Blind Drilling Fairing

Today was a long, not fun day in the shop where it felt like little was getting accomplished. At least if wasn't obvious. I spend more hours sanding and trimming the fairing flange to improve the fit around its perimeter. Particularly where it meets the horizontal stab leading edge. It was messy, dusty work in the heat wearing a dust mask. I finally got it as good as it was going to get. Then it was on to blind drilling the mounting screw holes using the magnet technique. Van's supplies these small, spherical and surprisingly powerful neodymium magnets. You place one inside the structure over the preexisting #40 hole. Place another magnet on the other side of the hole and they are held fast, centered in the hole. Place some tape over the inside magnet to secure it. Remove the outside magnet, slip the fairing in place, and replace the magnet over the now blind hole. It sits in a small plastic washer. I took some machine oil and lubricated the washer so it would slide easily over the fairing and have less resistance to perfectly centering. I wiggled the exterior magnet in the washer around and it would slide back to its centered position over the hole. Remove the magnet and mark the inside of the washer with a marker. Remove the washer, pray, then drill a #40 hole on the mark. Repeat as needed. I got the first 8 holes done. Some holes were dead centered. Others not as much. I expected that. I jumped on the VAF forum prior to see if there were any better techniques but could find none. The holes will be upsized to #27 for a #6 screw. The off-center holes I'll gradually upsize and use some drill "English" to hopefully center up the holes as I go. I hate spending so much time on one part to get it right. When it's completed, I'll have days on it. I also ordered fiberglass countersinks from a British company called Permagrit Tools. They make specialty grit based vs metal cutting countersinks for fiberglass. I ordered their 5 piece kit with the typical sizes I'll need. They're popular for guys building composite planes and boats. I wasn't happy with the countersinks on my rudder fairing and think these new tools will help.