EE WAS ASSISTING SECOND EE IN THE REMOVAL OF A NUT FROM A STUD BOLT. THE SECOND EE WAS USING AN IMPACT WRENCH TO REMOVE THE TOP NUT OFF OF THE BOLTS. THE INJURED EE RECEIVED A LACERATION TO HI S LEFT RING FINGER WHEN HE GRABBED THE BOLT THREADS WHILE IT WAS TURNING. FOUR SUTURES TO CLOSE, NO LOST TIME OR RESTRICTTIONS.