Thank you all for your posts, very helpful. My friend is a newbie to quilting so perhaps between the 'ironing' vs. 'pressing' and maybe her 1/4 " seams not so accurate the problem may have been created. I did tell her about sewing the strips from opposite directions too.

This board is so helpful - my first time to ask a question. I'll surely be back with more fun questions as I'm sort of new to this too.

I sew in batches of 2, then join those into batches of 4, etc. Aside from accuracy, I can chain piece in this way, so I only need one leader/ender. If the strips are really long, then I alternate the direction of the seams. I just made a stacked coins quilt with 9" strips and this worked really well, when I was trimming the edges after quilting, the top was square.

Pressing with the iron using up and down motion instead of ironing, which pulls and pushes the fabric out of shape, works to prevent distortion.

I gave up on my 1/4" patchwork foot and started marking the bed of my machine with tape. I read somewhere to use Scotch brand reusable mounting strips and a Dritz seam gauge to accurately position it at 1/4". Love them both.

I've found that it's not so much in the sewing of long strips as it is in the pressing. I now use a pressing stick to keep mine straight. I saw one in use at a quilt show. The lady had over 30 three quarters of an inch strips sewn together starting from the same end and it was as straight as could be because she pressed the seams on a pressing stick. It's basically a half round covered with a very thin layer of batting and a muslin cover. My long one disappeared when I moved but I still have the short one.

I usually cut my strips on the lengthwise grain, instead of the width of fabric.

There is usually less stretch in the lengthwise grain, so less chance of distortion while being sewn.

Simple tools and using them correctly makes all the difference. That's why designer clothing cost so much. It's all in the details. I have learned I have to give every seam, every cut, every press, the same attention and care as I do the finest of applique. I use a Tailor's press on all my seams. And I press on a Steady Betty. The Steady Betty makes a big difference. The fabric does not move at all when pressing. It can't distort unless you force it. The right tools make my work look so much better. It took a long time for me to understand how important the smallest details matter in quilting.

How about a simple pencil line in the middle....I made a string quilt for my son and the center of each square was a 2" black strip, finished gave me a great design. So I figured an inch on each side of the diagonal point, and drew a line, also a little spray starch helped.....but if you keep that first line straight then the whole thing is straight....a good ruler can be a quilters best friend....

How about start your pressing in the middle and then go to either end.

My first thought was to check her cutting. Sometimes if the fabric isn't folded on the grain right, the strip is wonky near the fold when it's cut. if you have two cut poorly, there can be a big problem near the fold line when you sew them together.

use your walking foot, only sure way to perfection on strips piecing.