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).
Technical letter detailing the development and specifications for brass tubing used in lubrication systems.
| Identifier | ExFiles\Box 127\3\ scan0056 | |
| Date | 1st July 1935 | |
| Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} BY/EM.31/J.1.7.35. BRASS TUBING FOR LUBRICATION SYSTEM. -------------------------------------- We return herewith your letter in regard to the above and have to say that we have not so far discovered any signs of the flaking trouble referred to. If this trouble really exists, it would appear to be due to faulty manipulation of the tube and we cannot see any reason why copper tube from the same source should be any freer from such defects than brass tube. As a matter of fact, the development of a suitable brass tube for lubrication pipes has caused us very considerable trouble and concern and our present quality has only been arrived at by considerable experiment both on the part of our suppliers and also ourselves. In the first place the tubing we use for this purpose was in the hard drawn condition and we found that it was extremely susceptible to season cracking and longitudinal splitting and satisfactory tubes could not be produced in this manner. Finally, in conjunction with our present suppliers, Messrs. James Booth & Co, Limited, Argylle Street, Nechells, Birmingham, we developed the present tubing which is supplied in the medium hard condition and we insisted that the tubing shall be suitably annealed just before the last pass through the dies and we consider it is this last pass which cleans the tubing both internally and externally so that it is free from defects especially internal defects such as described. In addition to the above, we have found it necessary to insist that our suppliers pressure test every length of tube they supply to us and this also serves a double purpose as firstly it ensures that the bore of the tubes is clear and free from stoppage and secondly, it is designed to show up any defects of manipulation such as seaminess or cracks if they exist. The composition of the brass tube we use is:- Copper - not less than 69% Tin - not more than 1.25% Total Impurities not more than 0.75% Zinc the remainder Cont'd.{John DeLooze - Company Secretary} | ||