I was contemplating what kind of guide to put on the top bars I was making. I considered all the options - line of wax, string, etc. I thought of beveling the top bar, but that's what I was doing when I cut my finger off with the table saw, which slowed progress somewhat and dampened enthusiasm for that project. Then I saw a piece of narrow half round molding in the shop, turned it over, and, voila, a perfect wedge! It's no problem to glue and nail with small finishing nails, even though the rounded part is down. (Wish I'd thought of that when I still had 10 fingers.) I just thought I'd pass that along.