EE WAS REPLACING THE GRINDING WHEEL ON HIS 4"" GRINDER WITH A 40 GRIT SANDING WHEEL IN ORDER TO ROUGH UP A PIECE OF STEEL TO PUT DOWN NEW RUBBER. THE SANDING WHEEL CAME INTO CONTACT WITH THE OLD PIECE OF RUBBER. GRINDER JUMPED OUT OF C0NTROL & CAME INTO CONTACT WITH THE INDEX & MIDDLE FINGERS OF HIS LEFT HAND.