Then I used various sanding drums to finish out the hole until it matched. I wiped the parts with MEK and primed them. Instructions say to prime the bottom of the pitot bracket shaft so that dis-similar metals, chrome and aluminum, have primer in between them. Then I reinstalled the mounting plate and angle and used -4 flush rivets to rivet the angle to the rib. The plate will get rivetted on when I rivet on the bottom skin.
