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).
Progress report on the production of cams for Marles Type Steering, detailing manufacturing issues.
| Identifier | ExFiles\Box 153\2\ scan0340 | |
| Date | 25th June 1937 | |
| RHC.{R. H. Coverley - Production Engineer} c. Hoy/AW. c. Mr.Hardy 1300 RHC{R. H. Coverley - Production Engineer}/EG.1/DB.{Donald Bastow - Suspensions} 25.6.37. (dictated 24.6.37.) MARLES TYPE STEERING. I proceeded to Adamant Eng. Co., today to ascertain progress of cams particularly 25/30 HP., which are now being produced by the altered operations suggested by Comm.Matravers. We were able to get six 25/30 cams finished during the day, and I tested these during operations and have brought them back with me. The roller track is definitely much more consistent than it has been on recent deliveries regarding the freedom from error of slack portion in centre and hard contact area on either side of centre, and according to test readings taken on inspection rig should assemble with roller satisfactorily. The new method of production has however thrown the whole of the heat treatment distortion, and broaching error in the bore for Steering Tube and this may cause some binding of tubes in bush at top of column. I warned Comm.Matravers of this possibility when he suggested altering the operations, upon the occasion of the visit of Mr.Hardy and myself, but I am hoping we shall be able to accomodate the errors that exist. I did not delay the production of the 25/30 Cams to check this error but checked a new PH.111 which had been produced by the new method and it showed .040" out of truth on a bar which extended 29" from end of cam. This amount of error "I am afraid" is going to cause us some trouble, and I pointed this out to Comm.Matravers and he is arranging to have a smaller amount of metal left in bore before cutting to prevent the broach running so much in final broaching. There is no tolerance margin between a soft cam direct from the machine and our requirements on a finished cam so far as the relation of roller track and bearing diameters are concerned, therefore unless we can allow a reasonable out of truth error in the bore, the cams will have to be cut on an eccentric mandril or ground after hardening unless the smaller broaching allowance meets the requirements. contd....... | ||