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).
Analysis of roller and ball race failures, subsequent intensive testing, and material treatment issues.
| Identifier | ExFiles\Box 153\1\ scan0273 | |
| Date | 19th April 1939 | |
| - 2 - The original robust roller used on the 25/30 gave us trouble with the balls and ball races failing. We have in this month's complaint folder (H.1/C.15.4.39) a report of a failure on the road due to a number of the quarter inch balls splitting, on GWN.68 at only 12,600 miles. In view of these ball failures a series of intensive tests were run by Ransome & Marles, simulating road conditions, with an overload of 3600 lbs. between the roller and the cam. Various sizes of balls were tried in small steps until the position was reached at which both the balls in the races and the rollers themselves stood up to the agreed overload, and this is the design still in use, and which was agreed and accepted by the Adamant Co. Our experience shows that when instructions are adhered to, there is no more difficulty in using the material specified than 5% casehardening nickel. The reason the rollers made by us were stopped and re-treated was the urge to get the parts through, and it must not be forgotten there was never any fear of the rollers which required re-treatment being used as the Laboratory were on the watch, knew that they had not seen a sample and went out and stopped work on the parts pending the necessary tests, found they were wrongly treated, re-treated the batch, and the rollers have been tested to destruction and shewn to stand up three times the maximum load imposed by twisting the road wheels from lock to lock without failure. By BY.{R.W. Bailey - Chief Engineer} | ||