What is a “Scant 1/4 inch” and why is it important in quilting? Piecing with a Scant 1/4″ seam allowance can make a huge difference in the accuracy and appearance of your finished quilt. Here’s what it is and why it matters. (This post has been updated in 2019)
As you know, a 1/4″ seam allowance is the gold-standard in quilting. Keeping your seam allowance consistent is an important key to good-looking quilts but using a scant 1/4″ seam is even better. Let me explain.
Typically lining up the edge of your fabric with the right side of your presser foot is a good guide for keeping your seam allowance consistent. You can buy a specific quilter’s foot with a 1/4″ seam allowance for your machine (newer machines may come with one) but if you’re like me, I didn’t want to spend the extra money and it seemed close enough.
Then I took a class from Leslie Ison where she explained how much more effective it is to use a scant 1/4″ when piecing – especially when you are piecing a more complex block.
Above is are two seams on either side of a drawn line. On the right I just used my regular presser foot with the needle centered. On the left I adjusted my needle one space to the right and still used my regular presser foot.
Here is the difference. On the right you can see that the seam allowance is actually slightly bigger than 1/4″ – it falls just outside the 1/4″ line on the ruler. On the left you can see that the seam lies just slightly inside the 1/4″ line. This, my friends, is a scant 1/4″.
The reason this makes a difference is that by the time you open up the pieces and fold one side over (when pressing seams to one side – which is what I recommend) you lose a little bit of fabric real estate, making the pieced blocks slightly smaller. Multiply that by numerous seams and a block can shrink as much as an 1/8 or 1/4 of an inch.
I frequently get emails where people are making one of my patterns and the block comes out too small. 99% of the time, their seam allowance is too wide.
So get out your ruler and measure your seam allowance. Making adjustments may be as simple as moving your needle one notch to the right. But this simple adjustment of sewing with a scant seam allowance will make a big difference in your piecing. Especially if you’re piecing smaller, detailed blocks.
Give it a whirl and let me know if it makes a difference for you.