If you're stretching the binding a bit while you stitch it on, your quilt edge will be a bit wavy. The same will be true if you stretch your quilt top as you sew. Either if these things can happen, even with a walking foot, since a WF will only keep the fabric layers even as they are stitched not before the fabrics get to the foot.

Pinning close may be the answer but I wouldn't want to have a quilt full of straight pins flipping around on my lap!!

Sharon Schamber uses Elmer's glue to "pin on" the bindings. Using a fine tip (purchase at Purple Daisy's) on your glue bottle or the purple Elmer's glue stick,apply it to the edge of the quilt , lay down the binding and lightly press with an iron to dry the glue.
This method does''t take much more time than pinning, nothing slips and you won't get stuck and bleed on your quilt! It washes out easily and will not harm your fabric since the school glue is water and starch. Child safe, you know! She does this on show quilts so you know it's good.

I don't do this for every quilt only the "important "ones. A little ripple in a baby, child's or charity quilt is OK with me.

Yep ! Starch is good !! I use lots !!!

Cathy,
Your son's quilt sounds like a well-loved quilt.

I am surprised how attached guys get to the quilts we make for them. I made a quilt for one of my sons years ago. He has lived all over the United States. Sometimes he would load everything he could fit into his car and move, and leave the rest. When he moved back home years later, I was surprised that he still had the quilt I made for him. He said, "Mom, if I can only take one thing with me when I move, it is going to be the quilt my mother made for me."

Marilyn,
Good tip about cutting the binding slightly off-grain. I have done that a few times when I was short on fabric, but felt like I was cheating! I will quit feeling that way! That would distribute the wear and tear on several threads instead of just one end thread.

I prefer bias binding if I have enough fabric. Yes, it can get wonky. However, with some experimenting, I found that if I starch the binding fabric very heavily first, and am careful handling it, I don't have a problem with the bias stretching. I buy the big bottles of Sta-Flo liquid concentrated starch and use a 50/50 ratio (50% starch concentrate and 50% water). I starch it until it is stiff as crisp heavy paper. It takes more prep time, but it makes sewing on the binding a lot easier for me.

Judith

Very clever, Marilyn. Thanks

I don't remember whose tip this was, but long ago I learned to cut my straight grain binding
strips just a bit off grain...so as to reduce that wear problem . I have done that a long time and
not had one split on the edge yet !! Bias used on a straight edge can present it's own problems
of stretching and rippling. IMHO

Thanks for the tip Judith! My son brought me back a quilt I had made for him years ago so I could replace the binding. I replaced the binding, but used straight grain fabric. I did use the folded method. I guess by the time it is ruined, the rest of the quilt will by too.

I hadn't thought about the bias edge being able to withstand more wear and tear, but I bet you are right.

Sounds like the edge is being stretched in the binding process.
After squaring up the quilt sandwich, you might try stay-stitching the edge, just inside the seam allowance that would be covered up with the binding. I learned this in garment sewing.
I like to stay-stitch with a walking foot, and sew the binding on with the walking foot.
I had one quilt that wanted to go wavy on the edge even after I stay-stitched it. I basted the edge by hand with a strong thread to ease it into shape. That worked.
I use both glue and Wonder Clips to hold binding in place to sew.

If you starch your binding fabric first, and cut it lengthwise on the grain, that ought to help. I use straight-of-grain binding on quilts that won't get much wear - like wall quilts. However, the first quilt I bound with straight-of-grain binding wore out on the outer edge, where the one or two threads running up and down on the very edge of the binding got all the wear and tear. The binding literally wore out in two strips, one strip on each side of the quilt hanging onto the seam. So I use bias binding on utility quilts that will get a lot of use.
Judith

With all the extra layers added when doing binding and even more if you do double french fold like I do. I end up with layers like this:

binding
binding
quilt top (maybe even this is doubled where a block seam exists on the edge where I"m binding)
batting
quilt bottom
binding
binding

that is thick! So on my older machine, I end up having to change the pressure of my presser foot (and with my walking foot too) in order to have it not stretch my binding as I sew it.

You might try lowing the presser foot pressure .. maybe it would help . Remember to put it back for regular sewing.

Are you using a bias binding? You only need to do that for quilts with shaped edges and the straight of the grain is much less stretchy. Also, you could try starching the binding pretty heavily, glue basting it on the first side you stitch it on, and measuring it (though I never measure mine anymore, I did at first). Hope you solve this problem. It's just the kind of frustrating thing that can drive a quilter crazy.

These are all great suggestions. In my summer projects, I will try to adjust all of these variables - measure the binding, pin or glue it in place before stitching, and check out the impact of the decorative stitching. I am confident you all have contributed to the solution!!!!! Thanks for the kind words on my profile picture. It is a block from my very first full sized quilt. My husband is of Dutch descent, and he was so kind to buy my machine, that I felt it needed to be tulip fabric with tulip blocks. I even did free motion tulips in the plain blocks. We are still sleeping under it and dreaming of getting to Holland someday!

Another idea. I agree the ideas already mentioned. In addition, is it possible that the decorative stitching may pull the inside of the binding together causing the outside edge to wave?

I am wondering if it is possible that you are slightly pulling the binding as you sew it on with your walking foot? The other thing you could do is use little dots of glue to hold the binding in place before you sew and that way it shouldn't shift. I like your profile quilt photo too.

Love your quilty profile picture