EMPLOYEE WAS GRINDING A 14"" PIPE AND HE WENT TO TURN THE PIPE OVER SO HE COULD GRIND THE BOTTOM. HE HELD THE GRINDER WITH ONE HAND WITH THE AUTO. BUTTON ON AND ATTEMPTED TO TURN PIPE, THE GRIN DER STRUCK HIS KNEE AND CAUSED THE LACERATION 1 1/2"" LONG AND 3/4 "" DEEP CUT.