What is self-grind of the wheel

Since grind of the wheel are also known as "self-sharpening."
Grinding wheel action depends mainly on grains exposed sharp edges, during grinding, sharp edges will gradually be worn and blunted, weakened capacity stainless steel cutting wheels.
Then peel off the surface of the grains or broken, thereby forming a new blade grinding, grinding in order to achieve the effect of a sharp, which is self-sharpening.
Sparks generated during grinding is grinding down a portion of another part of the metal debris is broken off or sand.
If the spark is short, it is bound to self-sharpening poor, a reduced ability to grinding, small metal shavings mill under a sand can not afford to, so little spark and short.