Since there will be 11 arches in the addition and it would be a real pain to have to install a lintel over every one of them, I will be making the arches load bearing. I've made a form for pouring the key for the arches (above) and it should work on all the arches.
I was lucky to find some real nice eucaliptos just down the street, the perfect wood for my arch jig. A few months ago I free-handed an arch while closing in a window, it was pretty much a disaster, that's why I am making a jig for the rest of the arches. The jig will be sized for the smallest arch, for the bigger arches I will just overlay the jig with the proper diameter lumber.Ofcourse I needed a few new tools for these little projects.
A new jigsaw and a Jack plane, both cost the same, about $23 a piece. You can get a much nicer hand plane in the U.S. than this Stanley for $23 but it has the depth and angle adjustments on the iron and you can adjust the chip breaker, that's all I need.