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).
On the procedure for rectifying bowed crankshafts by stoning and lapping as an alternative to regrinding.
| Identifier | ExFiles\Box 146\3\ scan0158 | |
| Date | 2nd November 1936 | |
| EM/Sadl.1d/JH.2.11.36. CRANKSHAFTS. With regard to regrinding of crankshafts, this is not really a satisfactory job in that it is generally found that after considerable running the crankshaft is bowed in the centre. This may be to the extent of .010" and in order to grind true off the crank centres, an excessive amount would have to be ground off necessitating re-nitriding etc. Although this would make a satisfactory assembly job, the crank would have the same bow in it when next dismantled. On the maximum diameter of the journals we have never registered any wear more than .001 and .003 on the minimum diameter. The most satisfactory way we find is as follows:- Stone down the grooves in the crank journals and then lap each one on machine until true. For the first dismantling the journal diameter could be reduced in lapping by .003 without seriously affecting the hardness figures which are originally obtained on the surface. Any lapping or grinding in excess of this should be done in conjunction with rehardening by nitriding of the crankshaft. EM/L.H.Swindall. | ||