Employees were servicing a tool and attempting to remove the pivot pins while the tool was in the horizontal position. The first employee was kneeling and facing the tool, while a second employee was operating the grab handle to remove the pivot pins. The first pivot pin was successfully removed. While attempting to remove the second pivot pin, the second employee rotated the handle from the unlock position to the lock position. He then rotated the grab handle downward. During this operation, the pivot pin came out and allowed the grab handle to rotate past its normal stop (lock position). The second employee's right middle finger was then caught between the grab handle and a weldment, resulting in a fingertip amputation.