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).
Issue of sticking cones in a synchro-mesh gearbox, referencing Buick's lapping process.
| Identifier | ExFiles\Box 13\7\ 07-page099 | |
| Date | 19th September 1931 | |
| REC. FROM DA{Bernard Day - Chassis Design}/HY.{Tom Haldenby - Plant Engineer} X7310 DA{Bernard Day - Chassis Design}/HDY{William Hardy}1/M19.9.31. X523 X7310 X5310 C. to HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} SYNCHRO MESH GEARBOX. STICKING OF CONES. We telegraphed to you yesterday to the effect that Buicks lay much stress on the bedding of the cones, and we give below the words of their instructions: (We are not sending the book in case R.{Sir Henry Royce} wishes to see it.) "Assemble "special" pilot bushing to pilot end of "splined shaft to guide the cam sleeve during lap-ping process." "Lap tapered portions of bronze cone and "second speed "gear cone with fine grinding compound. These "parts should be lapped together by tirning the second gear "while it supports the weight of the cam sleeve assembly "only. Lapping should be done with extreme care, frequent-"ly checking with Prussian Blue to determine contact. Full "contact between cones is necessary. "Remove special pilot bushing" and substi-"tute therefore the clutch gear and lap with cam sleeve, as "outlined above, raising cam sleeve assembly during process." It does not expressly state that this lap-ping is to avoid sticking. As no doubt the Buick cones do not stick in practice it would appear that we can come to no harm by lapping our cones. We have checked the Buick cone angle and find that as nearly as we can measure it is 6°. The Cad-illac full size drawing also measures 6° and so it would appear that we might make a success of 6°, or at least something more near it then 10° that we are going to try when we have have had a little more experience with the box. CONCENTRICITY OF CONES. It appears to us that we can regard the cones in much the same way as we used to have to think of cone clutches. We know that the cone clutch will not function nicely unless the cones are truly aligned, and the driving cone at least must be concentric. We think that for the present, and while we are having trouble with sticking, that we should true up the cones after assembly on their respective pieces by grinding. We mention this as we remember that you were hoping that grinding after assembly would not be necessary. Later on it may be shewn that this is not essential. (1) | ||