brother in law did this with a 9" grinder , he was trying to cut a 12" gravel board for a fence in half so he didnt need to go to B&Q to get 2 6" ones. Needed air ambulance will never run again he was lucky as was really close to cutting main artery , was touch and go as it was. I had to finish fence while he was in hospital forgot my 9" and had to use his was a bit anxious at first as still his claret all over the blade. He got rid of it as soon as he got home from hospital. Still dont get how he did it but when i picked grinder up for the fist time side handle was on as if he was left handed so reckon he was using it cack handed.
View attachment 166376
Very nasty and could have been a lot worse.