Whats wrong with this picture ?

The following photo is a close up of the arbor on my 10″ Delta Contractors saw (model TS350).  I purchased this saw new in 2004 at Lowe’s, and until today it’s done everything I’ve asked of it.

Give up?  It’s not a consistent diameter, the threaded section is 0.610″, the non threaded section is 0.557″, & the standard mounting surface is 0.6245″ (what it should be). So what does that mean? Well that nice Freud dial a dado set I just purchased is essentially useless on this saw.