[BITList] Fwd: [BIship] Rajula crankshaft failure

[HUGH]

Mike,

Engine builders didn't hold spare crankshafts, or even spare journals, 
crankpins or webs.  My fellow apprentice, Joe, and I built one or two triple 
expansion crankshafts, and there were no castings involved - I don't 
understand the references to blow holes in castings in the text.  The webs 
were flame cut from forged billets, and the pins and journals were machined 
from forgings.  I can conceive of no good reason why the failed journal 
should have been made with a non-radiused step down in diameter.  Normally 
all of the journals would be the same diameter (the diameter is a factor in 
the torsional vibration calculation) - the report doesn't mention the other 
3 journals or their diameters.  Perhaps the journal was remachined at some 
point in Rajula's career, but in that case I'd expect there to have been a 
record of it.

Hugh.