This is from some plans I found online - If you're a woodworker, these are pretty useful. I used a 24x48 sheet of .5 inch Birch plywood from lowes and a .125 double-edged straight slot milling bit. www.woodmagazine.com/woodworking-plans/clamping/right-angle-jig-gives-you-a-corner-on-clamping-tasks