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).
Visit to Rover Co. regarding their process for chromium plating cylinder bores.
| Identifier | ExFiles\Box 132\5\ scan0034 | |
| Date | 25th January 1939 | |
| COPY. Rm.{William Robotham - Chief Engineer} H1/EA.3/JM.{Mr Morley}25.1.39. Laboratory. Visit to Rover Co. in connection with Chromium Plating Cylinder bores. With Mr. Salt, I yesterday visited the above company, interviewing Mr. Grice. We were shown a scrap cylinder, which had been chromium plated, and this has been brought back to the works. A carefully designed, but simple, jig to hold the anodes in position during plating was also shown to us. So far as I could ascertain there is nothing special in the actual chromium plating operation, but points observed are given below:- (1) The anode jig is mounted on the cylinder casting and the whole assembly is immersed in the plating solution, no attempt being made to "stop off" where plating is not required. (2) A relatively high current (about 700 amps) and short plating time (10-15 minutes) is used. Reversal of current is employed for cleaning and etching. (3) The deposit applied is 0.00075" to 0.001" in average thickness and is honed to approx. 0.0005" thickness. An idea of the section of the deposit as applied is shown on the attached sketch. (4) The procedure is to hone the bore parallel, apply the deposit, hone again. The tapering step does not introduce any difficulty in practice, according to Mr. Grice. They prefer honing to grinding. (5) The chromium extends about 1½" down the bore from the top. Complete plating of the bore has been found a disadvantage when the chromium has become polished by running, the features being piston "pick-up" and increased oil consumption. | ||