The same can occure with wood, have seen the remnants of a 6" wheel after a seaman replaced several hammer handles grinding the tops into shape and clogging the wheel then went to sharpening cold chisles , had to press hard cause the wheel wasn't working properly , all got hot and boom, blew a bloody great chunk out the front and side of the wheel but the lucky idiot wasn't hurt , came and complained that the grinder wasn't working properly and was shaking when it ran , yes he had run it again and tried to use the other wheel it was so out of balance I had to skim the rotor where it touched the case and replace all the bearings :oo: