This is my new favorite way to do machine quilt binding. It's easy, strong, and looks gorgeous!
Lay your binding on the TOP of the quilt and sew using a .25" seam allowance. Leave a tail about 6"-10" long. Set your stitch length to 3.5, this makes the binding go faster and it's easier to keep it straight. You can use a long stitch here without it weakening the binding since you will be sewing it down again.
Now, as you are sewing down the side of the quilt, stop a few inches from the corner with the needle in the down position.
Fold your binding straight up from the quilt, this would be pulling the binding to your right.
Fold the binding back down against the quilt.
You will have a little triangular fold of binding at the corner. Fold this triangle down towards you. Sew along the quilt, then stop with the needle down .25" away from the corner. Turn the quilt and sew off the edge at a 45 degree angle.
Fold the corner back down. Continue sewing down the quilt from the top of the corner.
Repeat this for all of the corners. To end the binding, leave a 10" opening and a 6"-10" tail on both ends.
Trim one of the tails to be about 2/3 the length of the opening.
Line up a ruler with the edge of this binding tail.
Lay the other binding strip down and trim it so that it overlaps the first one by a distance equal to your bindings' width. I cut my binding to 2" wide, so my strip should overlap by 2".
Iron open your binding ends.
This part can be confusing. Turn the strips so that they are right sides together and are perpendicular to each other. This is easier if you fold the quilt in half.
Using the picture above as a guide, sew from the top left corner to the bottom left corner. Set your stitch length back to your machines default straight stitch length for this.
Trim the corner, then press the binding to the quilt. It should lay perfectly flat against the quilt. Sew the final section of binding down to the quilt.
Press out your binding from the quilt top.
Fold it over to the back just past your seam. Press well.
Pin from the top, going through the gap between the quilt and binding and catching the binding on the back. Place a pin every 6"-8" depending on how confident you feel in keeping the binding straight.
Sew down the quilt. Make sure you pressed all the corners well. If needed, sew one side at a time so that you can press the next corner between seams. I always do this because I think it really helps the corners be straighter. In the picture below, this stitch just does catch the binding on the back. When I press my binding, the back tends to end up wider than the front. This is fine as long as it catches everywhere. It also helps the corners line up better for a cleaner look.
Wait for the sun to shine through the windows and have a quilt photo shoot!