The pre drilled factory trim tab has some fairly significant burrs on the inside So, how do you get rid of those when the normal deburring tools are too big to fit inside?
I use a small piece of a Vixen file double sticky taped to a yard stick The vixen file will slide flat across the holes, removing the burrs, but not scratching the surrounding material
The vixen file works well on any flat surface. Just slide the file back and forth across the line of holes with your fingertips.
If you are an over achiever, tape or bond with epoxy to a wooden handle for ease of use.