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).
Article detailing the process and benefits of repairing worn metal parts using electro-deposition, with photographic examples.
| Identifier | ExFiles\Box 50\2\ Scan161 | |
| Date | 5th November 1920 guessed | |
| half the cost that you would have to pay for new parts, and with less delay than you would, in many cases, experience in getting them.” That, undoubtedly, is an attractive and a practical proposition. If it can be carried out, it means literally the abolition of the scrap heap, that bugbear of an engineering shop to which most people have become so accustomed as to condone. Times are too hard to-day for a mounting scrap pile to be regarded with complacence, and it can be said, without exaggeration, that if this process of electro-deposition has been made a practical proposition, a new era in repair shop practice will have dawned, equally as significant as the coming of autogenous welding, and which promises to cover an even wider field of utility. A Pioneer Plant. We recently had the opportunity of inspecting the laboratory and workshops in which this work is being done. Though we are not at liberty to publish very detailed particulars of the process, we were given ample opportunity of inspecting it and of satisfying ourselves as to its undoubted success in the applications to which it has so far been put, and as to the high quality of the work which is being turned out. Worn parts, when received at the works, are first of all checked, registered, labelled, and allotted a job number. They are then carefully measured up by micrometer, and the amount of wear which has to be made good determined. The area of the worn surface is also measured, and the anperage of the current which will be required in the deposition process estimated, and entered on the label, as a guide to the operators. Various other particulars, such as the finished size to which the worn portions must be rebuilt, are also entered on the label, which is attached to the part throughout the process. After this preliminary inspection, the part passes to a department, where it is coated entirely with a substance impervious to the electrolyte, in which it eventually will be immersed. The protective coating is then removed from the portions on which new metal is to be deposited, and the parts are subjected to a very thorough cleaning process, to remove dirt and grease, after which they pass to the electro-deposition benches. Here, immersed in vats, and surrounded by vibrating anodes of suitable material, they remain until the requisite thickness of metal has been deposited on them. The amount of the deposit can, we were informed, be accurately determined and controlled to within half a thousandth of an inch. Parts That Can be Treated. It may be of interest here to enumerate a few of the parts which were under treatment at the time of our inspection. They included gearbox shafts of all descriptions, change speed and brake operating gear, ball bearing housings, swivel arms, gudgeon pins, shackle pins, and many other wearing parts. Amongst finished parts we noted a stub axle on which a layer of new metal 15-1000 in. thick had been deposited, a large gear shaft which had 5-1000 in. added to it, a splined clutch centre to which 90-1000 in. of new metal was added to the splines, and a swivel arm with the same amount—to quote a few examples. Some of them had been case-hardened in the Richmond gas-fired furnaces with which the plant is equipped—for the built-up parts can be heat-treated as desired. Afterwards they are ground accurately to finished size in the machine shop which has been installed. It must be noted that cast-iron parts cannot yet be treated by this process. At present, the work of renovation is confined to parts made of steel—of which, naturally, most wearing parts are made. Later on, perhaps, other materials may be dealt with. It may here be as well to sound a note of warning. Since the principle of electro-deposition has been known to be applicable to the renovation of worn parts, a number of people have attempted to dabble, in a more or less experimental way, with the process. Few of them have achieved any real success. The process is too delicate and involved to present any reasonable prospect of success to the amateur investigator. It calls for an amount of accumulated experience which can only be obtained by prolonged experiment and research; moreover, such experimental work involves very considerable expense. From what we have been permitted to see at the Electro-Ferrous Engineering Co., Ltd.'s laboratories at Caversham, however, the process has there been standardized and perfected to an extent which conveys the idea that there, at any rate, it has passed from the stage of experiment to that of commercial practice, and that the manner in which it is being tackled signifies—if not the birth of an entirely new industry—a development which is likely to have the most far-reaching importance in the science of motor vehicle repairs and in engineering repairs in general. The above illustrations show the utility of electro-deposition. A variety of worn parts which have been treated by this process. The bright portions are where new metal has been added to replace that worn away. TEMPLE PRESS LTD. LONDON E.C. | ||