scan0321 | |
| Date | 9th September 1932 | |
| 100 T; (S H.{Arthur M. Hanbury - Head Complaints} 798, 10-12-30) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2047 X4260 Copy for HS.{Lord Ernest Hives - Chair} FO 9 SEP 1932 WD{Mr Wood/Mr Whitehead}/Jun.9.32. By.{R.W. Bailey - Chief Engineer} from Wd.{Mr Wood/Mr Whitehead} RECEIVED X4260 "Goshawk 11" - Side Members to blueprint F.50,000/1. At the interview which we had with Mr. Aston, Director of John Thompson Motor Pressings Ltd. this morning, he expressed the opinion that the most economical course we could take in respect of the above-mentioned Side Members would be to have them hot pressed out of Mild Steel plates, instead of out of 3% Nickel plates. Owing to the alleged impossibility of producing evenly rolled plates of the thickness originally specified for "Goshawk" Side Members, we lately authorised Thompsons to order plates .125" thickness, allowing them plus and minus limits of .005". And they are daily expecting delivery of some plates of 3% Nickel of this thickness and it will then be seen whether the increase in thickness we have agreed to has enabled suppliers to roll plates of uniform thickness. The price we have agreed to pay for Side Members of 3% Nickel Steel, hot pressed from plates of the thickness here mentioned, is £15.0.0d. per pair net, this covering the cost of dies. Thompsons experience goes to show that the desired uniformity in thickness cannot be obtained in plates thinner than .156", with plus and minus limits of .0075", and they suggest that the most economical course would be to have "Goshawk" Side Members hot pressed out of Mild Steel plates of this thickness. They are of opinion that if we agree to this, the price of the Side Members could be reduced to £12.15.0d. per pair and the existing dies will serve. They recommend that steel of 32 to 36 tons tensile strength be employed, with an analysis approximately as follows:- Carbon......... .26% to .30% Silicon........ .03% " .05% Manganese...... .5% " .6% Sulphur........ Not more than .06% Phosphorus..... " " " .06% We have pointed out that we should not be prepared to agree to a sulphur and phosphorus content of more than .05%. Thompsons also suggested that we might consider cold pressed Side Members. They pointed out that the dies for producing cold pressed Side Members are very expensive; in fact (contd) | ||