Next move over to the chop saw, we are going to cut the miters on the chop saw. Set the chop saw to 45 degrees. next set up a stop block, you want each one of the cuts are the same length. If the sides of the boxes are a little off, it will not line up, when you are ready to glue and nail the corners. Keep in mind when you are using a stop block you want to hold the martial on the side of the stop.