7-46. If itis necessaryto make astandard shaft journal
surface more than 0.003 inch undersize or a renitrided
0. 003 inch undersize more than 0.006 inch
undersize, the crankshaft must be ground to undersize
and renitrided. Standard shafts may be ground to 0. 006
inch or 0.010 inch undersize, renitrided 0.003 inch
undersize shafts must be ground to 0. 010 inch undersize.
Shafts must be fitted with the corresponding
undersize bearing inserts. Grinding the crankshaft is
a delicate operation requiring adequate grinding facilities
and a great degree of skill. A properly dressed
wheel (Carborundum (GA54-J5-V10 or equivalent) must
be used with generous amounts of coolant. The wheel
must be fed to the journal or pin very slowly and the
final ground finish maintained during the complete operation.
This procedure must be followed to eliminate
possibility of grinding cracks. After grinding, the
crankshaft must be carefully inspected by the magnetic
particle method. If any cracks or checks are found, the
shaft must be rejected.