First I found some left over metal angle and my framing square. Then I pinned the angle against the square with small nails into a scrap of particle board. I put a nail right at the apex of the square, and you'll see why in a minute.
Then I took a piece of coroplast, a protractor, and a knife, and made a 45 degree triangle. Larry Rensberger to the rescue! ...again.
Then I nestled the pizza pan against the angles.
Then I lined up my coroplast triangle against the metal angle on one side, with the 45 degree side pointing at the nail at the apex of the framing square. It would've been more conveinient if the metal angle was taller than pizza pan, but oh well.
This puts the 45 degree edge of the triangle right through the middle of the pan. I marked it with a fine point Sharpie.
Then I rotated the pan roughly 60 degrees and marked it again. Then I rotated it another 60ish degrees and marked it a third time. I was pleasantly surprised at how accurately the three lines crossed.
Now I have the exact center from which I can mark out the lug nut positions.
