I needed to do a compass alignment in my RV9A and the key with the triangular recess was nowhere to be found. So I made one that worked great. I had a small round paintbrush with a tapered plastic handle that I cut off at the diameter of the adjustment hole in the compass. I took a T-10 Torx bit and heated the tip with a heat gun, although a torch would work just as well, and inserted the hot tip into end of the handle. I left it in the plastic handle and dribbled ice water on it to cool it quickly. Pulled the Torx bit out and have a tool that pushes over the triangular adjustment screws that is non magnetic. Cost, about a $1...