Final drilling of skins to rudder skeleton

This weekend I continued to work on preparing the rudder for final assembly and riveting. As with the vertical stabilizer, the sequence is to cleco the entire assembly together, match and final drill, disassemble, deburr, dimple, prime and put it back together again. As I’m handling, I’m trying to be very cautious of the skins which are only 0.016” (0.4mm) thick. I’ve heard that it’s very easy to ding, tent or bend these during the various assembly processes.

One of the critical elements of this step is to final drill the trailing edge wedge to the two skins. The plans require that this is done perpendicular to the cord-line of the flight surface. I did this by fixturing the assembled rudder vertically with the trailing edge up, then I final drilled level, or perpendicular to the vertical rudder (not rudder surface). This seemed more intuitive to me than trying to figure out how to find the right angle with the rudder laying on one side.