I have heard of this but never seen it happen. hope I never do. http://news.yahoo.com/video/us-15749625/security-camera-captures-giant-runaway-saw-blade-19240040
Oh yeah,I've seen this happen in person. Happened about twenty years or so ago in upstate NY. I was working for Alcan rolled products in Oswego,NY. That day we were cutting out old concrete floor with this same type of floor saw. The next day I along with my boss didn't check the blade that morning. Started the thing up and after about a minute the blade goes flying off and running across the floor. Hit a I beam, corrugated metal siding and outside .This was in the re-melt shop with gas lines,people,hot metal ect all around. Nobody was hurt,just scared the poop out of us both. Slagpot
We had one shoot thru a four lane into the guardrail where it flew in the air lost momentum. Was extremely sickening to see because I was in the backhoe watching it miss cars by feet. Funny thing was nobody stopped or said anything afterwards. We got together and made it a rule the operator makes all adjustments to machine before operation and after. Just another goofy thing that happen to us was we lost a steel plate off a silt fence machine twice in a month. First time bounced off car hood behind the semi . Cost company out of pocket money. Since this was a truck driver issue it was caulk up as not securing the load. Two weeks later with a new Class A driver it happened after I personally tightened the lock bolt to the rear plate. It flew over my truck after bouncing atleast 50ft in the air and shot out to the ditch. We could of just drilled a locking bolt thru the rear shaft but decided for now on plates ride in semi. That plate reminded me off that saw blade when in bounced in front of me, lesson learned.