Nice to hear of a pleasant experience. He also may have brought the product up on his computer and saw it was for a 10' piece and had 2 considerably...
I have abused regular angle grinders cutting and grinding concrete, tile, stone, brick, etc. for many hours. It takes a while to kill a good grinder....
yes sure ive done big damage, sorry on no photos as they turned out poor but might have one that at least shows. Basically I rounded the leading top...