This afternoon, we got the engine mount match drilled to the weldment brackets behind the firewall. This is a two person job, so I employed the help of my buddy Sean.
Before I attempted drilling, I talked with fellow RV10 builder Justin (http://buildingrv10.blogspot.com/), who happens to be about the same place in the build as I am. He mentioned that it might be best to start with the center two lower holes, and work your way out and up. This contradicts the plans, as they have you start with one of the upper holes. Well this is fine in theory, but in reality, the entire mount is a little tweaked from the welding process. For me, all the bottom holes lines up (in relation to each other), but the upper two holes in the mount needed to be pulled outward to get them to line up. Since I started in the middle, each top hole was about the same distance off, and pulling the mount into position was easy enough to do by hand. Had I started on one of the top holes, I would have had to pull the entire distance at once to get the second top hole to line up… which would probably been difficult.
In the end, the mount is drilled, and everything lined up. Justin’s recommended procedure worked great!