A Lesson on Seam Allowance

Yay! The 12 baby quilt blocks are assembled!! Whew, that was a lot of work. These pieces range in size from 1” to 7” and that requires a lot of sewing. Thank goodness for audio books, they really help to break up the monotony of running 192 – 1 1/2” squares through the sewing machine.

Dutch Windmill Blocks 2

While assembling some of the smaller sections, I was paying special attention to keeping my seam allowances straight. Several times my mind wandered to a particular group quilt class that I took a few years back, and the large number of participants that made careless crooked seams and/or seams that were improperly measured. That might work for quilts that have larger pieces, but when working with very small pieces of fabric it is imperative that your seam allowance be perfect, or as close to it as you can manage.

For a quilt block like the one I am working on, a quilter really needs to striving for perfection right from the get go, especially when the smaller pieced sections butt up against larger un-pieced, pieces of fabric. Here is what I mean:

Measuring Distance

If this is the first time you have done this, I recommend that you take the time to measure the distance between your needle and your guide. For me, my guide is the edge of my pressure foot. If you notice, I have a 1/4″ mark on the bobbin cover which is convenient, but in my case, it is not 1/4″ away from anything. It is an inaccurate mark, so I never go by it. Instead, I move my needle to 1/4″ away from the right edge of my pressure foot.

Measuring Seam Allowance1

Once you have the needle in the position you think it should be in, run a test piece and measure the distance between the edge of the fabric and the actual seam. In this case, I had moved my needle to exactly 1/4″ away from the edge of the pressure foot, but when I sewed the two pieces of fabric together is clear to see that I do not have a 1/4″ seam.


Measuring Seam Allowance 2

On this test piece I moved the needle over about 1/16″ and I made a near perfect 1/4″ seam allowance.



Once both pieces were sewn and pressed it is really easy to see the size difference.


Seam Allowance Mishap

When matched up to the solid piece that it is to be sewn to, The first section that I sewed does not line up, even if extra tension is applied to the pieced section. (Which by the way is a huge no-no.)


Proper Seam Allowance

This one is a near perfect match and my final quilt section will be an accurate size.


Being off this little doesn’t seem like it would matter a whole lot, but it really does. I always check my seam allowance before starting a new project because different fabrics press differently and that gives you different readings and I have come across sewing needles that do not always have the thread hole exactly centered. Also, if I change my pressure foot, I recheck my measurements. It is better to spend 5 minutes checking for seam allowance accuracy than to have the whole project come out askew.


Happy Sewing!



5 thoughts on “A Lesson on Seam Allowance

  1. Thanks for this very clear illustration of the importance of stitching an accurate seam. I taught a class last Saturday and was amazed at how many participants hadn’t measured an accurate 1/4 inch on their machines and then were surprised their blocks, comprised of 12 separate units, were not fitting together perfectly! Lesson learned – always start a class with a 1/4 inch seam test!

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  2. You are right on the money. And each machine is different. Another thing to take in account is the thread one uses. I use Aurifil 50wt in my Husqvarna because it does not throw off my 1/4″ or scant and the machine likes it. My long arm loves Robinson Anton thread. Interesting how thread makes a difference to each machine. Most patterns state 1/4″ but that might equate to a scant depending on the machine. Good advice to all. Thank you.


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