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 suspected cracks and inclusions on a Bentley V8 cylinder crankshaft.
| Identifier | ExFiles\Box 124\2\ scan0338 | |
| Date | 19th August 1941 | |
| C.T.S. Any signs of bearing failure since Crank changed? To: Rm.{William Robotham - Chief Engineer} 10244 Fte Rm{William Robotham - Chief Engineer} BENTLEY V.{VIENNA} re:- 8 Cylinder Crankshaft I succeeded in locating the crankshaft late last week, and had a look at the centre bearing. I expected to see quite a gaping crevice, to my astonishment one had to use a glass to find any fault with the centre bearing at all. Actually, there is one straight line which looks to me more of an inclusion than a crack, its approximate length being 5/16 of an inch. This cannot have caused the trouble reported. In addition to the axial crack referred to in the last paragraph, there are a number of cracks in the radius where the journal runs out into the web. These are grinding cracks and can only be surface effects. I am sending the crankshaft into HL/GLT after showing him the defects, and we are collaborating to settle two points:- (a) Is the straight line in the journal an inclusion or a crack. What is its depth?. (b) Is the material sensitive to grinding, as unless the Brinell is high, I should not expect to see grinding cracks in the radius, particularly as there are none on the thread faces, as far as I can see. Finally, the failure of the centre bearing had nothing to do with these cracks. I would like a sketch showing the method of lubrication of the centre bearing. By.{R.W. Bailey - Chief Engineer} | ||