In order to get the access panels to secure to the turtle deck I would need to use nut plates. To get the access panels to sit flush with the turtle deck I would need a way to dimple the turtle deck holes while at the same time have a flush surface to rivet the nut plate to. So, I designed these 0.063 mounting plates that sit between the dimpled skin and the nut plate. These mounting plates are countersunk for the AN426-3 rivets. Now, you may be asking, why not use NAS1097 rivets with the low profile neck? Well, because they are just not going to sit as flush as this solution. So, I fired up my cnc mill, loaded a scrap plate that had already been primed and cut a bunch of them out. I also decided that I will make all of the access panel screws #10-32 torx to keep things simple.
