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).
Assembly, clearance, and production issues of connecting rod small end bushes.
| Identifier | ExFiles\Box 132\2\ scan0243 | |
| Date | 26th April 1938 | |
| 1119 To: Bm & Rm.{William Robotham - Chief Engineer}...From RHC{R. H. Coverley - Production Engineer}/SB.{Mr Bull/Mr Bannister} c. to HPS.{Horace Percy Smith - Experimental Factory Mgr} c. to Hs.{Lord Ernest Hives - Chair} Rodes RHC{R. H. Coverley - Production Engineer}/SB.{Mr Bull/Mr Bannister}1/MC.26.4.38. SWDL{Len H. Swindell} See me Pim CONNECTING ROD SMALL END BUSHES In reply to Rm{William Robotham - Chief Engineer}/Swd1.1/AP.21.4.38., the proposal to use bushes selected to suit individual rods with .0001-.0002 clearance will not overcome production troubles, and the use of selectively fitted bushes was actually only recently abandoned in favour of a press fit. The connecting rod bore and bush were formerly dimensioned size and size with ± .00025 limits, but trouble occurred due to a percentage of the bushes being tight which necessitated final reaming in position, and the latest procedure of providing a definite .001 interference with final diamond boring in position was, therefore, adapted. [Diagram Annotation] BUSH PRESSED OUT To REMOVE CHIPS WHICH PASS THRU' HOLES INTO GROOVE WHEN BORING It is at present necessary to press the bush over half way out of the connecting rod after final boring in order to remove bronze chips which collect in the oil groove, and to avoid boring in position the bush must have .00025-.00075 positive diametral clearance. It is considered that the positive oil feed to the small end will be sufficient to prevent knocks occurring with the floating bush, and we, therefore, recommend that B.III. No.5. unit be assembled with .00025-.00075 diametral clearance on O/D.{John DeLooze - Company Secretary} of small end bushes, which procedure should be standardised if satisfactory. RHC{R. H. Coverley - Production Engineer}/S.Bannister. | ||