Swelling of journal

• Fillet is added to some points on the crankshaft to avoid sharp edges or stress concentration at a particular point .
•  So the point where we add the fillet, at that point we can't put main bearing so , because of this the size of the crankshaft increase which is called swelling of the journal.

Fillet : Fillet is a radius created in the transition from the con rod or main journal to the vertical portion of the crankshaft.The radius improves crankshaft strength but requires a slightly narrower bearing compared to stock production bearings