Seeing as Scott asked in the second vidja he made and the possibility of any other new evidence being found, one theory could be possible that there's a link between the broken fin and the broken base. They do have the relationship of an earlier partial break and while not probable, it would not be impossible for the saw to fall/drop on something just right to cause such an affliction as that area of the cylinder is somewhat exposed. Again, just a theory, surely Scott will keep poking around on this and get it whittled down after all the evidence is in and his CSI investigation comes to a conclusion.