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).
Investigation into damaged Bentley connecting rods and bolt failures from depots.
| Identifier | ExFiles\Box 85\3\ scan0121 | |
| Date | 21th August 1937 | |
| Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} from RHC{R. H. Coverley - Production Engineer}/Cy. Siles RHC{R. H. Coverley - Production Engineer}/Cy.1/LS.21.8.37. 24 SWD2 BENTLEY - CONNECTING RODS. During our investigation of your complaints on Repair Connecting Rods, we found on taking two sets at random from Repair Department, that several bolts had been scrapped by stretching, and some by re-screwing with an incorrect Die, as evidenced by difference in pitch. Other bolts have been damaged by forcing down nuts and badly burring the thread. These rods and bolts are exactly as received from Depots. Obviously this is very serious, and all depots should be advised of the necessity of providing suitable spanners of correct length, particularly in the case of Box Spanners, as these are always open to abuse by using longer Tommy Bars. Normal tightening with a correct length bar in the Box Spanner will not stretch the bolts. We do not agree that there is the slightest necessity to re-screw any connecting rod bolts after service. They are carefully made in the first place, and we can guarantee a good job, as every care is taken in manufacture and inspection. Bolts in the above faulty condition cannot be expected to rigidly hold the joint faces of the rod and cap together. We find that Repair Rods are out of round in the bore, with the major axis in line with axis of the rod, and ovality varies up to .005. We know the bores are correct for size, parallelism, and circularity when they are finally ground before assembly. We are investigating the question of distortion in Service, and a further report on our findings will be issued later. RHC{R. H. Coverley - Production Engineer}/Cy. | ||