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).
Solutions for loose control ball joints in levers, including modifications to drawings and dimensional tolerances.
| Identifier | ExFiles\Box 66\4\ scan0274 | |
| Date | 1st August 1925 | |
| To BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. to CJ. Hs.{Lord Ernest Hives - Chair} 48320 E1/MS. 8.25. CONTROL BALL JOINTS. X. 9240 X. 8310 X. 8320 Regarding the trouble that has been experienced with control balls coming loose in levers, Mr. Royce is of the opinion that the hollow riveting can yet be made a successful production job, and we attach herewith drawing LeC.2118 shewing certain modifications to LeC.1726. At the same time we have some criticisms to offer on the details issued to the Works, as follows :- (1) The diameter of the stem on the Derby detail is .187 whereas we call for .218 on LeC.1726. Mr. Royce thinks the larger stem is absolutely necessary to make a good job. (2) The Derby dimensions on the stem and hole give a possible max. clearance of 12.5 thous. with 5 thous. tolerance on each. We cannot see the need for a minimum clearance of 2.5 thous. Mr. Royce is of the opinion that the hole should be reamed and the stem should have say a 2 thous. tolerance, also that selective assembly should be used if necessary to ensure a better fit. LeC.2118 shews a chamfered hole in the lever so that the rivet can be expanded with a punch to fit diametrically. E.{Mr Elliott - Chief Engineer} | ||