Originally Posted by tjradj

I agree that I get better results without a gadget. I don't know the math formula, but if you're using folded binding, the amount of overlap that you need to make a mitered joint is exactly the full with of the binding.
For example, if you're using 2 1/2" strips for binding - folded in half and sewn on. You'll over lap the ending "tail" over the beginning "tail" by 2 1/2" Then unfold the end tail and place it right side up. Open up the end tail and place it right side down on top of the end tail so that the ends make a right angle. Pin in place. Sew a 45 degree angle across the point. Check it that you have it the right way before cutting off the tips. Refold and sew it down. You're ready to flip it over and handstitch it down.

Originally Posted by spokanequilter

I have both the Fons and Porter tool and the one demonstrated by Missouri Quilt Co. and I have never had any luck using them. The instructions are confusing with both and it seems like the ends never fit perfectly. Then I saw a video on YouTube that made it so simple. So, forget the binding tools! All you need to do is overlap the ends of the binding by however wide your binding strips were cut - e.g. if you use two and a half inch strips for the binding, then you overlap the ends by two and a half inches. Trim. The join the ends with a diagonal seam, trim the seam and finger press it open, and then finish sewing the binding to the quilt. Easy schmeezy and you get a perfectly smooth binding.