TWO EMPLOYEES WERE REMOVING A PADDLE WHEEL FROM THE END OF A CONVEYOR BELT STACKER. THEY WERE USING A MANLIFT TO GAIN ACCESS TO PADDLE WHEEL. AFTER UNBELTING THE PADDLE WHEEL INJURED EMPLOYEE GRABBED SHAFT WITH HIS LEFT HAND & PULLED IT OUT OF BARRING MOVEMENT. SHAFT DROPPED 3"" & SMASHED THUMBNAIL ON LEFT HAND BETWEEN SHAFT & ANGLE IRON FRAME. THUMBNAIL WAS REMOVED AT HOSPITAL.