I do straight across seams in borders. The only way I would do a diagonal seam would be if the design in the fabric was so obvious that I had to do a different seam to hide the joining. Most fabrics are printed fairly straight and matching is not that much of a problem or doesn't show up at all with a straight seam. You really lose a lot of fabric by making a diagonal in a wide border. But if that is how YOU want to do it, then go for it. Just because most of us don't doesn't make it right or wrong. Quilting is so much about personal choice.
I do try to keep the cut of the fabric for the border the same. Is I am cutting WOF, then all the border for that one fabric is cut WOF. If I am cutting with the grain, then the same applies. There is more stretch in WOF.
For bindings, I always sew it as a diagonal seam. It takes a lot of the bulk out of the joining when they end up offset with the diagonal seam. I also, iron my seams open in the binding. But not in the borders.
Last edited by Barb in Louisiana; 02-08-2015 at 04:14 PM.