I finished making a very small cut about 1/16 inch and shut down the saw. As if powered down it made a great racket. When the blade finally stopped spinning I took a look and found the nut was spun off about 1/4 inch or more. I had been switching back and forth between a cross cut and rip blade. The only think I can think of is I failed to tighten the nut after the last change.
Is there anyway a blade snugged up with a wrench to work loose? What if it had just been finger snugged?