Bigger is Better - Backing that is.
Every once in awhile someone will send me a quilt to work on that also sends backing and batting that are the same size as the quilt top.
No no no no - please don't do this - I need the extra on the ends to attach to the canvas leaders on the machine and to give room for the quilting machine to maneuver and I need the extra on the sides to attach clamps to the backing to keep good tension to prevent pleats being sewn into it, and also so the machine can maneuver around.
Here is a photo tutorial of why it is so important.
This is how the quilting machine is set up.
Backing loaded on the quillting machine.
This allows the machine to get right to the edge of the quilt top.
This is backing the same size at quilt top. Machine cant quit up to the edge of the quilt top.
Bad - not enough and will have to work on it.
With the backing bigger than the top I can get right up to the edge of the quilt top when quilting.
This is the quilt backing too short.
No way to quilt to the bottom edge of the quilt. I will have to take it off and add backing fabric, if I don't have matching fabric then it will show.
I hope this helps you understand the importance of making sure the backing and batting are at least 3 or 4 inches bigger on ALL sides of the quilt top.