Originally Posted by Bucking Bar

My lawn mower has a vertical crank shaft which gets pumped by pistons very hard and regularly as a result of hot, expansive, gasses. If not properly lubricated, the thrust bearing could get really hot, as it grinds away against the shaft causing spalling. The first visible objective indication of impending failure would be smoke.

Therefore anyone who closely mows their wife's lawn without proper servicing of their tools before use might end up smoking a pole.