I haven't tried a piano key border but what about measuring the sides of the quilt then make two border strips about an inch smaller than half the length of the side of the quilt. Then cut a square for the center of the border strip the right size so that when you sew the border strips to each side of the square it 's the exact right length. Don't know if I'm being clear. In other words sew an odd size piece in the center of each strip on all 4 sides to enable the strips to be the correct size!? Might even want to make the 4 odd size pieces the same color to serve as accents.
Last edited by janjanq; 10-31-2017 at 08:57 AM.