Help is keep back and front straight
 

I have a horrible time when i add my back. I pin it and it looks like it is all straight and then when I go to add the binding, one side is wider than the other or it is turned. I don't know what I do wrong. I belong to a church group who make quilts to give away and somehow I always end up with a crooked edge. Is there an easy way to make sure your quilt turns out straight.

is the problem while quilting? do you pin every 4" in a grid? then quilt it- to the extent determined by the batting? (some batts say you have to quilt every 2"-4" some allow up to 10" between quilting lines)
then when the quilting is finished do you square it up? then add the binding? it is normal for (some) distortion after quilting- it is like doing embroidery or applique- as it is quilted the fabrics are drawn up to some extent- so a little bit is normal- that's why the quilt needs to be squared up after quilting/ before the binding.

I have started putting safety pins down the center of my backing, on the right side, stretch out on the dining table put center of batting along the pins, pin down the center of quilt top. I then smooth out to the sides, clamp them to the table. I feel for the pins on the down side of the backing and pin down the center. After I have it all pinned together, I flip it over and take the pins out of the back. A little more time spent but, It makes it easier to pin and makes the backing fit better.

I use Sharon Schamber's method to baste and never have that problem. You can find videos showing her method on youtube.

You might want to try spray basting. I find that things don't distort or shift when I use this method and there is no pinning necessary.

I found spray basting and it such a dream to quilt, no ripples no extra yardage.

One of the suggestions is to have the backing fabric at least 4 inches bigger on all sides. For some reason the backing fabric seems to draw up when it is quilted. If it is bigger to start, then you can trim to size before you put on the binding.