If the cause is what I think it is, your binding fabric is stretching as you apply it. What helps me is (1) heavily starching the binding fabric before cutting it into strips, (2) not pressing a fold into it before applying, (3) sewing with a regular sewing foot instead of a walking foot, (4) sewing with the binding on top, and (5) sewing on a cutting line I have marked on the quilt with permanent marker and trimming the quilt **after** sewing the binding on.

I know it seems counter-intuitive to not press the binding strip in half before applying, but this actually helps the binding lay smoother. This is because when you go to turn the binding, the outside layer of binding requires a little more fabric and the inside layer of binding requires a little less fabric. This adjustment happens automatically if you have not first pressed your binding strip in half. You just need to be careful at the beginning of sewing to make sure that your binding edges match; just takes a few seconds to hand fold a length to make sure you are starting off right.

Starch stiffens the binding so that the binding fabric is much less likely to stretch as you sew.

Marking the cutting edge (I use a permanent Sharpie) and using the mark as a "virtual" edge helps me a **lot**. I don't have loose backing to get folded under as I sew. Just be very careful not to cut the binding at the corners when you do finally trim the quilt. I decided to trim the corner seams once and ended up with holes in my binding! If I want to trim a corner now, I do that after trimming the entire quilt and then trim away only the quilt sandwich at the corner, not the binding.

I measure my quilt - top, centre & bottom, take the average then I subtract 1/2". I never have wavy binding. Works for me.

I agree with Prism - you might have been pulling the binding too taught as you were sewing it on (been there, done that, got the t-shirt), and don't press your binding in half before sewing on.

I think the people who said to measure and take an average are referring to borders, not binding. You can't really cut your binding to size before attaching it (at least I don't think you can) because you need some overlap when you join it. You can get a perimeter size and add about 10 inches to figure out how much binding to cut.

I always baste about 1/8" in from the edge of the quilt before applying the binding. It keeps the quilt edge from stretching out as I put the binding on. That may help with the waviness.

Leslie

Folks here are saying measure in centre etc is for borders. I wonder if your border is too long and when the binding is attached it results in a wavy edge. I would look at the border first..

Thank you Dunster! I was wondering what I was missing! I don't normally have wavy bindings.

Interesting - how we have different ways of trying to arrive at the same place.

I trim the sandwich before applying the binding. I also "stay-stitch" the three layers together before starting to apply the binding.

I cut bias strips about 2-7/8 inches wide and my finished binding is about 7/16 inches wide. I like a wider binding and that's the width that "works" best with the leftest needle setting on my machine.

I do not starch the strips - I do "loosely fold" the binding and machine baste the raw edges together. I also DO NOT press a crease into it for the reason Prism99 stated.

With the quilt edges sewn together and the binding edges sewn together, I only need to fret about lining up two sets of edges.

The extra sewing does take a bit longer - but it took me longer to undo and resew a layer that had bunched up when I did not do the extra sewing.

I find that the bias binding does "stretch" a bit while applying it - which results in a binding that "hugs" the edge and lays beautifully. (If the binding was cut at 100 inches, for example, I would have used 99 inches of it)

P.S. I always do a bit of a "practice/test run" for how wide to cut the binding and/or which needle position setting to use before cutting out all the binding and/or sewing the binding all the way around.

If I am going to hand stitch the binding to the back - then I want the binding to barely cover the machine stitching.

If I am going to wrap the binding to the front and then machine stitch it down, then I want the binding to overlap the first stitching by about 1/8 inch.

WOW, that is very wide binding. If you are working with bias binding, I usually starch the heck out of before I cut. If you baste your quilt prior to binding, that is when I would check the diagonal measurement of your quilt. Yes, we have many different ways to get a single thing done and it is important that each one of us find the best and easiest way to complete our quilts.

Wide binding - I like the look - but that may be just because I am used to it -