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).
Recommendations for crankshaft and bearing wear on Chassis B.6.BN, including regrinding procedures and material specifications.
| Identifier | ExFiles\Box 146\3\ scan0190 | |
| Date | 30th November 1936 | |
| 1265 W/P. To Sr. from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}3/AP.30.11.36. CRANKSHAFT & BEARING WEAR. CHASSIS B.6.BN.{W.O. Bentley / Mr Barrington} (Mr.E.E.Blanc) With reference to crankshaft wear which has taken place on the journals in the above car, we recommend that the following course be taken. The crankshaft be put in the hands of Messrs Aubert & Duval for the regrind, who according to reports have had experience with nitriding since its inception. Considering the excessive wear which has taken place on No.4., the centre main bearing, it would give useful information if when it is fixed in the machine centres the bow in the shaft, if any, be measured. The figure of .015" which you quote for the regrind should cover the amount of bow and wear in order to produce a true crank. Regarding your query; it is not necessary to give the crankshaft any treatment before regrinding; further, after regrinding and re-nitriding, the crank should have a final light lapping in order to give the requisite finish to the surfaces. We give herewith the particulars of our V.C.M. crankshaft which can be given to Messrs Aubert & Duval for their use in re-nitriding of the shaft - Carbon .25 to .35% Silicon (not more than) .35% Manganese (not more than) 1.0% Sulphur ( " " " ) .05% Phosphorous ( " " " ) .05% Nickel ( " " " ) 1.00% Chromium .5% to 1.5% Molybdenum .9% to 1.5% Nitriding 475°C plus or minus 5° for 80 hours. Depth of case .010 Hardness of case Not less than 600 Vickers Diamond hardness. Hardness of core Brinell 248 - 293. continued | ||