Weeks back when I did the major cowling work I knew I had some issues with how the top and bottom cowl matched up in the area of the spinner. At the time, I figured I would likely have to "pull" the pieces into place with metal fasteners, but I wasn't fond of the idea (of these pieces always being under stress). To make matters worse, I had followed Sam James' (normally) good advice to leave a 1/4 inch spinner gap only to find that I had missed Jan Eggenfellner's good advice to leave a 1/2 inch spinner gap to improve PSRU cooling. Well, to make a long story short, I'm solving both problems with more fiberglass work. I've marked up the cowling to show the new point that will be the 1/2 inch gap location. In order to make the marks, I had to fashion a tool to mark the circumference (plane) of the new front edge. That was kinda fun ;-)
Tool shown marking the inside flange trim location. To mark the outer ring, pen attached to outer arm
A look at where the new line is (and how mis-aligned the current line is!!! Not my best work.)