EMPLOYEE WAS USING A POCKET TYPE KNIFE TO CUT TIE-WRAPS LOOSE FROM A HEAVY EQUIPMENT FUEL LINE. THE KNIFE SLIPPED THROUGH TIE-WRAP & MADE CONTACT WITH EE'S LEFT ARM SEVERING HIS RADIAL ARTERY. EE HAD SURGERY TO REPAIR ARTERY & WAS RELEASED TO NORMAL DUTIES AS A MECHANIC LEADMAN, NO RESTRICTIONS.