I'm making a headboard for a bed with an arched upper rail and vertical slats (1-3/4 wide x 3/4" thick). The lower rail is straight. I was going to shoulder tenon the ends of the slats and I have a horizontal mortising machine to cut the mortises. But what is the best method to get the verticals straight into that curvature?
I'm open to other joinery methods to make this easier but durable. Thanks.