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).
Issues with Borg & Beck clutches, including plate flatness, run-out, and packing for transit.
| Identifier | ExFiles\Box 129\1\ scan0250 | |
| Date | 23th August 1937 | |
| To RHC{R. H. Coverley - Production Engineer}/AC. from Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler} c. RHC{R. H. Coverley - Production Engineer}/EG. c. RHC{R. H. Coverley - Production Engineer}/CY. Re. Borg & Beck Clutches. We thank you for your RHC{R. H. Coverley - Production Engineer}/AC.1/DB.{Donald Bastow - Suspensions}19.8.37. With regard to the grinding of the face of the pressure plate, we do not regard an error of say .003 in flatness as a serious matter, because, experience shows that when any plate has been in service for a short time a far greater distortion than this results from the effect of heating combined with the loading of the springs and fingers. Even if we had plates showing a very good bedding when new, it would not last any length of time in service, on the other hand, we attach importance to the finish of this friction surface being as smooth as reasonably possible, i.e. not coarse ground. The same remarks apply to the R.R. pressure plate of the P.III. With regard to the run-out of the driven plate, we agree that these should be within about .010, and this matter has been taken up with Borg & Beck several times in the past for 25.HP. and Bentley and recently in connection with P.III. We have seen a number of plates tested and set at the Borg & Beck works to within .010, and Borg & Beck declare that they always pass them to within these limits, but there is little doubt that distortion occurs during transit and subsequent handling. We are again taking the matter up with Borg & Beck, suggesting better packing, as the plates arrive by road or rail packed loosely in a crate, each plate only being wrapped in one piece of paper. Experience appears to indicate that it will be necessary to check and correct the run-out before fitting in an engine, and this can be done in a very few minutes per plate. Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler} | ||