EE WAS HOLDING AN ALLEN WRENCH WHILE 2ND EE USING AN AIR WRENCH TO TIGHTEN NUT. THE WRENCH SPUN THE NUT UNTIL IT CAUGHT, SPINNING THE BOLT, WHICH CAUSED THE ALLEN WRENCH TO SPIN. THE ALLEN WRE NCH CAUGHT THE EE'S FINGER BETWEEN THE FRAME AND THE WRENCH. THEY WERE REPAIRING A FEEDER PAN LINER.