After cutting and finishing the wing tie down spacers, I next attacked the wing tie down brackets. I first used my bench sander and 1.5" belt sander to trim the AEX aluminum. I tried to be careful here because the amount of material to trim off is almost insignificant, its only about 1/32nd of an inch. After trimming the material, I marked the poisition of the guide hole at the top right, then used a tap and die set to cut the 3/8 - 16 threads into the AEX while it was secured in the bench vise.
