WHILE ADJUSTING THE BELT TENSION ON A MOTOR RUNNING A BELT DRIVEN MACHINE BORING HEAD, THE MOTOR WAS TURNED ON BY THE OTHER EE WITHOUT CHECKING TO SEE IF THE INJURED EE HAD HIS HANDS AWAY FROM THE BELT. WHEN THE MOTOR TURNED ON IT GRABBED THE EE'S HEAVY WELDING GLOVES AND PINCHED IT BETWEEN THE BELT AND THE SHEAVE. RESULTING IN A SMALL FRACTURE TO THE LEFT INDEX FINGER.