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).
Tolerance limits for ball bearings in the 25HP & Peregrine gearbox.
| Identifier | ExFiles\Box 179b\1\ img047 | |
| Date | 6th September 1932 | |
| ORIGINAL FROM HDY.{William Hardy} C. to EQ, SGN, KC. [strikethrough] C. to E, B, HS.{Lord Ernest Hives - Chair} RHO. [strikethrough] HDY{William Hardy}/M6.9.32. x5310. x4027. 25HP. & PEREGRINE GEARBOX. R.{Sir Henry Royce} has remarked that instead of using the close limits of plus or minus 1/10/1000" on the 3rd. motion shaft for the ball bearings as shown on G.55561., the inner bearing should be slightly larger in the bore, say 10/1000". We are aware that the need for this close tolerance arose through difficulty sometimes experienced with the ordinary 1/4/1000" limit in passing the inner bearing over the surface for the outer bearing, and we presume that the difficulty is accounted for by the necessity for selection of bearings to get the required tightness when a shaft limit of 1/4/1000" is used. HDY.{William Hardy} [STAMP] RECEIVED 4 SEP 1932 | ||