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).
Analysis of gudgeon pin and piston sizes, comparing actual interference fits with drawing specifications for Bentley Pistons.
| Identifier | ExFiles\Box 86\2\ scan0034 | |
| Date | 24th July 1933 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from RHC.{R. H. Coverley - Production Engineer} X236. RHC.{R. H. Coverley - Production Engineer}6/BE24.7.33. Bentley Pistons EB.495 We give below an analysis of the gudgeon pin and piston sizes, and it will be observed that the actual interference fits of the experimental pistons are less than the clearance given by MX.{John H Maddocks - Chief Proving Officer} It would appear that the drawing limits should be altered, since the interference fits specified appear greater than necessary. DRAWING | No. | Mean dia. of piston bores | Mean dia. of gudgeon pin | Actual Interference | Actual Interference | |---|---|---|---|---| | 1 | .74965 | .7498 | .00015 | .0004 - .00065 | | 2 | .74955 | .7498 | .00025 | " " | | 3 | .7496 | .7498 | .0002 | " " | | 4 | .7496 | .7498 | .0002 | " " | | 5 | .7496 | .7498 | .0002 | " " | | 6 | .74965 | .7498 | .00015 | " " | ANALYSIS OF EXPERIMENTAL PISTONS | 1 | .7496 | .7497 | .0001 | " " | | 2 | .7496 | .7497 | .0001 | " " | | 3 | .7496 | .74975 | .00015 | " " | RHC.{R. H. Coverley - Production Engineer} | ||