Are you saying that the border is wavy as well, or is it just the binding?

The best way to measure the border is measure the center across the MIDDLE. Cut the border to that dimension and attach it to the center (each side). Ease in any imperfection by distributing the difference along the entire border. Then remeasure and repeat for the other two borders. (unless you are mitering your corners, then the instructions are a little more involved.)

I do continuous binding and never measure that part and I have never had a wavy border. Good luck - "unsewing" is never fun.

I am rechecking the wall hanging, yes the outer edge of the border is larger than the center by about an 1" OMG!!!!!!!! Guess I will have to nip and tuck this piece after I have removed the binding. Try, try again. Will let you know what happens, thanks for all the advice, I looked at the YOUTUBE and that's a great place to keep on a bookmark. Bea

A tip for next time, sew the border on with the border strip on top of the quilt top. The feed dogs will slightly ease in whatever is on the bottom. If you sew with the quilt on the bottom it will slightly ease it into the borders. You definitely don't want the borders eased into the quilt!

I had one come up wavy once. I was in a rush and did not pin it before sewing it down.